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

CHAPTER 7. Month 4: Weeks 13 to 16

We made it through the first trimester. What a relief! My husband and I now feel more comfortable telling people that we’re expecting a baby. My tummy is already starting to show a little, too, which is fun. And I feel better. I have more energy, and I’m not so nauseated and dizzy. — Amy

One down and two to go! The beginning of the second trimester is generally a time of relief for most pregnant women. You’ve made it past the first three months — the stage of pregnancy when pregnancy loss is most common. You’re also at the point when those early pregnancy symptoms — fatigue and nausea — should start subsiding.

The second trimester is often considered the easiest stage of pregnancy because this is when most women feel their best. So, enjoy this time. Get out and do the things you love. You might even want to take a vacation or plan some outings. Face it, you’ve earned it!


As you enter the second trimester, all of your baby’s organs, nerves and muscles are formed and beginning to function together. Growth continues at a rapid pace, but baby is still small at this point — less than 3 ounces.

Week 13 Your baby’s eyes and ears are now clearly identifiable, although the eyelids are fused together to protect the developing eyes. They won’t reopen until about your 30th week. Tissue that will become bone is developing around your baby’s head and within the arms and legs. If you were able to sneak a peek at your baby this week, you might see some tiny ribs.

Your baby is now able to move his or her body in a jerky fashion, flexing the arms and kicking the legs. But you won’t be able to feel these movements until your baby grows a bit larger. Your baby may be able to put a thumb in his or her mouth, but sucking will come later.

Week 14 Your baby’s reproductive system is the site of most of the action this week. If you’re having a boy, his prostate gland is developing. If you’re having a girl, her ovaries are moving down her abdomen into her pelvis. In addition, because the thyroid gland is now functioning, your baby starts producing hormones this week. By the end of this week, the roof of your baby’s mouth (palate) will be completely formed.

Week 15 Eyebrows and hair on your baby’s scalp are starting to appear this week. If your baby is going to have dark hair, the hair follicles may begin making the pigment that will give the hair its dark color.

Your baby’s eyes and ears now have a baby-like appearance, and the ears have almost reached their final position, although they’re still riding a little low on the head. Your baby’s skin is adding hair follicles and accessory glands, but it is still very thin.

The bone and marrow that make up baby’s skeletal system continue to develop this week. Muscle development is continuing, too. By the end of the week, your baby will be able to make a fist.

Week 16 The skeletal and nervous system have made enough connections to signal movements of the limbs and body. In addition, your baby’s facial muscles are now well enough developed to allow for a variety of expressions. Inside your uterus, your baby may be squinting or frowning at you, although these movements aren’t conscious expressions of emotions.

Your baby’s skeletal system continues to develop as more calcium is deposited on the bones. If you’re having a girl, millions of eggs are forming in her ovaries this week. Beginning at 16 weeks, your baby’s eyes are sensitive to light.

Although you probably don’t even know it, your baby may be having frequent bouts of the hiccups. Hiccups often develop before your baby performs lung movements associated with breathing. Because your baby’s trachea is filled with fluid rather than air, the hiccups don’t make that characteristic hiccup sound.

At 16 weeks into your pregnancy, your baby is between 4 and 5 inches long and weighs a bit less than 3 ounces.


This week begins what’s sometimes called the golden period of pregnancy. The name is apt. The side effects of early pregnancy taper, but the discomforts of the third trimester haven’t yet begun. Plus, your risk of miscarriage is now greatly reduced. New sensations also are common during this time.

What’s happening and where The changes that began in your first weeks of pregnancy are increasing and accelerating — and becoming more obvious to others. Your hormone levels continue to increase this month, influencing the growth of your baby and affecting every organ system in your body. Here’s an overview of what’s happening.

