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The Third Trimester of Pregnancy

Overview

During the third trimester of pregnancy, from 28 weeks of gestation until your labor and delivery, both you and your baby are going through big changes. The baby is growing and changing in preparation for the transition into the real world. You are changing, both physically and emotionally, to prepare for labor and delivery, and the transition to breastfeeding and caring for your newborn infant. We are here to help you make these transitions safely and smoothly.

Fetal Growth and Development

As you start your third trimester of pregnancy, your baby weighs 1 to 2 pounds and is 8 to 14 inches long. In this trimester, your baby will gain more than three-quarters of its total birth weight.

At 28 weeks:

• Your baby's eyes are able to open and close.
• His or her skin is becoming smooth, and the hair on your baby's head is getting longer.
• The lanugo, a fine, downy hair that once covered the baby, is beginning to disappear.
• The vernix caseosa, a creamy, white substance that protects the skin from long exposure to amniotic fluid, still covers the body.
• The lungs are maturing and your baby is starting to practice breathing. Your baby could probably survive if it were born now, but it will be healthier when born at full term (37 to 42 weeks).

At 32 weeks:

• Your baby will probably weigh 4½ to 7 pounds and measure about 18 inches long.
• Your baby's skin is now smooth because baby fat has filled in the wrinkles.
• Your baby's fingers have complete fingernails.
• The lanugo is gone, except for some on the back and shoulders.
• Vernix caseosa remains only in the skin folds.
• The bones of the head are firm but flexible enough to pass through the birth canal without damage.
• The lungs are often fully developed during this final month.

At birth:

• Your baby may weigh 6 to 9 pounds and measure 19 to 21 inches long.
• He or she will be able to grasp, become startled, sneeze, cough, suck, and blink.
• Your newborn will be able to smell, taste, hear, and feel your touch on his or her skin.
• He or she will be able to clearly see an object about 8 inches away.
• When you're breastfeeding, the distance from your face to your baby's face is about 8 to 10 inches, so it's a perfect time to make eye contact and gently stimulate the baby's other senses through stroking and singing.

The first few weeks after birth are exciting and challenging for both parents and the newborn, who is working hard to achieve a rhythm in his or her new life. We are here to help you make a successful adjustment to being a new parent.

Routine Prenatal Testing and Screening

During your pregnancy, there are many kinds of prenatal tests that can help you learn more about your baby's health. We can discuss your options and decide which tests might be a good option for you.

Routine prenatal tests and screening

These are tests that we recommend for all pregnancies to check the health and development of your baby. These routine prenatal tests are safe for you and your baby. During your third trimester we may recommend tests for:

• Anemia
• Diabetes
• Group B streptococcus (GBS)

We will also recommend a RhoGAM shot if you have an Rh-negative blood type. We do not routinely offer an ultrasound test during your third trimester of pregnancy, but we may recommend one, based on a special medical need.

To protect your newborn from whooping cough, we also recommend that you receive the Tdap vaccine during each pregnancy, preferably between 27 and 36 weeks.  The vaccine is safe for pregnant women. Even if you have already been vaccinated for Tdap, we recommend that you have the vaccine again during the end of your pregnancy because it transfers additional protection to your baby.

Optional prenatal screening

Certain blood tests can help you find out if you have a higher or lower chance of having a baby with certain birth defects, but they can't make a definitive diagnosis. These are optional prenatal tests, and are safe for you and your baby. Serum-integrated screening, sequential integrated screening, and quad tests are examples of optional screening tests. These tests are most effective when done at a certain stage of fetal development. Depending on which trimester you are in, we can discuss which screenings available for you.

Prenatal diagnostic tests

While there is no test that can detect all potential problems, these tests can diagnose certain kinds of birth defects. Prenatal diagnostic tests are more invasive than other prenatal tests, and there is a very small associated risk of miscarriage. Some women choose diagnostic tests based upon their family history, or their age during their pregnancy. Examples of diagnostic tests are amniocentesis and chorionic villus sampling.

Benefits of Breastfeeding

Breast milk is the perfect food for your baby. There are many health benefits for you and your baby. According to the American Academy of Pediatrics, breast milk is the only food that your baby will need during the first 6 months of life. We recommend that you continue to breastfeed your baby for up to 1 year if you are able to. Even after you introduce solid foods, you can continue breastfeeding for as long as you wish.

