Pregnancy, Childbirth, and the Newborn: The Complete Guide, 4th Ed.

CHAPTER 7 When Pregnancy Becomes Complicated

Most women have normal and healthy pregnancies. But for some women, a chronic (preexisting) health problem or one that develops during pregnancy can cause complications and make pregnancy challenging, alarming, or stressful. If complications occur in your pregnancy, knowing the warning signs on page 70 will help you detect and report a problem early on. Having good prenatal care and prompt treatment may minimize complications and maximize your chances of having a healthy baby. In this chapter, you’ll learn about complications in the order in which they may appear in pregnancy, beginning with conditions that may affect your pregnancy from conception and ending with complications that can arise in the days before the birth.


In this chapter, you’ll learn about:

• Medical problems that sometimes occur for mothers or babies during pregnancy

• Diagnostic tests used to detect specific pregnancy problems

• Treatment options for pregnancy complications

• Ways to reduce your risk of developing serious problems from complications such as preterm labor and preeclampsia

Chronic Conditions That May Affect Your Pregnancy

If a woman has a chronic condition or illness before becoming pregnant, it might or might not cause problems in pregnancy. With good prenatal care, most women with chronic health problems have healthy babies.

The following is a list of conditions and illnesses that may affect prenatal care:

• Cardiovascular disease (high blood pressure, heart disease, or sickle cell anemia)

• Gastrointestinal illness or nutrition problems (inflammatory bowel disease, phenylketonuria or PKU, Crohn’s disease, eating disorders, or gastric bypass surgery)

• Respiratory or lung disease (asthma)

• Hormonal imbalance or disease (diabetes, thyroid disease, polycystic ovarian syndrome or PCOS, or pituitary disorder)

• Autoimmune disorder, in which the immune system harms instead of protects the body (rheumatoid arthritis, lupus erythematosus, and antiphospholipid antibody syndrome or APS)

• Other condition or illness (kidney disease, epilepsy, or physical disability)

If you have one or more of these conditions or illnesses, you improve your chances of having a healthy baby by controlling the symptoms before becoming pregnant. Once you’re pregnant, talk with both your regular physician or specialist and your maternity caregiver to create a plan for maintaining your health and to learn what you can expect during pregnancy, labor, and the months after the birth.

Complications That Arise in Pregnancy

Some complications that arise in pregnancy are more serious than others and require medical treatment. Other complications resolve with little or no treatment. The following sections discuss the most common complications.


Spotting or light vaginal bleeding in the first trimester occurs in about 20 percent of all pregnancies. In many cases, the bleeding doesn’t harm the mother or baby.

What causes bleeding in early pregnancy? Sometimes, the implantation of the fertilized egg into the uterine wall causes slight vaginal bleeding, usually shortly before the time a woman expects a menstrual period. Other times, cervical tenderness and an increased blood supply to the pelvis can cause spotting after a woman has intercourse. Often, frequent strenuous exercise or a cervical infection causes vaginal bleeding. In rare cases, a condition called molar pregnancy causes brownish vaginal discharge in early pregnancy. In a molar pregnancy, abnormal placental tissue grows into a grape-like cluster; there isn’t a baby, even though a pregnancy test is positive.

For about half the women who experience bleeding in early pregnancy, the bleeding stops on its own and many women have no further complications. In other cases, the bleeding is serious and sometimes indicates an ectopic pregnancy or possible miscarriage. (See below.) Women who have continuous moderate or heavy bleeding are more likely to miscarry than those who experience light bleeding only once.

If you experience any vaginal bleeding during early pregnancy, call your caregiver. If you have spotting or light bleeding for only one day, your caregiver may suggest that you rest and avoid strenuous exercise and sexual intercourse. If you experience heavy bleeding along with cramps or abdominal pain, your caregiver may order an ultrasound scan or blood tests to assess your pregnancy.


About 1 to 2 percent of pregnancies are ectopic. An ectopic pregnancy occurs when the fertilized egg implants itself someplace outside the uterus, usually in the wall of a fallopian tube (called a “tubal pregnancy”) but sometimes in the cervix, ovary, or abdomen. This type of pregnancy won’t result in a live birth, thus parents feel a similar sense of loss and grief that a miscarriage evokes (see below).


Symptoms of an ectopic pregnancy usually appear in the first six to eight weeks of pregnancy and may include lower abdominal pain or tenderness (or one-sided pelvic pain) and vaginal bleeding. Additional symptoms include nausea, vomiting, dizziness, or a sharp shoulder pain. An untreated tubal pregnancy causes severe abdominal pain and vaginal bleeding that indicates internal bleeding.

Early diagnosis of the problem and rapid treatment help preserve a woman’s future fertility and greatly reduce the risk of death from severe blood loss after a tube ruptures. To diagnose the problem, a caregiver assesses the woman’s hormone levels to evaluate the viability of the pregnancy and examines a high-resolution ultrasound scan to discover the implantation site. Surgery may be needed to confirm the diagnosis or to remove the embryo. An intravenous (IV) infusion of a medication called methotrexate may be used to abort the pregnancy or may be combined with surgery to ensure the full removal of pregnancy tissues.

The likelihood of ectopic pregnancy rises for women whose fallopian tubes are damaged by pelvic infection, disease, or surgery. The majority of women who have an ectopic pregnancy can expect to get pregnant again and carry a healthy baby to term.


miscarriage (or spontaneous abortion) is the unexpected death and delivery of a baby before the twentieth week of pregnancy. About 10 to 15 percent of known pregnancies end in miscarriage; however, the percentage of early miscarriage (occurring between the first and thirteenth weeks of pregnancy) is probably higher because many women might not have realized they were pregnant before the loss occurred.

Although no one knows the specific cause of most miscarriages, the most commonly suspected reason is random chromosomal abnormalities that interfere with the baby’s normal development. Other factors that increase the risk of early miscarriage include a history of infertility and assisted conception, advanced age of the woman (or man), high body temperature, infection, hormonal imbalance, high intake of alcohol or caffeine, smoking, low body weight along with poor diet, frequent high-impact or strenuous exercise, and extreme emotional stress or physical injury.

Common Q & A

Q: My last pregnancy ended in a miscarriage. What can I do to increase my chances of carrying my next baby to term?

A: To improve your chances of a healthy pregnancy after a previous miscarriage, try to do the following:

• Have a well-balanced diet.