Heart and circulatory system Your circulatory system continues to expand rapidly, and the result is a lowering of your blood pressure. During the first 24 weeks of your pregnancy, your systolic blood pressure (top number) will probably drop by five to 10 points, and your diastolic blood pressure (bottom number) by 10 to 15 points. After that they’ll gradually return to pre-pregnancy levels. Be aware that you may experience dizziness or faintness during hot weather or when you’re taking a hot bath or shower. This happens because heat makes the tiny blood vessels in your skin dilate, temporarily reducing the amount of blood returning to your heart.

Your body continues to make more blood this month. Right now, the extra blood you’re producing is mostly plasma, the fluid portion of blood. During the first 20 weeks of pregnancy, you produce plasma more quickly than you produce red blood cells. Until your red blood cells have a chance to catch up, they’re outnumbered, resulting in lower concentrations.

If you don’t get the iron you need this month to help your body make more red blood cells, you may become anemic. Anemia results when you don’t have enough red blood cells in your blood and, therefore not enough of the protein hemoglobin to carry oxygen to your body’s tissues. Anemia can make you tired and more susceptible to illness, but unless the anemia is severe, it’s unlikely to hurt your baby. Pregnancy is designed so that even if you’re not getting enough iron, your baby is.


The increased blood flow throughout your body may be causing some new unpleasant side effects in your nose and gums — congestion troubles resulting from extra blood flowing through your veins and arteries.

Your nasal tissues may be swollen and fragile. And your nasal membranes may be producing more mucus, resulting in nasal stuffiness. You may also experience nosebleeds, even if you never did before. And don’t be surprised to find your gums bleed when you brush your teeth. Many pregnant women experience gum softening or bleeding. None of these problems will harm you or your baby.

Respiratory system Stimulated by the hormone progesterone, your lung capacity is increasing this month. With each breath, your lungs are inhaling and exhaling up to 30 to 40 percent more air than they did before. These changes are allowing your blood to carry large quantities of oxygen to your placenta and baby. In addition, they’re allowing your blood to remove more carbon dioxide from your body than normal.

You may notice that you’re breathing slightly faster these days than before you became pregnant. You may also start experiencing shortness of breath. Two-thirds of all pregnant women do, usually beginning around the 13th week of pregnancy. This is because your brain is decreasing the carbon dioxide level in your blood in order to make it easier to transfer more carbon dioxide from your baby to you. To do this, the brain adjusts your breathing volume and rate.

To accommodate your increased lung capacity, your rib cage will enlarge over the course of your pregnancy, by 2 to 3 inches in circumference.

Digestive system Increased amounts of the hormones progesterone and estrogen tend to relax smooth muscles in your body, including your digestive tract. The result is a slowing down of your digestive system. The movements that push swallowed food from your esophagus down into your stomach are slower, and your stomach also is taking longer to empty.

The slowdown is designed to allow nutrients more time to be absorbed into your bloodstream and reach your baby. Unfortunately, when you combine it with an expanding uterus crowding out other organs in your abdomen, the slowdown can also cause heartburn and constipation, two of the most common and uncomfortable side effects of pregnancy. You may begin experiencing these side effects this month. About half of all pregnant women experience heartburn. The story is much the same with constipation, which also affects at least half of all pregnant women.

Breasts Your breasts and the milk-producing glands inside them continue to grow in size this month, stimulated by increased production of estrogen and progesterone. Darkening of the skin around your nipples (areolas) may be especially noticeable now. Although some of this increased pigmentation will fade after you’ve given birth, these areas are likely to remain darker than they were before you were pregnant. Expect your breasts to feel tender or sore and fuller and heavier.

Uterus Now that you’re in your second trimester, your uterus is positioned higher and more forward, which is changing your center of gravity. Without even knowing it, you may be starting to adjust your posture and the ways you stand, move and walk. You may at times feel as if you’re going to tip over. This is normal. You’ll return to your more graceful self after your baby is born.

As your uterus is becoming too big to fit within your pelvis, your internal organs are being pushed out of their usual places. Greater tension is also being placed on your surrounding muscles and ligaments. All this growth may cause some aches and pains.