Breastfeeding decreases your baby's risk for many types of infections and allergies. Benefits include:

• Fewer ear infections
• Less risk of respiratory infections and asthma
• Fewer urinary tract infections
• Less diarrhea and constipation
• A lower chance of childhood obesity
• A lower risk of certain childhood cancers
• Improved development of the baby's immune system
• Better digestion
• Improved brain growth

Benefits to you may include:

• More rapid recovery from your delivery
• Decreased blood loss after delivery if you breastfeed immediately after the baby is born
• More rapid loss of pregnancy weight
• Increased sense of well-being
• More opportunity for mother-baby bonding
• No need for preparation, heating, refrigeration, or sterilization of breast milk and a significant cost savings when compared to formula

There are rare medical conditions where breastfeeding is not advised. We can talk further if this applies to you.

Preparing for Breastfeeding

You and your baby will be more successful at breastfeeding if you are prepared. You can begin preparing now and continue throughout the last weeks of pregnancy. Suggestions for how to prepare include:

Learn all you can about breastfeeding

Take a class, read a book, or read our article on breastfeeding for more information. Talk to women who've had successful breastfeeding experiences. Remember, breastfeeding is a learned skill and takes practice.

To locate classes near you, search our health class directory or contact your local Health Education Center or department.

Think about how long you would like to breastfeed

Breastfeeding does take time, but it is time well spent. You're giving your baby the best possible food, holding your baby close, and making a strong connection. Breast milk is the best food for your baby and has all the nutrition your baby needs for the first 6 months of life. The longer you breastfeed, the greater the benefits will be for you and your baby.

Make a list of breastfeeding resources

Get phone numbers of hospital lactation consultants, your local Pediatric Department, or members of your local La Leche League. Have these numbers ready so you can call after you and your baby go home from the hospital. For breastfeeding questions, call the 24-hour helpline at 877-4-LALECHE.

Learn about expressing your milk

Expressing and storing your breast milk allows you to get extra milk from your breasts that can be given to your baby when you're not there.

Ask for help

All new mothers will need help in the beginning, so ask your friends and family to plan to help out. After the baby arrives, they can assist with meals, shopping, and the care of older children. This will allow you to spend plenty of time with your new baby.

Alternatives to Breastfeeding

Parents choose to feed their babies formula for a variety of reasons. You may even decide to breastfeed your baby while using an occasional bottle. It's important to explore all of the issues related to how you'll feed your baby.

• Even if you choose not to breastfeed exclusively, you can still use bottle-feeding time to bond with your baby.
• Make this your special time to feel close to your baby by talking, singing, holding, and making eye contact.
• Remember that it's not safe to prop bottles, so make sure that no one props your baby's bottle.
• Do not warm bottles in the microwave. Hot milk can burn your baby's mouth.

Types of formula

You can choose from 3 types of formula:

• Ready-to-feed. This is the most convenient because it's already prepared for you. This is also the most expensive.
• Liquid concentrate. All you do is add water.
• Powdered. This is the most economical, but also requires the most preparation time.

Your baby's pediatrician may recommend a specific brand of formula and tell you whether to sterilize or simply wash the bottles and nipples. Many women find that a dishwasher thoroughly cleans both if they are first scrubbed with a brush. Always check the expiration date and preparation instructions before you make your baby's formula. Follow the directions exactly.

Common Concerns and Discomforts

I am having problems with constipation.

Pregnancy hormones cause the digestive tract to relax and function more slowly, which can cause constipation. As your uterus enlarges, this can also cause constipation. What you can do:

• Drink plenty of fluids or add prune juice to your diet. Keep a bottle of water near you during the day.
• Increase your fiber intake (whole-grain foods, fresh fruits, and vegetables).
• Allow a regular time for bowel movements; this will often happen naturally after meals. Avoid straining since this can cause hemorrhoids.
• Please let us know if you think you need a laxative or stool softener.

I'm having problems with heartburn.