• Take prenatal vitamins.

• Avoid environmental toxins and infections.

• Don’t smoke or use recreational drugs.

• Avoid extremely stressful relationships as much as possible before and during pregnancy.

• Make arrangements for emotional support and medical monitoring, starting early in pregnancy.

Factors that increase the risk of late miscarriages (occurring between the fourteenth and twentieth weeks of pregnancy) include uterine abnormalities such as an incompetent cervix (see page 138), acute infection (see page 132), placental circulation problems (see page 139), uterine fibroids (see page 129), and certain chronic illnesses (such as autoimmune disorders; uncontrolled diabetes; thyroid conditions; and heart, liver, or kidney disease). Treatment of these possible causes can help prevent a miscarriage.

Once a miscarriage starts, it can’t be stopped. Signs of a miscarriage include vaginal bleeding and intermittent abdominal pain that often begins in the lower back and develops into abdominal cramping. If you suspect you’re having a miscarriage, call your caregiver. He or she may advise you to rest and wait to see if the bleeding stops or may order an ultrasound scan and a blood test to confirm whether you’re still pregnant. If you’ve had a miscarriage and you’re Rh negative, you may receive a shot of RhoGAM. (See page 135.)

Sometimes a caregiver discovers that a baby has died before a miscarriage begins. The shock that such a discovery gives expectant parents, combined with waiting for the miscarriage to begin on its own, can be extremely stressful. Some women want an immediate end to the pregnancy by receiving medications to expel the baby or by having surgery to clean out the uterus (dilation and curettage, or D&C). If you’re in this situation, discuss the potential risks of these medical procedures with your caregiver. If you decide against them, stay within a thirty-minute drive to the hospital in case you experience heavy bleeding, fever, or strong abdominal pains while awaiting the miscarriage. Be sure to surround yourself with people who can support and nurture you during this difficult time.

It’s normal for a woman to feel shock, grief, and sadness after a miscarriage—especially when the pregnancy was wanted, had been achieved by medical or surgical help, or followed a previous miscarriage.

If you experience a miscarriage, you and your partner may need extra rest and support. Even if you hadn’t announced your pregnancy to others, seek comfort and help from family and friends as well as from books and support groups on pregnancy loss. Talking about your loss with people who have experienced a miscarriage may be a particularly helpful way to ease your pain. (See also page 303 for useful information.)

Most women who have one or more miscarriages eventually give birth to healthy babies. As you begin planning your next pregnancy after a miscarriage, consider asking your caregiver about medical tests or genetic counseling to determine a possible cause of the miscarriage, to screen for genetic disorders, and to treat a harmful infection or chronic condition. You also may want to seek emotional support to help you manage your fears of another miscarriage, at least until your next pregnancy passes the point at which the miscarriage occurred.


Having a high body temperature (an oral temperature over 100.4°F or 38°C) for three to four days may harm your baby, especially in early pregnancy. If you have a prolonged fever, ask your caregiver for advice. Don’t take any fever-reducing medication unless your caregiver instructs you to do so. To lower your temperature, drink plenty of liquids and take a lukewarm bath or shower. If your temperature is higher than 102°F (38.9°C), call your caregiver immediately.

Be aware that soaking in hot tubs or taking saunas may raise your body temperature to a level that can be dangerous to your baby. (See page 83.)


Hyperemesis gravidarum is persistent, severe nausea and vomiting. While nausea and vomiting is the most common complaint of early pregnancy, the intensity of hyperemesis gravidarum far exceeds that of “morning sickness” (see page 40). This serious condition, which affects less than 1 percent of pregnancies, can result in weight loss, dehydration, and changes in blood chemistry.

If you’re extremely nauseated and continue to vomit food and fluids for a day or longer, call your caregiver to determine whether the cause is illness or food poisoning. Early management of severe nausea and vomiting may help prevent its progression to hyperemesis gravidarum.

Treatment begins with the same dietary and lifestyle changes recommended for managing morning sickness (see page 119), along with suggestions for helping you keep down foods and fluids. If this treatment isn’t effective, your caregiver may prescribe medications to relieve vomiting (antiemetics) and, if necessary, to treat infection. If your vomiting can’t be controlled, you may need hospitalization to receive IV fluids. Some women feel nauseated throughout pregnancy and continue to take medications at home.

Sometimes, psychological problems can worsen hyperemesis gravidarum (they may even cause the condition); talking with a trained counselor may help resolve the problems and lessen the nausea and vomiting.

Hyperemesis gravidarum can be debilitating, but it’s manageable with treatment and only rarely causes lasting effects on you or your pregnancy. By treating the condition, you’ll help prevent dehydration and improve your quality of life.


Uterine fibroids are benign (non-cancerous) tumors of the uterine muscle. Up to 75 percent of women develop fibroids (also called “leiomyomas” or “myomas”) at some time during their lives, but the fibroids typically don’t cause problems. During their childbearing years, less than 25 percent of women with fibroids experience symptoms such as excessive menstrual bleeding, pelvic pain, or infertility; only some have surgery to shrink or remove them.1

Although fibroids typically don’t cause problems in pregnancy, possible complications include a slight increased risk of miscarriage, preterm labor, or postpartum hemorrhage. Depending on the number, size, and location, fibroids can sometimes complicate birth. Their presence may slow labor progress or interfere with the baby’s movement into a head-down position for birth.

If you’ve been diagnosed with fibroids, your caregiver will likely watch your pregnancy closely and use ultrasound scans to detect changes in the fibroids’ size or number and to determine whether they’re affecting your baby’s growth. If the fibroids are causing abdominal pain or increased pressure, treatment may include bed rest, applying cold or hot packs, and taking pain medications.


Venous thrombosis is a blood clot that typically occurs in a vein in the leg or pelvis. During pregnancy, pressure from your enlarged uterus slows the flow of blood returning from your legs and your blood changes how it clots to help reduce postpartum bleeding. Because of these changes, you have a slightly increased risk of developing blood clots in your legs during pregnancy or soon after the birth.

A clot that develops in a vein close to the skin is called thrombophlebitis, and it causes swelling, tenderness, and redness. Treating thrombophlebitis includes bed rest with the leg elevated, hot packs to the affected area, special support stockings, and a mild pain reliever if needed.