Because of the pressure your uterus is placing on the veins in your legs, you may experience leg cramps, especially at night. You may also notice that your navel is starting to protrude. This, too, is the result of pressure from your growing uterus. After you deliver your baby, your navel will almost certainly return to it’s normal shape.

You may also experience some pain in your lower abdomen this month. This is probably related to the stretching of ligaments and muscles around your expanding uterus. The stretching doesn’t pose a threat to you or your baby.

Urinary tract The hormone progesterone is relaxing the muscles of your ureters, the tubes that carry urine from your kidneys to your bladder, slowing your flow of urine. In addition, your expanding uterus is further impeding your urine flow. These changes, combined with a tendency to excrete more glucose in your urine, can make you more prone to bladder and kidney infections.

If you’re urinating even more often than normal, feeling burning on urination or experiencing a fever, you may have a urinary tract infection. Report these signs and symptoms to your care provider. Abdominal pain and backache also may signal a urinary tract infection. Recognizing and treating urinary tract infections are especially important during pregnancy. Left untreated, these infections can be a cause of preterm labor later in pregnancy.

Bones, muscles and joints Your bones, joints and muscles are adapting to the stresses of carrying your baby. The ligaments supporting your abdomen are becoming more elastic, and the joints between your pelvic bones are beginning to soften and loosen. Ultimately, these changes will make it easier for your pelvis to expand during labor and childbirth so that your baby can pass through. But for now, the changes may cause some back pain.

The lower portion of your spine may start to curve backward to compensate for the shift in your center of gravity caused by your growing baby. Without this change, you’d probably fall over. This change in your posture also can strain your back muscles and ligaments and cause some back pain.

Vagina You may notice more vaginal discharge this month, caused by turnover of the rapidly growing cells in the vagina. These cells combine with normal vaginal moisture to form a thin, white discharge. Its high acidity is thought to play a role in suppressing the growth of potentially harmful bacteria.

The hormone changes of pregnancy can disrupt the normal balance of organisms in the vagina, causing one type of organism to grow faster than the others. This can cause a vaginal infection. If you have vaginal discharge that’s greenish or yellowish, strong smelling or accompanied by redness, itching and irritation of the vulva, contact your care provider. But don’t be too alarmed. Vaginal infections are common in pregnancy and can be easily and successfully treated.

Don’t use an over-the-counter yeast infection medication without talking to your care provider first. Because other types of vaginal infections can cause signs and symptoms similar to those caused by yeast infections, it’s best for your care provider to determine what type of vaginal infection you have before you start treatment.

Skin A common occurrence of pregnancy is skin darkening. You may be noticing darker areas of skin on or around your nipples, in the area between your vulva and anus (perineum), around your navel, and on your armpits and inner thighs. These changes will be more pronounced if you have dark skin. Skin darkening almost always fades after delivery, but some areas are likely to remain darker than before you were pregnant.

You may also notice mild skin darkening on your face. This condition, called chloasma or the mask of pregnancy, affects about half of all pregnant women, mostly those who have dark hair and fair skin. It usually appears on the forehead, temples, cheeks, chin and nose. It may not be as intense as other changes in pigmentation and it generally fades completely after delivery. When outside, it’s important to use sunscreen, especially on your face. Sun exposure may increase normal skin darkening.

You may also notice redness and itching on the palms of your hands and soles of your feet. This is thought to be caused by increased estrogen production. Some women also experience bluish, blotchy patches on their legs and feet, especially when they’re cold. This skin change is caused by an increase in the hormone estrogen and will disappear after your baby is born.

Weight gain You’ll probably gain about half a pound a week this month, for a total of about 2 pounds. Don’t be surprised if your weight gain varies somewhat, with you gaining more weight one week and less the next.


Now that you’re growing out of your jeans and you’ve been able to hear your baby’s heartbeat, your baby may seem more real to you. Chances are, you also feel better and have more energy. This is all good!

