Mayo Clinic Guide to a Healthy Pregnancy: From Doctors Who Are Parents, Too!



active labor. Phase of labor, often accompanied by strong contractions, when the cervix dilates from 4 centimeters (cm) to 10 cm.

afterbirth. The placenta and membranes discharged from the uterus after childbirth.

afterbirth pains (afterpains). Uterine contractions that help control bleeding.

alpha-fetoprotein (AFP) test. Tests for a specific protein produced by the fetus but not present to any degree in nonpregnant people. Levels of this protein have implications for the baby’s well-being.

amniocentesis. A test in which a small amount of amniotic fluid is removed from the mother. Used to detect various genetic characteristics, evidence of infection or lung maturity of the unborn baby.

amniotic sac (bag of water). Sac formed by two thin membranes that contains watery fluid (amniotic fluid) and the fetus. The membranes either rupture spontaneously during labor or may be ruptured to hasten labor.

anemia. Condition in which the blood has too few red blood cells. It can cause fatigue and lowered resistance to infection.

anencephaly. Neural tube defect that results in the abnormal development of the baby’s brain and skull.

antibodies. Protein substances that the body makes to help protect itself against foreign cells and infections.

Apgar score. Rating, or score, given to a newborn at one and five minutes after birth to assess color, heart rate, muscle tone, respiration and reflexes.

apnea. Cessation of breathing.

areola. Circular, pigmented area around the nipple of the breast.

asphyxia. Loss of consciousness due to a lack of oxygen, a buildup of carbon dioxide and a low pH.

assisted birth. Delivery assisted by medical intervention, such as an episiotomy, forceps-assisted birth or vacuum-assisted birth.

assisted reproductive technologies. Medical intervention that aids conception, such as in vitro fertilization.


baby blues. Period of low mood, occur- ring in a number of new mothers.

biochemical testing. Chemical analysis of blood or amniotic fluid to detect a fetal condition. Examples include alpha-fetoprotein, estriol, inhibin and pregnancy-associated plasma protein A testing.

biophysical profile. Assessment of fetal status based on heart rate testing and ultrasound findings.

birth plan. Written or verbal guide that explains how you wish to deliver your baby.

blastocyst. Rapidly dividing fertilized egg that enters the uterus and has cells committed to placental and fetal development.

bloody show. Blood-tinged mucous discharge from the vagina either before or during labor.

bradycardia. Sustained period during which the heart rate is slower than normal.

Braxton Hicks contractions. Irregular uterine contractions that don’t result in changes in the cervix. Also called false labor.

breech position. Baby is positioned with feet or bottom toward the cervix at the time of birth.


cephalopelvic disproportion. Circumstance in which baby’s head is too large for the mother’s pelvis.

cervical incompetence. Condition

in which the cervix begins to open without contractions before the

pregnancy has come to term; a

cause of miscarriage and preterm delivery in the second and third trimesters.

cervix. Neck-like lower part of the uterus, which dilates and thins during labor.

cesarean birth. Birth in which an incision is made through the abdominal wall and uterus to deliver the baby. Also called cesarean section, or C-section.

chorionic villus sampling (CVS). Procedure that removes a small sample of chorionic villi from the placenta where it joins the uterus, to test for chromosomal or other abnormalities.

circumcision. Procedure on male infants that removes the foreskin from the penis.

colostrum. Yellowish fluid produced by the breasts until the mother’s milk “comes in”; usually noticed in the latter part of pregnancy.

congenital disorder. Condition that a person is born with.

contraction stress test. One of several tests to evaluate the condition of the fetus and its placenta. It measures the fetal heart rate in response to contractions of the mother’s uterus.

contractions (labor pains). Tightening of the uterine muscles.


deep vein thrombosis (DVT). Blood clot inside a vein, which is a potential complication of childbirth.

dilation. Indicates the diameter of the cervical opening and is measured in centimeters (cm); 10 cm is fully dilated.