Deep vein thrombosis (DVT) develops in a big vein that’s deeper in your body and is much more serious than thrombophlebitis. DVT causes leg or pelvic pain and redness, warmth, or swelling near the affected area. If you have DVT in your calf, you may have increased calf pain when you flex your toes toward your knee.

If you notice symptoms of DVT during pregnancy or after the birth, notify your caregiver immediately. You may be at risk of developing venous thromboembolism (VTE) and possibly a pulmonary embolism, a potentially fatal condition in which a portion of the blood clot breaks loose and travels to a lung. Symptoms of pulmonary embolism include sudden shortness of breath, chest pain, and rapid heart rate. Your chances of developing VTE increase if you’re older than thirty, you or your family has a history of blood clots, or you’ve recently been on bed rest or been sitting for a very long time.

Treating DVT may require pain medication (if leg pain is severe) as well as hospitalization and IV doses of the anticoagulant (blood thinner) Heparin to prevent further clot formation. Heparin doses continue at home until the birth and are administered by self-injection, pump, or IV; then another anticoagulant, Coumadin, is taken orally for six weeks.


Although the risk of acquiring a serious infection during pregnancy is low, some infectious diseases can affect your pregnancy or harm your baby. The potential risks depend on the following:

• What organism (virus, bacterium, or spore) is causing the infection

• Whether you have antibodies to the organism from a prior exposure

• Whether the disease is treatable

• When during pregnancy you acquired the infection

Even if you get an infection during pregnancy, your baby might not become infected—and even if your baby gets infected, he might not be harmed.

The chart on pages 132–133 identifies infections that are harmful during pregnancy, and the following sections provide information on the most serious of them.

Ways to Avoid Getting Sick

The best way to prevent complications from an infection is to avoid getting sick. Here are a few guidelines to follow:

1. Wash your hands several times each day, especially before eating and after using the toilet. Germs live on doorknobs, handrails, phones, hands, and other surfaces. After touching a germ-covered surface with your hands, you transmit the germs to your food, mouth, nose, and anything else you touch.

2. Stay away from sick people as much as possible, especially if your vaccinations aren’t up to date.

3. Update your vaccinations or have your immune status checked before pregnancy, if possible. Health care professionals recommend that women avoid certain vaccines—such as chicken pox (varicella zoster) and measles, mumps, and rubella or German measles (MMR)—in pregnancy or in the month before conception. If you received MMR vaccines as a child, you may be immune to these infections. However, the effectiveness of some vaccines, such as the one for rubella, may diminish over time.

4. Eat safe foods. To avoid food-borne diseases, don’t eat certain foods during pregnancy. (See page 121.) Also, wash fruits and vegetables before eating them, adequately cook meats and other foods, and thoroughly clean your food preparation surfaces.

Sexually Transmitted Infections (STI)

Some STIs (previously called “sexually transmitted diseases” or “STDs”) can cause problems during pregnancy, but if treated early, the risks to the baby are minimal. If you’ve had multiple sexual partners, you’re at greater risk for an STI such as chlamydia, gonorrhea, genital herpes, hepatitis B, human immunodeficiency virus (HIV), human papillomavirus (HPV), syphilis, and trichomoniasis. If you have or had symptoms of an STI—such as genital sores, abnormal vaginal discharge, or discomfort or difficulty with urination—see your caregiver to find out if testing and treatment are necessary. Throughout pregnancy, make sure you and your partner practice safe sex to protect against exposure to STIs.

Group B Streptococcus (GBS)

About 10 to 30 percent of pregnant women are carriers of Group B streptococcus (or are “colonized” with GBS), which means GBS bacteria are present in their bodies but they don’t have signs of infection. Without treatment, about 1 in 200 newborns whose mothers are GBS carriers will develop a GBS infection, which can be life threatening. If these mothers receive antibiotic treatment during labor, their babies’ risk of infection drops to 1 in 4,000.

Most caregivers follow the GBS detection and treatment guidelines developed by the U.S. Centers for Disease Control (CDC) in 2008,2 which recommends screening a pregnant woman between the thirty-fifth and thirty-seventh weeks by swabbing her vagina and anus and having the secretions cultured in a laboratory. If a woman is a GBS carrier, her caregiver treats her with antibiotics during labor and watches her baby closely for signs of infection.

Women with the following circumstances may receive antibiotics during labor without prior screening:

• A urinary tract infection (UTI) caused by GBS during this pregnancy (even if she received antibiotics)

• A previous pregnancy with a baby who had severe GBS disease

If a woman hasn’t been tested or the results of the culture aren’t known when labor begins, she’ll receive antibiotics if she has any of the following risk factors:

• Preterm labor (labor that begins before the thirty-seventh week)

• Ruptured membranes for more than eighteen hours before labor begins

• Fever of 100.4°F (38°C) or higher

Antibiotic treatment of all pregnant GBS carriers is controversial. Although only a few babies of GBS carriers develop an infection, all these babies are exposed to possible side effects of antibiotics, such as allergic reaction, creation of drug-resistant bacteria, and yeast infections after birth. Despite the risk of these side effects, most GBS carriers choose antibiotic treatment during labor to reduce the risk of early-onset GBS infections in their babies.

Bladder and Vaginal Infections

Bladder or vaginal infections increase the risk of preterm labor. Symptoms of a bladder infection (also called “urinary tract infection” or “UTI”) include frequent urination, urgency to urinate, blood in the urine, and pain, especially at the end of urination. Symptoms of a vaginal infection include vaginal discomfort or itching and foul-smelling discharge. Note: It’s normal to have thin, mild-smelling, and whitish vaginal discharge during pregnancy.

If you think you have a bladder or vaginal infection, promptly call your caregiver for treatment.


Listeriosis is a form of food poisoning that can harm your baby. While rare, listeriosis affects pregnant women twenty times more often than it affects other healthy adults. The bacteria live in unpasteurized dairy products, raw or undercooked meats and fish, and in contaminated soil and water. Avoid eating unpasteurized milk and soft cheeses during pregnancy. Don’t eat meat, poultry, eggs, or seafood that isn’t cooked thoroughly. Wash produce before eating it and carefully clean all food preparation surfaces and utensils. (See also page 121.)

Infections during Pregnancy

The following chart describes how certain infections may harm your baby. Because the chart addresses serious potential complications, it may seem scary. But remember: If you get any of these infections, you can minimize the potential risks if your caregiver diagnoses the infection early and you and your baby receive prompt treatment.