Feeling productive Strike while the iron is hot. While your mood and energy are up, start taking care of the “housekeeping” details of pregnancy. If you’re interested in childbirth classes for you and your partner, now is the time to investigate your options. Now may also be a good time to familiarize yourself with maternity and paternity leave policies.

And, if you haven’t already, this is a good time to think about child care for when you go back to work. You may think it’s too soon, but openings for infant care in some regions and cities can be difficult to find, so it’s best to start looking early.

As you take care of these details, you may find it a little difficult to concentrate. You may even feel a little scatterbrained or forgetful. This is normal, no matter how organized you were (or weren’t) before pregnancy. Take these foggy moments in stride. You’ll be back to your usual self in a few months.


As your belly begins to grow in size, you’ll find that many of your clothes no longer fit or they don’t fit well. You may be able to get by for a few months by wearing your baggie clothes or even some of your husband’s clothes, but soon you’ll have to purchase maternity clothes. The good news is, it’s a great time to be pregnant. Fashions have changed greatly, and today’s maternity clothes are very stylish. You can be pregnant and still look trendy!

Here are some points to keep in mind when you go on that shopping trip:

 Your tummy is just beginning to expand. Don’t buy too much right now. Purchase enough items so that you have what you need, but don’t go overboard. You may want to purchase additional clothes later on.

 Plan ahead. Remember that your belly will grow. If it fits well now, it won’t in a few months. If you want to wear this item for the length of your pregnancy, you need to buy it in a big enough size.

 Think vertical. As you widen, look for clothes with vertical rather than horizontal lines to make you look slimmer. Dark-colored clothes also tend to be more slimming.

 You’re not limited to maternity clothes. You may find that regular clothes in larger sizes will work just as well.


Your visit to your care provider this month will include tracking your baby’s growth, confirming your due date and watching for any problems with your health.

Your care provider may measure the size of your uterus to help determine the baby’s age. This is done by checking what’s called the fundal height — the distance from the top (fundus) of your uterus to your pubic bone. To find the top of your uterus, your care provider may gently tap and press on your abdomen and measure from that point down along the front of your abdomen to your pubic bone.

In addition to performing the fundal height check, he or she may check your weight and blood pressure and ask you about any signs and symptoms you’ve been experiencing. If you haven’t done so already, you may get to hear your baby’s heartbeat using a special listening device called a Doppler.


A very difficult decision for many working women is what they will do once their baby is born. Like many moms-to-be, you may grapple over whether you should return to work or stay home. And if you do go back, should you work full time or part time?

Before the 1960s and ’70s, it was generally expected that women were the primary caregivers of their children. But as more women began to work outside of the home, the desirability and, indeed, the practicality of the stay-at-home-mom arrangement came into question. As more women returned to work, finding child care took a spot on the pregnancy to-do checklist.

If you know that you’ll be returning to work after your child is born, it’s never too early to begin looking for child care. If you’re not sure if you’re going back, it’s probably best to explore your options while you make your decision. Consider these factors:

 Your budget. Know the cost of child care and how it’ll affect your budget. If the expense is prohibitive, get creative. Perhaps you or your partner could adjust work hours or schedules to reduce the need for child care.

 Your expectations. Be open and honest with any prospective child care provider about your preferences and expectations, from discipline to diapers. For example, do you prefer disposable diapers or cloth? If you choose cloth, can the provider accommodate that? What other things are especially important to you?

 Your family dynamics. If a loved one offers to care for your baby, give the offer serious thought. But be prepared for the emotions that can accompany such an arrangement. Your family member may be more than willing to offer you plenty of advice — more advice than you want! You don’t want the arrangement to cause a rift in family relations.

Child care options Child care options vary. For example, some larger companies provide child care on site for their employees. For most women, though, their options include the following:

In-home care Under this arrangement, someone comes to your home to provide child care. The person may live with you, depending on your agreement. Some examples of in-home caregivers are relatives, nannies and au pairs. Au pairs typically come to the United States on a student exchange visa and provide child care in exchange for room and board and usually a small salary. The advantages of hiring an in-home caregiver is that your child can stay at home, you set your own standards, and you have more flexibility. But you also have certain legal and financial obligations as an employer.