Heartburn (sometimes also called reflux) is caused by stomach acid coming up into your esophagus (the tube connecting your mouth to your stomach). Heartburn during pregnancy is caused by a hormone which relaxes the stomach sphincter that keeps the acid out of the esophagus. This same hormone causes a delay in stomach emptying so that more acid builds up. What you can do:

• Eat several small meals a day (about 6) instead of 3 large meals.
• Avoid spicy, fried, or rich foods.
• Avoid caffeine. This causes the stomach sphincter to relax even more.
• Do not lie down right after eating. Stay upright for at least 30 minutes.
• Keep the head of the bed higher than the foot of the bed.
• Try an antacid (like Tums or Maalox).

If your heartburn is still a problem, please let us know. There are prescription medications that you can use.

I lose my balance easily.

You've probably noticed how easy it is to get off balance and feel very clumsy. This is due partly to a pregnancy hormone called relaxin that softens the cartilage in your joints and pelvis. This is responsible for the pregnancy waddle that most women have when they walk. It's also a result of your center of gravity moving forward as your baby grows. Your baby should be fine even if you fall or bump yourself because a protective cushion of warm amniotic fluid protects the developing child. What you can do:

• Avoid wearing high heels.
• Don't participate in activities that require good balance.
• Use the handrail when walking up and down stairs.

If you fall, you should call Labor and Delivery right away to see if you should come in to be evaluated. 

I have difficulty sleeping.

As pregnancy progresses, leg cramps, breathlessness, contractions, the frequent need to urinate, and an active baby may all interfere with your sleep. You may need to try various options in order to find a comfortable position. What you can do:

• Use extra pillows to support your legs and back. Try sleeping on your side with pillows between your knees and behind your back.
• Have a light snack or a glass of milk before going to bed.
• Get regular exercise during the day to help you sleep more soundly at night.
• Practice relaxation exercises before going to sleep or if you wake up during the night.
• Take a warm (not hot) bath or shower before going to bed.
• Avoid caffeine, including chocolate, especially late in the day.
• Do not use sleeping pills or drink alcohol because they could harm your baby.

Lying on your side is better for you and the baby now that you are in your third trimester. When you are lying on your back, the weight of your uterus and your baby rests on the vena cava, the largest vein in your abdomen. When there is pressure on that vein, your blood pressure can go down and you may feel dizzy or light-headed.

• Sleep on your side with a pillow between your legs.
• If you find you have turned over onto your back, roll back onto your side.
• After week 16 of pregnancy, avoid exercises where you have to lie on your back for longer than 3 minutes.

I have leg cramps.

Leg cramps are common in mid to late pregnancy. They usually occur late at night and may wake you up. They may be caused by the pressure of your enlarged uterus on the nerves or blood vessels in your legs, from lack of calcium, or occasionally from too much phosphorus in your diet. What you can do to prevent leg cramps:

• Avoid too much phosphorus in your diet. This is found in highly processed foods, such as lunch meats, packaged foods, and carbonated beverages.
• If you're having frequent cramps (more than twice a week), increase the amount of calcium in your diet or take calcium supplements that don't contain phosphorus.
• Do leg stretches before bedtime.
• Wear leg warmers at night.
• Exercise moderately every day.
• Take a warm (not hot) bath before bedtime.

What you can do to relieve leg cramps:

• Sit on a firm bed or chair. Straighten your leg and flex your foot slowly toward the knee.
• Stand on a flat surface (a cold surface is preferable) and lift your toes up, as if to stand on your heels. Then try walking while keeping your toes up.
• Use a heating pad or hot water bottle to help with the muscle ache.
• Do not massage your calf during the cramp.

I have noticed changes in my skin.

As your baby grows, your pregnancy hormones can trigger changes in your skin. These changes should fade away after your pregnancy. These skin changes are not usually treated during pregnancy. If you're worried, talk to us about your concerns.