If your baby is infected, the infection increases the risk of:


Birth Defects

Preterm Labor

Illness in Baby


Bacterial vaginosis (BV)




Problems result from prematurity.

Chicken pox (varicella zoster)




Slight risk of infection affecting one or all of baby’s organs.

Chlamydia trachomatis




Baby not affected before birth, but may have eye infection or pneumonia after birth.

Cytomegalovirus (CMV)




Risk of brain damage or hearing loss. About 10 percent of babies affected when mother is first infected in first trimester.

Fifth disease (parvovirus B19)



May cause severe anemia and related problems for baby.

Gonorrhea (Neisseria gonorrhea)



If baby is infected during birth, infection may cause severe eye infection that may cause blindness.


Birth Defects

Preterm Labor

Illness in Baby


Group B streptococcus (GBS)




If baby infected at birth, infection may cause severe disease or death.

Hepatitis B (HBV) or Hepatitis C (HCV)



If baby is infected at birth and untreated, she’s at high risk of becoming a HBV carrier, but at low risk of becoming a HCV carrier.

Herpes simplex virus (HSV)



Risk of infection is highest when mother has first outbreak of genital herpes in pregnancy. Any recurrent infection at birth may affect baby. Treatment of outbreaks reduces the chance of infection.

Human immunodeficiency virus (HIV)



Treatment of mother can greatly reduce the risk of baby’s acquiring HIV during pregnancy or at birth.

Human papillomavirus (HPV)



Low risk of baby’s acquiring HPV during pregnancy or at birth. May cause genital warts or cervical cancer later in child’s life.

Listeriosis (Listeria monocytogenes)




May cause miscarriage or infection in baby after birth.

Lyme disease




Bacteria from a tick bite can cross the placenta. Risks are unknown, but may cause miscarriage or stillbirth.


Birth Defects

Preterm Labor

Illness in Baby


Mumps (Paramyxovirus)



Although the connection is unconfirmed, infection may cause miscarriage. May cause infection in baby after birth.





May cause infection in baby after birth.

Periodontal disease (gum disease)




Severe gingivitis greatly increases risk of preterm birth.

Rubella (German measles)




When baby is infected in first half of pregnancy, infection increases risk of problems with hearing, vision, heart function, or brain development.

Syphilis (Treponema pallidum)




Possible problems with baby’s eyes, skin, heart, bones, and nervous system. May cause death.

Toxoplasmosis (Toxoplasma gondii)




Possible effects on all of baby’s organs; may cause death. Problems are more severe if mother is first infected in first half of pregnancy.

Trichomoniasis (Trichomonas vaginalis)




Problems result from prematurity. Infected mothers often have other infections.

Yeast (candidiasis)



Exposure may occur with vaginal birth, but infection is rare. Chances of infection on mother’s nipples or in baby’s mouth (thrush) increase if mother had antibiotics near time of birth. (See page 422.)

Key: X = Possible ? = Questionable


Cats are the most common carriers of the Toxoplasma gondii parasite, especially outdoor cats that eat rats, mice, and other raw meat. The parasite passes from a cat in its feces, and you can transmit it from your hands to your mouth if you don’t wash your hands after handling cats, emptying litter boxes, or working in soil that contains cat feces. You can also ingest the parasite by eating raw or undercooked meat or unwashed root vegetables.

If you’ve been around cats for many years, you may have become immune to toxoplasmosis, the infection caused by the parasite. However, tests for this immunity are unreliable and aren’t usually recommended.

If you get toxoplasmosis for the first time during the first trimester, the infection may cause congenital defects or miscarriage. If you’re infected during the third trimester, your baby may be born with the infection. Although you can treat toxoplasmosis with antibiotics, prevention is the best treatment. Wash your hands after touching a cat, have someone else clean the litter box, and wear gardening gloves. Also, cook your meat well and wash vegetables thoroughly.


Diabetes mellitus (also called “DM” or simply “diabetes”) occurs when someone has trouble making or using insulin, a hormone that helps glucose (sugar) pass into cells for the body to use as an energy source. There are two types of the disease. With type 1 DM, the body stops making insulin; with type 2 DM, the body uses insulin ineffectively. Without insulin, blood glucose levels rise dramatically and glucose passes into the urine. DM can cause serious problems in pregnancy if a woman doesn’t have proper medical care and nutrition.

When considering getting pregnant, a woman with DM needs to balance her medications with her activity level and diet. She may need to adjust her insulin dose or begin taking injections to control her blood glucose levels. She improves her chances of carrying a healthy baby to term if she controls her blood glucose levels before and during pregnancy.

Gestational diabetes mellitus (GDM), a form of DM that develops or is first recognized in pregnancy, affects about 3 to 5 percent of women. GDM is related to normal changes in glucose metabolism that promote the baby’s growth in the womb. Human placental lactogen (HPL) diminishes the effect of insulin and allows more glucose for the baby’s growth. In some women, their response to this pregnancy hormone is out of balance, leading to excessively high blood glucose levels.

Early detection and appropriate treatment of GDM can help prevent problems similar to those for a pregnant woman with DM who has high blood glucose levels, such as increased chances of a urinary tract infection (UTI), an overly large baby, preterm birth, stillbirth, and a newborn with hypoglycemia (low blood sugar), jaundice, or breathing difficulties.

Some caregivers use urine tests to screen for glucose in early pregnancy. Most caregivers use blood tests to screen for GDM between the twenty-fourth and twenty-eighth weeks of pregnancy. (See page 68.) If you’re at increased risk for GDM, your caregiver may suggest giving you the blood test earlier than the twenty-fourth week. Risk factors include women who have family members with DM, obese women, and those of Hispanic, African, or African American descent.

If your blood test is positive for high glucose levels, your caregiver will order a glucose tolerance test (GTT) to confirm the diagnosis, a process that requires blood tests every hour for three hours. (See page 145.)

If you have GDM, treatment includes a special diet, exercise, and (in some cases) oral medications or insulin injections. The clinic nurse will show you how to check your blood glucose levels. If your caregiver suspects that your baby is overly large or that your placental circulation is affected, he or she may induce your labor near term. After the birth, your blood glucose will probably return to normal levels; however, about half of the women with GDM develop type 2 DM later in life.