Family child care Many people provide care in their homes for small groups of children. Homes that offer child care usually have to meet state or local safety and cleanliness standards. Family child care allows your child to be in a home setting with other children, often at a lower cost than that of an in-home caregiver or a child care center. Quality varies, so it’s important that you visit the home and get references from current or previous clients.

Child care centers Child care centers are organized facilities with staff members who are trained to care for groups of children. These centers are typically required to meet state or local standards. Some of the advantages of child care centers include socialization with other children, a large selection of toys and activities, and they’re fully staffed, which can relieve worries about finding backup care. Child care centers may not let you bring your child if he or she is mildly ill, and they usually require you to be fairly punctual. When considering a center, check the ratio of children to caregiver. If one adult has too many children to care for, your child may not get as much individual attention as you want.

Making your decision Consider all of your options and don’t be afraid to ask questions or go back for a second visit, maybe even a third.

Once you’ve found child care you feel comfortable with, you can return to work with confidence knowing that your child is in good hands. Often, when mothers first return to work after their baby is born, they feel guilty for leaving the child. Or they’re anxious that the child may bond more with the caregiver than with them. But don’t worry, you’ll still have time to spend with your child. The bond between mother and child, and father and child, is unique and can’t be replaced.

Work and family balance It’s hard, if not impossible, to evaluate the effect of a working mother on her child. Results of studies vary. Some studies have found a slightly negative effect on child behavior and mother-child bonding for children whose mothers work during early childhood years. Other child experts assert that participation in high-quality group child care offers children a social setting where they can learn to interact with their peers and other adults.

One thing that research — and common sense — supports is the positive effect of a loving, nurturing relationship between parent and child. The most influential factor in parenting is probably not the sheer quantity of time you spend with your child. Stay-at-home parents don’t spend all of their time interacting with their children. They have errands to run, dishes to wash, clothes to fold and other duties that come with running a household.

Whatever your choice, if you feel happy and fulfilled, it will affect your child. If you resent your arrangement or feel cheated by it, you’ll likely pass on these feelings to your child.

If you’re still uncertain if you should return to work after your baby is born, here are some things to think about. Keep in mind, there is no right or wrong in this decision, but there’s probably a choice that’s best for you. Talk it over with your partner and friends and family who have made different choices. Then make the best decision for you and your family. You may also find that over time, your choice may change, as your circumstances change.

Your financial needs Sometimes women have to work in order to make ends meet. You simply may not have the option of staying at home. Although money isn’t everything, it is necessary to provide basic care for your family. If you need the income, spending some time away from your child is probably preferable to enduring chronic stress over money issues.

If you or your partner makes enough income to sustain your family, you may not feel the need to have both of you split your time between work and home. If the loss of income is more stressful than you imagined, however, you might consider taking on a part-time job or a job that you can do from home.

Your desire to maintain a career Women who’ve worked hard to attain a certain position or whose occupation is meaningful to them often feel reluctant to give it up. You may desire and enjoy the intellectual challenges and adult interaction that come from working outside the home. Because these needs are being met at work, you may feel more prepared to function at home. If you’re happy at work, chances are good you’ll be happy at home.

Your desire to be a full-time parent Just the opposite, perhaps your job is just that — a job. Or perhaps you value your job, but being your child’s primary caregiver is more important to you than keeping your job. If your real desire is to stay at home with your children, see if you can make it work.

Your ability to manage stress It takes energy to handle the juggling act of parenthood and working outside the home. Some people manage the stress that comes with these dual roles just fine. Others struggle with it.

Consider how well you can handle multiple roles and responsibilities. If you work, can you provide your children with the sort of attention you’d like them to have? Will your performance at work and at home decline? Will you have the support of friends and family to help you through some of the more difficult days? An unhappy mom can result in an unhappy household.