Doppler. Device with which a doctor can hear a fetal heartbeat by about the 12th week.

dystocia. Difficult labor for any reason.


early (latent) labor. Earliest phase of childbirth, during which uterine contractions gradually change the cervix. This phase is generally over when the cervix reaches 4 cm dilation.

ectopic pregnancy. Pregnancy that occurs outside the uterus; the most common variety is tubal pregnancy.

effacement. Progressive thinning of the cervix as its connective tissue is drawn up around the baby’s head; 100 percent indicates total effacement.

embryo. Fertilized ovum from shortly after the time of fertilization until eight weeks.

endometrium. Lining of the uterus, in which the fertilized egg embeds itself.

epidural. Anesthetic method used to decrease or eliminate discomfort during labor; sometimes called an epidural block.

episiotomy. Surgical incision in the perineum to enlarge the vaginal opening.

external version. Doctor’s attempt to turn a poorly positioned baby into a better birthing position.


fallopian tubes. Structures that pick

up the egg as it’s released from the ovary while simultaneously propelling sperm toward its end where fertilization can take place. The fertilized egg is delivered to the uterus through these tubes.

fetal fibronectin. Substance held between the fetal membranes and uterine wall that can be tested to assess the risk of preterm delivery.

fetus. Name for unborn baby after the first eight weeks of pregnancy.

follicle-stimulating hormone. Hormone that fosters the development of eggs in the ovaries.

fontanels. Soft spots on a baby’s head where the skull hasn’t fused together. The spots close about six weeks to 18 months after birth.

forceps. Obstetrical instrument that fits around the baby’s head to guide the baby through the birth canal.

fundal height. Distance from the top of the uterus to the pubic bone; used to assess fetal growth in the uterus.


genetic disorder. Condition that a person can pass on to offspring, which he or she may have acquired from a parent.

gestational diabetes. Form of diabetes that develops during pregnancy, resulting in improper regulation of glucose levels in the blood.

glucose challenge test. Test that screens for gestational diabetes by measuring your blood sugar (glucose) level after drinking a glucose solution.

group B streptococcus (GBS). Bacterium that’s part of the genital tract in many women, but can cause severe infection in newborns if passed to the baby during birth.


human chorionic gonadotropin (HCG). Hormone produced by the placenta. Its measurement is key to all pregnancy tests.

human placental lactogen (HPL). Hormone that alters your metabolism to make nutrients available for your baby and stimulates your breasts to produce milk.

hydramnios, or polyhydramnios. Excess of amniotic fluid.

hypoglycemia. Condition in which the sugar (glucose) concentration in the bloodstream is lower than normal.


induction of labor. Artificially starting labor, usually by administering medication or breaking the bag of water.

intrauterine growth restriction (IUGR). Significant slowing of fetal growth.

in vitro fertilization (IVF). Process by which eggs and sperm are combined in an artificial environment outside the body, then transferred back into a woman’s uterus to grow.


jaundice. Yellow tinge to the skin and whites of the eyes caused by too much bilirubin in the bloodstream.


Kegel exercises. Exercises done to strengthen pelvic floor muscles.


labia. Sets of skin folds that surround the opening to the vagina and urethra.

Lamaze. Techniques used by the mother in childbirth to reduce pain and the use of medications during birth.

lanugo. Fine, downy hair growing on the skin of a fetus by about week 26.

lightening. Repositioning of baby lower in the mother’s pelvis. It may occur several weeks or just prior to labor onset.

lochia. The discharge of blood, mucus and tissue from the uterus during the first few weeks after childbirth.

luteinizing hormone. Pituitary hormone that causes an ovarian follicle to swell, rupture and release an egg.


macrosomia. Larger than normal birth weight, usually more that 9 pounds 12 ounces.

mastitis. Infection that occurs when bacteria enter the breast.

meconium. Product of a baby’s first bowel movements, characteristically green in color.

meconium aspiration. A newborn in- hales amniotic fluid mixed with meconium, which may cause inflammation and airway blockage.

miscarriage. Premature, spontaneous termination of a pregnancy.

molding. Temporarily flat, crooked, elongated or pointy shape of the bones of the baby’s skull while passing through the birth canal.

mucous plug. Collection of mucus that blocks the cervical canal during pregnancy to prevent entrance of germs into the uterus. The plug passes (bloody show) when the cervix starts to thin and open.


neonatologist. Physician with advanced training in the diagnosis and treatment of newborn disorders.

neural tube. Structure in the embryo that develops into the brain, spinal cord, spinal nerves and backbone.

nonstress test. Test that helps a doctor examine the condition of a fetus by measuring the heart rate in response to his or her own movements.


occiput posterior position. Position

in which baby faces the mother’s abdomen during delivery rather

than the preferred position of facing the back.