A characteristic of blood types is the presence or absence of an antigen called the “Rh” or “RhD factor.” If your blood type includes a plus sign (such as O+ or A+), the Rh factor is present. More than 85 percent of the population is Rh positive. If your blood type includes a minus sign (such as O- or A-), the Rh factor is absent. About 15 percent of Caucasians, 3 to 5 percent of people of African descent, and few people of Asian descent are Rh negative.

In early pregnancy, your blood is tested for the Rh factor. If your blood is Rh negative, then your baby’s father needs to have his blood tested as well. If you’re Rh positive and your baby’s father is Rh negative, or if both of you are Rh positive or Rh negative, all is well. However, if you’re Rh negative and your baby’s father is Rh positive, then your baby may be Rh positive—and if so, you and your baby are Rh incompatible.

Although you and your baby don’t share blood systems, if you and your baby are Rh incompatible, his blood may enter your bloodstream when you give birth or if you experience a miscarriage or have invasive tests such as amniocentesis or chorionic villus sampling (CVS). As a result, you may become Rh sensitized and start producing antibodies that may cause mild to severe anemia in your baby. Because your body produces antibodies slowly, the first Rh-incompatible pregnancy is usually unaffected. Without treatment, however, a problem can arise in a future pregnancy if that baby is also Rh positive.

Injecting an Rh-negative mother with Rh-immune globulin (RhoGAM) at the twenty-eighth week of pregnancy can prevent Rh sensitization. RhoGAM is also given after a miscarriage or abortion, with any invasive procedure, or if necessary after uterine bleeding or trauma. If a blood test finds that the baby is Rh positive, the mother receives another dose of RhoGAM within seventy-two hours of the birth.

Although RhoGAM has made Rh sensitization rare, if you’re Rh negative your caregiver will test your blood for antibodies throughout your pregnancy. If the level of antibodies increases, amniocentesis helps assess how seriously the antibodies have affected your baby. In severe cases of anemia in the baby, treatment may include early birth and a blood transfusion to replace blood cells. Only in extreme cases does a baby need a blood transfusion in the womb.


In late pregnancy, heavy vaginal bleeding may suggest problems with the placenta’s attachment to your uterus, such as placenta previa or placental abruption. (See pages 139–140.) Call your caregiver immediately if you experience fairly heavy bleeding. Slight spotting in late pregnancy may be a normal sign of labor; however, if your pregnancy is less than thirty-seven weeks, the spotting may indicate preterm labor.

Preterm Labor

preterm labor is one that begins before the thirty-seventh week of pregnancy, and births that result from preterm labor are called preterm births. About 10 to 13 percent of births are preterm, and their frequency has increased in the United States since the early 1990s. Although no one completely understands why the number of preterm births has risen, some experts speculate that several factors contribute to the cause, including the following: a greater number of women who are delaying pregnancy until their thirties or forties, increased use of reproductive technology that results in more pregnancies with multiples, and a greater number of elective inductions and planned cesareans with incorrect estimates of the baby’s gestational age.

Because preterm babies are immature and underdeveloped, they tend to have more health problems than full-term babies do. Very premature babies (born before the thirty-second week of pregnancy) have an even greater risk of life-threatening complications. (See page 392.) Good prenatal care strives to prevent preterm birth by identifying those women most likely to have preterm labor.


Several factors can increase the risk of preterm labor. Although many women with these risk factors deliver their babies early, many don’t. The factors simply mean the women are more likely to have preterm labor than others are—but even women without these risks may have preterm labor.

• Previous preterm labor or birth

• Pregnant with multiples

• Previous abortions

• Abnormally shaped uterus or previous uterine or cervical surgery

• Current infection of the vagina, amniotic membranes, bladder, or mouth and gums (See pages 132–133.)

• Bleeding during pregnancy

• Obese or extremely underweight before pregnancy

• Poor nutrition before or during pregnancy

• Older than thirty-five or younger than sixteen

• Use of reproductive technology to become pregnant

• Heavy smoking or drug abuse

• Disease in baby or birth defects

• Constant emotional stress (domestic violence, extreme poverty, workplace pressures, or other severe stresses)

• High degree of physical stress (heavy lifting, long periods of standing, or very strenuous exercise)

How to Check for Contractions

1. Empty your bladder and drink two tall glasses of water.

2. Recline with your feet up or lie on your side. Relax.

3. Place your fingertips gently but firmly on your abdomen at the top of your uterus. When you feel your uterus harden, press on it in several places. If your entire uterus doesn’t feel hard, you’re not having a contraction. (You’re probably feeling your baby’s back pressing against your abdomen.)

4. Time the contractions for one hour. (See page 175.) Note the length and frequency of them.

5. If you have six contractions during the hour while you’re lying down (or four per hour for two hours), call your caregiver. Make sure you tell him or her that you drank two glasses of water and timed your contractions while lying down.

Signs of Preterm Labor

Because some women without any risk factors deliver their babies early, all pregnant women should know the signs of preterm labor. These signs are common and similar to normal pregnancy sensations, so watch for slight differences or changes. While it’s important to be aware of these signs, remember that only about 12 percent of women have preterm labor.

If you have two or more of these symptoms, call your caregiver immediately to help you decide whether you’re in preterm labor.

• Uterine contractions that occur every ten minutes, or six contractions in one hour (Contractions come in waves as your uterus alternately tightens and softens; they don’t have to be painful. See page 136 to learn how to detect contractions.)

• Continuous or intermittent menstrual-like cramps or pressure in your lower abdomen and thighs (pelvic heaviness)

• Dull ache in your lower back that doesn’t go away when you change position

• Intestinal cramping with or without diarrhea or loose stools

• Sudden increase or change in vaginal discharge (watery, blood tinged, or with more thin mucus)

• General feeling that something isn’t right

When checking for preterm contractions, think about your typical uterine activity and remember that contractions of irregular length and frequency are normal in pregnancy. Having persistent, fairly regular contractions for two hours (along with other signs) indicates labor.


For years, researchers have tried to find a reliable method to predict preterm labor. While a single accurate test isn’t yet available, the results of several tests can increase the likelihood of detecting whether a woman at risk for preterm birth will deliver soon. These tests include the following:

• Produced by the baby’s membranes, fetal fibronectin (fFN) is a protein that increases in the last weeks of pregnancy and during labor. When a test detects fFN in vaginal and cervical secretions between the twenty-second and thirty-fifth weeks of pregnancy, the risk of preterm labor is increased (but not guaranteed).