• Stretch marks. Your uterus is expanding beyond your belly button and your abdomen is stretching to fit it. This may cause reddish streaks on your abdomen. These stretch marks might also appear on your breasts, buttocks, or thighs. After birth, these will fade to fine silvery lines, which may or may not disappear. Oils, creams, or lotions will make your skin feel better, but they can't stop stretch marks from forming.
• Linea nigra. You may get a narrow, dark line that extends from your belly button to your pubic bone (the bone just above your vagina). This seems to occur more frequently with those who have dark hair and skin. It's caused by pregnancy hormones and will disappear or fade after birth.
• Chloasma. You may find brown patches on your nose, forehead, cheeks, and neck. This mask of pregnancy is called chloasma and also results from pregnancy hormones. The brown patches may darken in the sun, so use sunscreen. After birth, they should lighten and then disappear.
• Red spots. You may get red spots on your face, neck, upper chest, arms, or on the palms of your hands. These are tiny interconnected blood vessels that are caused by your pregnancy hormones. All redness should disappear after you give birth.

My baby's kicks are painful.

Your baby may settle into a position that is very uncomfortable for you. Your baby's kicks and twists can be strong and sometimes painful. When your baby drops into the pelvis (called lightening), the kicks will probably be less uncomfortable. If you are having your first baby, lightening can occur several weeks before delivery. For subsequent babies, it usually doesn’t happen until just before labor. What you can do:

• Change your position and hope your baby changes position too.
• Try taking a deep breath while you raise your arm over your head and then breathe out while you drop your arm.
• Try cupping your hands around your baby's buttocks and gently moving the baby.

There is pain and pressure in my pelvis.

Sharp, lower, midline pain is sometimes caused when a joint at the front of the pelvis (symphysis pubis) relaxes in response to pregnancy hormones. You may feel pelvic pressure or pain if your baby's head is low in the pelvis (after lightening occurs). You might have groin discomfort as the round ligaments that support the uterus continue to stretch. What you can do:

• Lie on your side to help relieve discomfort.
• Get up slowly from a sitting or lying down position. Slowly roll onto your side when getting up from a lying down position, and use your arms to get up. This helps prevent straining your round ligament and causing ligament pain.

I leak urine when I laugh or cough.

As your growing uterus puts pressure on your bladder, you might notice that you leak urine when you laugh or cough. This is common and is called stress incontinence. What you can do:

• Do Kegel exercises, which will strengthen your pelvic floor muscles and help reduce leaking. You can do these exercises any time: standing, sitting, waiting for a red light to change, or even while you're washing the dishes.
• Don't drink less fluid to keep urine from leaking because it won't help. You still need fluids to keep yourself and your baby healthy. Not drinking enough fluids may lead to preterm labor. Also, reducing fluids will not keep you from needing to get up at night to empty your bladder.
• Use a pad to keep your underwear dry.

If you leak enough to need a pad, you might have a leak in your amniotic sac, often called your bag of waters. Call us right away to discuss this.

My feet and ankles are swollen.

You may notice that your feet, ankles, hands, and fingers will become swollen, particularly at the end of the day. It's normal to have extra fluid in your tissues during pregnancy. What you can do:

• Get rest. Much of the swelling should disappear after a good night's sleep.
• Remove your rings if your fingers are puffy.
• Do not take diuretics (water pills) because they interfere with your normal fluid balance.
• Avoid high-sodium (salty) foods, such as potato chips.
• Drink 8 to 10 glasses of water each day.
• Keep your feet up on a stool or couch whenever possible.
• Avoid standing for long periods of time.
• Don't wear tight shoes or knee-high stockings.
• Wear support stockings and put them on before you get out of bed in the morning.
• Lie on your side to remove fluid from your puffy tissues.
• Sleep with your feet slightly higher than your heart. To do this, raise the foot of your bed by putting a thick blanket or pillows under the mattress.

I have varicose veins.

Varicose veins are visible, enlarged blood vessels in your legs. Your calves may ache or throb, even when the veins aren't visible. Most varicose veins will shrink or disappear after birth. What you can do:

• Don't stand for long periods of time.
• Avoid crossing your legs at the knees when sitting.
• Elevate your feet.
• Avoid tight clothing or stockings that hamper circulation.
• Wear support hose. This may help prevent aching calves.
• Exercise regularly. Try walking for at least 30 minutes each day on most days.

I have hemorrhoids.