ovulation. Release of an egg from the ovary. Fertilization can occur only within a day or two of ovulation.


pelvic floor muscles. Muscles at the base of the pelvis that support the bladder, urethra, rectum, and vagina and uterus in women.

perinatologist. Obstetrician who specializes in diagnosis and treatment of pregnancy problems.

perineum. Area between vaginal and anal openings in women.

pica. Uncommon craving to eat nonfood items such as laundry starch, dirt, baking powder or frost from the freezer; suggests an iron deficiency.

placenta. Circular, flat organ that’s responsible for oxygen and nutrient exchange and elimination of wastes between mother and fetus.

placenta accreta. Abnormal placental attachment in which the placenta adheres too firmly to the uterine wall.

placenta previa. Abnormal location of the placenta in which it partially or completely covers the cervix.

placental abruption. Separation of the placenta from the inner wall of the uterus before delivery.

postpartum depression. Type of depression that can afflict a mother between two weeks and six months after a baby is born.

preeclampsia. Disease occurring during pregnancy marked by hypertension and protein in the urine.

premature labor, or preterm labor. Contractions that start opening the cervix before week 37.

progesterone. Hormone that inhibits the uterus from contracting and promotes the growth of blood vessels in the uterine wall.

prostaglandin. Chemical produced by the uterine lining and fetal membranes at or near the onset of labor.

pudendal block. Anesthetic injected into the vaginal wall to prevent pain during delivery, or during repair of vaginal tears or an episiotomy.


quickening. Mother’s first perception

of fetal movements, usually felt between weeks 18 and 20 for first-time mothers, but often earlier in women with a prior pregnancy.


regional anesthesia. Numbness in a certain area of the body, induced by an anesthetic.

relaxin. Hormone produced by the placenta that softens connective tissues, which allows the pelvis to open wider during childbirth.

respiratory distress syndrome (RDS). Difficulty in breathing, caused by lack of surfactant in premature babies.

retained placenta. Failure of the placenta to expel itself within 30 minutes after birth.

Rh immunoglobulin (RhIg). Drug used in Rh negative women to prevent their immune system from recognizing Rh positive blood.

rhesus (Rh) factor. Red blood cell pro- tein similar to the proteins that deter- mine blood types A, B and O. You’re either Rh positive or Rh negative.


sciatica. Temporary condition caused by extra pressure on one or both sciatic nerves, causing pain, tingling or numbness in your buttocks, thighs and lower legs.

spina bifida. Spinal defect that

results in failure of the vertebrae

to fuse. It can occur in any vertebra but is most commonly found in the lower spine.

spinal block. Anesthetic technique in which medication is injected into the fluid surrounding the spinal nerves.

station. Measurement of the descent of a fetus in the birth canal.

stillbirth. Delivery of a baby who has died in the uterus.

surfactant. Substance covering the inner lining of the air sacs in the lungs that allows the lungs to expand normally during breathing.


teratogens. Agents that cause defects in a developing fetus, such as alcohol, certain medications, pollutants and recreational drugs.

transient tachypnea (wet lung). Mild, temporary respiratory condition of newborns characterized by rapid breathing.

transition. Portion of active labor in which contractions are most intense, typically between 7 centimeters and complete dilation.

transverse lie. Position in which a baby lies crossways in the uterus before birth. It is incompatible with a vaginal delivery.

twin-twin transfusion. Passage of blood from one identical twin to the other through connections of blood vessels within the placenta.


umbilical cord. The tubular structure that carries the fetal blood to the placenta, where oxygen and nutrients can be delivered and waste products removed.

umbilical cord compression. A complication in which the umbilical cord becomes compressed or pinched, which may cause blood flow to and from the baby to the placenta to slow or even stop.

umbilical cord prolapse. A complication in which the umbilical cord slips out through the opening of the cervix, often followed by compression of the cord by the baby’s presenting part.

uterine atony. The lack of muscle tone in the uterus after birth, preventing contractions needed to control bleeding from the placental site.

uterus (womb). The female organ in which the unborn baby develops.


vacuum extractor. A tool with a rubber or plastic cup that can be held gently to the baby’s head, providing suction that can aid in the baby’s delivery.

vernix caseosa, or vernix. A slippery, white, fatty substance covering the skin of a fetus.


zygote. The result of the union of an ovum and sperm; a fertilized egg before it begins to divide and grow.