• A transvaginal ultrasound scan or a vaginal exam can determine cervical length, which shows how the cervix is responding to pregnancy. If a woman’s cervix shortens (that is, begins effacing) months or weeks before term without labor contractions, the risk of preterm labor increases.

• Other tests may help identify the risk of preterm labor, including blood tests for specific biochemical markers and a saliva test that looks for an increase of the hormone estriol. (Visit our web site,, for more information on these tests.) However, more research is needed to evaluate the effectiveness of these tests to help prevent preterm labor.


A caregiver diagnoses a woman with preterm labor if an ultrasound scan or a vaginal exam detects the shortening and opening of her cervix. For women pregnant with multiples, because the babies expand the uterus to a size that may naturally cause these cervical changes, caregivers may use additional tests to help determine the risk of preterm birth. Some caregivers offer these tests to all women with signs of labor to determine whether it’s preterm labor. (See above.)


If you have any symptoms of preterm labor, contact your caregiver immediately. Prompt treatment may help stop labor. If your caregiver determines that you’re in preterm labor, he or she may suggest the following measures to try to stop the contractions and prevent a preterm birth:

Go on bed rest.

Bed rest ranges from complete bed rest (getting out of bed only when necessary, such as to use the toilet) to a slight decrease in your activity level plus increased rest. Although research doesn’t show that bed rest reliably stops preterm labor, many caregivers recommend it to decrease uterine activity—and it often seems to work, possibly because your stress levels may decrease when resting. (The relaxing effects of a warm tub bath may also reduce uterine activity.)

Monitor uterine contractions.

If you’re hospitalized for preterm labor, electronic monitoring will determine if labor contractions are progressing. If you’re at home, your caregiver will ask you to continue checking for contractions by hand and to watch for other labor signs. (Portable electronic monitors were used in the past, but because they don’t reduce the rate of preterm birth, their use is rare today.)

Restrict sexual activity (pelvic rest).

Orgasm causes the uterus to contract, and semen contains prostaglandins, which can promote preterm labor in women who are at risk. Nipple stimulation may also initiate preterm labor contractions.

Take medication to help stop or postpone labor.

Caregivers sometimes prescribe drugs to relax the uterus. If the drugs are successful, caregivers usually stop the treatment when the pregnancy reaches about thirty-six to thirty-seven weeks. These muscle relaxants (tocolytics) include nifedipine, magnesium sulfate, and indomethacin. (See page 292.) They stop preterm labor only occasionally, but may delay the birth for up to seven days, providing time to administer other drugs to improve the baby’s health.

Research suggests that progesterone may prevent prematurity when the hormone is injected weekly in women with a prior preterm birth who show signs of cervical changes in the second trimester.

Because certain infections increase the risk of preterm labor, if you have one of these infections, your caregiver may prescribe antibiotics to try to prevent preterm labor contractions.

Consider cervical cerclage (surgical suturing of the cervix).

Incompetent cervix is when the cervix shortens and opens in mid-pregnancy without preterm labor contractions. This relatively rare condition may occur if the cervix has been weakened by injury or surgery, such as conization or a D&C (see page 128) for an abortion. The cervix may be closed with suture thread in early pregnancy as a preventive measure or in mid-pregnancy (before the twenty-fourth week of pregnancy) if cervical changes occur. The sutures are removed in late pregnancy.


If treatment doesn’t stop the contractions or cervical dilation, caregivers may suggest measures to help increase a premature baby’s chances of a healthy life. (See page 292.)

If your baby will be born prematurely, your caregiver may want you to give birth in a hospital with a neonatal intensive care unit (NICU). The survival rate of very premature babies and babies with very low birth weight is greater when they’re born in hospitals that provide intensive care. (See page 293.)

Decreasing Your Risk of Preterm Labor

Although you might not be able to avoid all the risk factors listed on page 136, here are steps you can take to reduce your risk of preterm labor.

1. Attend all prenatal appointments and carefully consider your caregiver’s suggestions. Continue treatment for chronic conditions.

2. Eat well during pregnancy and take any prescribed supplements. Try to reach your suggested weight before becoming pregnant and avoid excessive weight gain during pregnancy.

3. Get screened for infections. If any are detected, have them treated.

4. Avoid smoking, secondhand smoke, alcohol, and hazardous substances.

5. Limit strenuous activities and ask others for help when necessary.

6. Decrease job or life stresses as much as possible. Report any abuse and increase your emotional support from trusted friends and family.

Complications with the Placenta

A few women develop problems with how and where the placenta attaches to the uterus. The following sections discuss the two most common of these placental complications.


Less than 1 percent of pregnancies develop placenta previa, a condition in which the placenta lies completely or partially over the cervix. Women with placenta previa can’t deliver their babies vaginally; instead, they have planned cesarean births, usually after the thirty-sixth week of pregnancy, but before labor begins.


In early pregnancy, you may learn from an ultrasound scan that your placenta attached to the lower part of your uterus near the cervix (low-lying placenta).

In most cases, as your uterus grows, the site where the placenta attached rises away from the cervix. (If you don’t have a low-lying placenta in early pregnancy, you won’t develop placenta previa later.) Your caregiver will diagnose you with placenta previa only if a transvaginal ultrasound scan confirms that the placenta continues to cover the cervix later in pregnancy.

Risk factors for placenta previa include: a prior cesarean birth, uterine surgery, or abortion; uterine abnormalities; an age older than thirty-four; many previous pregnancies; and heavy smoking. The most common symptom of placenta previa is painless vaginal bleeding as cervical changes occur in the last trimester. Bleeding is usually intermittent and ranges from light to heavy. As with any vaginal bleeding during pregnancy, notify your caregiver immediately.

Treatment depends on your symptoms and includes measures to prevent heavy bleeding and decrease the risk of preterm birth. If you haven’t had any bleeding, your caregiver will avoid doing vaginal exams and will advise you to avoid sex and heavy exertion. You may be put on bed rest. If you’ve had vaginal bleeding, you may be hospitalized for close observation and, if blood tests show severe blood loss, have a blood transfusion.