Hemorrhoids (dilated, twisted blood vessels in and around the rectum) are common, especially in the last months of pregnancy when the uterus is pushing constantly on the rectal veins. Hemorrhoids can cause pain, itching, and bleeding during a bowel movement, but usually improve without treatment shortly after birth. What you can do:

• Keep your stools soft by increasing your intake of liquids, fruits, vegetables, and fiber.
• Avoid sitting for long periods of time. Lie on your side several times a day.
• Cleanse the area with soft, moist toilet paper, witch hazel pads, or Tucks pads.
• Apply ice packs to relieve discomfort.
• Take a sitz bath (a warm-water bath taken in the sitting position where only the hips and buttocks are covered) for 20 minutes, several times a day.
• Use Preparation H, Anusol, or 1 percent hydrocortisone cream to help relieve the pain.

I have lower back pain.

As your pregnancy progresses, your posture changes to accommodate your expanding uterus, and lower backaches often result. The pelvic joints loosen under the influence of hormones, so they are less supportive. Your lower spine curves more, which might strain your lower back muscles. What you can do:

• Squat when lifting heavy objects. Use your legs, rather than your back. Don't bend from the waist. Ask for help if you need it.
• Wear low-heeled, supportive shoes.
• Always roll to your side before sitting up from a lying position.
• Apply heat or cold to your back to help relieve the ache.
• Ask your partner for a nightly backrub.
• Use a firm sleeping surface. A rigid bed board under the mattress can help.
• Wear a maternity support belt.
• Light exercise like prenatal yoga and swimming can be helpful for your back.

I'm short of breath.

During pregnancy, you breathe more air in and out of your lungs. Sometimes you may feel as if you can't catch your breath. This feeling comes from your uterus pressing up on your diaphragm and crowding your lungs. Relief usually comes when your baby settles into the pelvis. What you can do:

• Sit up straight.
• Sleep with your shoulders propped up.
• Rest frequently.
• Drink more fluids. Keep water near you all day.
• Eat small, frequent meals.
• Avoid beverages that contain caffeine, such as coffee, tea, and soda.
• Wear clothes that fit loosely around the waist.

If you experience sudden, severe shortness of breath with rapid breathing, a rapid pulse, and chest pain, or if you have any blue color around your lips or fingernails, call 911 and get medical help immediately.

Preparing for Birth and Your New Baby

The third trimester is the time during pregnancy when we all look forward to the next exciting development: the amazing birth of your baby! There is so much to do to prepare for this arrival and we want this to be a healthy, safe, and beautiful experience for you and your family. The following information may be helpful in knowing what to expect:

• Signs of labor. As you get closer to your due date, the question of how you can tell if you're in labor becomes the most common concern for many women. Knowing the signs of labor and what to expect once it starts can help.
• Make a plan for birth. A birth plan is a document where you outline your wishes for your birth environment, any pain medication you would like to receive during childbirth, and your birth process. Your birth plan can be changed at any time. Creating a birth plan is a good way to communicate your wishes to the labor and delivery staff that will care for you.
• Possible complications. It's important to be aware of possible complications like preeclampsia, preterm birth or post-term pregnancy. Learning about these conditions is especially important since steps can be taken to prevent harm to yourself or your baby.
• Getting ready for your new baby. To prepare yourself for your new baby, consider choosing a pediatrician and taking steps to prepare your new baby's older siblings for his or her arrival.

Related Health Tools:

If you have an emergency medical condition, call 911 or go to the nearest hospital. An emergency medical condition is any of the following: (1) a medical condition that manifests itself by acute symptoms of sufficient severity (including severe pain) such that you could reasonably expect the absence of immediate medical attention to result in serious jeopardy to your health or body functions or organs; (2) active labor when there isn't enough time for safe transfer to a Plan hospital (or designated hospital) before delivery, or if transfer poses a threat to your (or your unborn child's) health and safety, or (3) a mental disorder that manifests itself by acute symptoms of sufficient severity such that either you are an immediate danger to yourself or others, or you are not immediately able to provide for, or use, food, shelter, or clothing, due to the mental disorder.

This information is not intended to diagnose health problems or to take the place of specific medical advice or care you receive from your physician or other health care professional. If you have persistent health problems, or if you have additional questions, please consult with your doctor. If you have questions or need more information about your medication, please speak to your pharmacist. Kaiser Permanente does not endorse the medications or products mentioned. Any trade names listed are for easy identification only.