Another rare condition that occurs in about 1 percent of pregnancies is placental abruption, in which the placenta partially or almost completely separates from the uterine wall during the third trimester or during labor. The condition can cause significant blood loss in the mother and can deprive the baby of adequate oxygen. Your risk of placental abruption increases if you have any of the following factors:

• Extremely high blood pressure

• More than five previous pregnancies

• A history of second trimester bleeding

• A prior abruption

• Habit of heavy smoking or cocaine use

• Severe abdominal trauma

Placental abruption may cause any or all of the following symptoms: vaginal bleeding, continuous severe abdominal pain, lower back pain, tender abdomen, and constant tightening of the uterus. Sometimes, vaginal bleeding is absent if the blood collects high in the uterus.

An ultrasound scan may help determine the degree of separation and its effect on blood flow to the placenta. Assessing the mother’s blood pressure and the baby’s heart rate helps estimate the severity of the abruption and, along with tests to check how well the mother’s blood clots, help determine appropriate treatment. When the abruption is small and the baby remains healthy, bed rest and close observation may be the only treatment. If bleeding is severe and the baby’s heart rate shows distress (and if the baby’s chances of surviving a preterm birth are high), a woman has an immediate cesarean birth and a blood transfusion if necessary.

High Blood Pressure and Gestational Hypertension

Your activity level, emotional state, and body position can affect your blood pressure. It’s usually lower when you’re at rest, lying down, or free of emotional stress. It’s usually higher when you’re active, upright, or stressed. Short-term changes in your blood pressure are normal; however, blood pressure that stays too high can cause health risks at any age.

Someone with high blood pressure (hypertension) has had at least two consecutive readings that are over 140/90. The condition, which affects about 10 percent of pregnant women in the United States, can be chronic or develop during pregnancy. When high blood pressure first appears after the twentieth week of pregnancy and remains high for several readings, it’s called gestational hypertension or pregnancy-induced hypertension (PIH).

A pregnant woman with high blood pressure is at risk for serious problems with uterine and placental blood flow and possible damage to other internal organs. Reduced blood flow to the placenta can result in less oxygen and fewer nutrients for the baby and may cause growth problems. Both chronic hypertension (high blood pressure present before pregnancy) and gestational hypertension can cause these problems. Gestational hypertension can also develop into a more dangerous condition called preeclampsia.


Preeclampsia (previously called “toxemia”) is a multi-organ condition with mild to severe symptoms that affects about 5 to 8 percent of pregnancies. It typically occurs after the twentieth week of pregnancy, and the first signs are gestational hypertension and proteinuria (protein in the urine).

Mild preeclampsia developed near term may cause fewer health problems than the possibly serious consequences of severe preeclampsia that begins before the thirtieth week of pregnancy.3 With early diagnosis and aggressive treatment, complications from preeclampsia are generally minimal and both the mother and baby are typically healthy at birth and afterward.

Risk Factors for Preeclampsia

Although the causes of preeclampsia aren’t well understood, a combination of factors appears to trigger the condition. Some women are at higher risk of developing preeclampsia than others are. The most significant risk factors include the following:

• First pregnancy

• Preeclampsia in a previous pregnancy (or a close family member with it)

• Personal history of chronic hypertension, diabetes, kidney disease, polycystic ovarian syndrome (PCOS), or vascular disease

• Obesity

• Age older than thirty-five or younger than eighteen

• Pregnant with multiples

• African descent

• History of certain autoimmune disorders, such as lupus or rheumatoid arthritis

• Infections during this pregnancy, such as periodontal disease or urinary tract infection (UTI)

Researchers continue to seek ways to evaluate a woman’s risk of developing severe preeclampsia. Because it’s a complex condition, a complete risk assessment may include a combination of tests, such as blood and urine tests, and uterine blood flow studies.

Learning More about Pregnancy Complications

To learn more about a specific disease or condition, ask your caregiver for patient-education handouts that describe your condition or disorder. If handouts aren’t available, ask where you can get more information.

You can also search the Internet for web sites that provide information about your condition or concern. To ensure the information on a web site is accurate and up to date, check several sites to compare data. Also check the expertise of site authors and find out whether the sources they cite are reliable or biased. Examples of reliable web sites that provide accurate information on a number of pregnancy complications include the following:





Other Signs of Preeclampsia

Two screening tests can detect early signs of preeclampsia. A urine test will show proteinuria, and routine blood pressure checks will discover high blood pressure. A pregnant woman can often notice other signs of preeclampsia. If you have any of the following signs, contact your caregiver immediately.

• Sudden puffiness (edema) in your hands or face

• Rapid weight gain (more than 2 pounds in one week)

• Headache

• Visual changes or problems (flashes or spots before the eyes or blurred vision)

• Pain in your stomach (epigastric pain) or your right side under your ribs, or possible pain in your shoulder or lower back

It’s possible—but rare—that a woman with preeclampsia will have high blood pressure and proteinuria and have none of the other symptoms. A particular sign of preeclampsia usually indicates the specific organ system affected. Typically, the more systems that are affected, the more severe the condition is. Severe preeclampsia can cause the following complications:

• Placental abruption (See page 140.)

• The HELLP syndrome (hemolysis, elevated liver enzymes, low platelets), which indicates blood and liver complications

• Eclampsia, which indicates neurological irritability and imminent convulsions

• Seizures, stroke, coma, or even death of mother and baby (in the most severe cases)

Treating Preeclampsia

If you have preeclampsia, the only cure is the birth of your baby (normal blood pressure usually returns within days or weeks after the birth). However, treatment to avoid further complications is available, based on the severity of the disease and your baby’s gestational age and health.

If your symptoms are mild (such as blood pressure over 140/90, proteinuria, and fluid retention), treatment usually includes decreased activity or bed rest, blood pressure checks, and close observation. You may receive medications to lower your blood pressure or to reduce the risk that hypertension will slow your baby’s growth.

If you have severe preeclampsia (blood pressure over 160/110 and proteinuria accompanied by liver, blood, or neurological complications), you’ll be hospitalized and given drugs, such as an antihypertensive and magnesium sulfate, to reduce your risk of seizures. (Visit our web site,, for more information on these medications.) You’ll likely continue to receive magnesium sulfate for at least twenty-four hours after the birth to prevent seizures.

If severe symptoms worsen or don’t sufficiently improve with treatment, your caregiver may suggest inducing labor or performing a planned cesarean. If you’re concerned how a preterm birth will affect your baby, you may want to postpone induction. If your health or your baby’s life isn’t in jeopardy, your caregiver may suggest delaying the birth for a day or two so you can receive corticosteroids to promote your baby’s lung development before birth.


Research suggests that for women at risk of developing preeclampsia, taking a low-dose aspirin (50 to 150 milligrams) each day helps reduce the risk and may decrease the rate of perinatal death and increase babies’ birth weight. Check with your caregiver before taking aspirin.4 In addition, studies on folic acid supplementation in the second trimester show a reduced risk of preeclampsia in women who took the supplements in this period.5

Early detection helps decrease the risk of developing severe preeclampsia and other serious complications. Strive to eat a healthful diet and gain a moderate amount of weight in pregnancy. (See page 117.) Attend all prenatal appointments, have the appropriate screening tests, and work with your caregiver to control high blood pressure and treat other early signs of preeclampsia. If you contract any infection, consult your caregiver for early treatment. Infection may increase your risk of preeclampsia.

Diagnostic Tests

Caregivers routinely use screening tests in pregnancy to assess the health of the mother and baby. (See page 67 and visit our web site,, to learn more about screening tests.) If a screening test shows a potential problem or if you have symptoms of a specific pregnancy complication, your caregiver may suggest a diagnostic test to confirm that you have a problem and to detect its severity. Because the results from one test might not be completely accurate, your caregiver may order several tests to confirm a diagnosis.

Some diagnostic tests have more risks than others. Asking key questions about a test can help you learn its risks and benefits, and knowing this information will help you decide whether to have the test. (See page 10.)

The following sections describe common diagnostic tests. The tests in each section share a common purpose, and they’re discussed by order of frequency, starting with the ones most commonly used. For more information on these and other diagnostic tests, visit our web site.


The following tests can provide helpful information if it’s important for you to know in advance whether your baby has a specific genetic problem. However, you may choose not to have these invasive tests because they require penetrating your uterus. Although rare, potential risks of these tests include miscarriage, infection, bleeding, or leaking of amniotic fluid.


Between the fifteenth and twentieth weeks of pregnancy, a laboratory can test a sample of amniotic fluid to help detect Down syndrome, sickle cell anemia, neural tube defects, and other disorders. The results are available in about two weeks. Your caregiver also can use amniocentesis in late pregnancy to assess your baby’s lung maturity before a preterm birth.

Chorionic villus sampling (CVS)

This test examines a small piece from the chorionic villi (the early placenta) to provide information about chromosomal abnormalities in your baby. CVS can be done between the tenth and twelfth weeks of pregnancy.

Cordocentesis or percutaneous umbilical blood sampling (PUBS)

This test assesses a sample of your baby’s blood from the umbilical cord to detect chromosomal defects, blood disorders, and conditions such as infection, anemia, and lack of oxygen. PUBS can be done after the eighteenth week of pregnancy. Because the test carries more risks than amniocentesis, caregivers use it only when they need confirmation of a diagnosis more quickly than amniocentesis can provide.


The following tests allow a noninvasive look at your baby and uterine structures. Except for x-ray, they pose no significant risks to you or your baby.

Ultrasound scan

An ultrasound scan helps estimate your baby’s gestational age and maturity, locates her organs and structures, and detects her presentation and position in the uterus. It also can determine preterm cervical changes and assess amniotic fluid volume when evaluating your baby’s well-being. Caregivers often use ultrasound scans in conjunction with other procedures such as external version of a breech baby, CVS, and amniocentesis. (For information about an ultrasound scan as a screening test, see page 68.)


Magnetic resonance imaging (MRI)

Visual images of the internal structure of your baby can help confirm malformations. MRI also helps assess your internal organs for potential complications. Your caregiver may use MRI when the results of an ultrasound scan are unclear.

Doppler arterial blood flow studies (velocimetry)

A Doppler ultrasound unit placed on your abdomen provides information about the circulation of blood within and among the uterus, placenta, and your baby. Your caregivers may use this test to identify if your baby is at risk for blood flow complications such as intrauterine growth restriction (IUGR), anemia, and prematurity from severe preeclampsia.


Caregivers rarely use an x-ray on pregnant women. If necessary, however, it can help diagnose problems you may have, such as pneumonia, dental disease, and broken bones.


Although the following tests help assess your baby’s well-being by monitoring his heart rate, their results are sometimes difficult to interpret and may lead to more testing.

Non-stress test (NST)

By monitoring your baby’s heart rate when he’s actively moving, your caregiver can better predict his well-being and determine whether a high-risk pregnancy can continue. (See page 252 for more information on fetal heart rate monitoring.) If the results aren’t reassuring, your caregiver may use other diagnostic tests to confirm your baby’s well-being.

Biophysical profile (BPP)

To assess your baby’s well-being, this test considers information from an NST and uses an ultrasound scan to evaluate amniotic fluid volume and your baby’s functions. Your caregiver can use BPP to assess if a high-risk or post-date pregnancy can safely continue or if induction should be considered. Because this test monitors five factors (but not your baby’s size), it’s a fairly good indicator of his condition.

Contraction stress test (CST) or oxytocin challenge test (OCT)

For this test, your caregiver induces contractions and monitors your baby’s heart rate to predict whether he can withstand the stress of labor contractions (if not, a cesarean may be necessary). It’s not usually done unless an NST indicates a problem.


The following laboratory tests offer information that helps your caregiver make an accurate diagnosis and choose appropriate treatment.

Glucose tolerance test (GTT)

For this test, you first have your blood drawn, then you drink a sugary beverage and have blood drawn again every hour in a three-hour period. Your caregiver will diagnose gestational diabetes mellitus (GDM) if a screening test suggests the presence of the condition.

Vaginal or cervical smear

During a vaginal exam, your caregiver obtains secretions from your vagina or cervical area to detect infectious organisms, premature rupture of membranes, or substances that indicate an increased risk of preterm labor.

Key Points to Remember

• Most pregnancies don’t develop complications, and both the mother and baby are healthy at birth and afterward.

• With appropriate prenatal care and self-care during pregnancy, you can decrease your chances of developing serious problems from a chronic condition or from a complication that arises during pregnancy.

• Promptly contact your caregiver if you see any warning signs of pregnancy complications (see page 70). Early treatment helps minimize the severity of any complication.

• Before making decisions about prenatal tests and procedures, be sure you understand how and why they are being done and the benefits, risks, and possible alternatives. Talk to your caregiver and ask questions until you feel that you can make an informed decision. Also, visit our web site,, to learn more information about a specific test or procedure.