Third Trimester of Pregnancy

You’re done with the second trimester! While you’re this much closer to meeting your new baby, the third trimester can feel like the longest for a lot of reasons. We promise you won’t be pregnant forever (even if it seems that way), so try your best to power through these final weeks.

Some of the early pregnancy symptoms you thought were over, like fatigue and frequent peeing, will return this trimester. In addition, you’ll start to have new symptoms, like Braxton-Hicks contractions, hemorrhoids and annoying aches and pains. You might find yourself feeling anxious, too, as you get closer to baby’s due date. It’s time to take extra good care of yourself—take naps, meditate, whatever relaxes you.

Your baby is really busy during the third trimester, putting all the finishing touches on their development as they get ready to enter the world. They’ll be packing on the pounds—it starts to get cramped in there—and brain and neuron development go crazy during these weeks.

Here’s what to expect during your third trimester of pregnancy.

How long is the third trimester?

The third trimester of pregnancy lasts from week 28 through birth, whether that’s on your due date, before or after. A 2013 study found that only five percent of babies are born on their due date, so chances are pretty high that your third trimester will either be shorter or longer than estimated (you could go as long as 42 weeks!). This is especially true if you’re carrying multiples, as they are usually born earlier.

Baby’s development in the third trimester

At 28 weeks, the start of your third trimester, baby is around 9.7 inches (about the size of a Blockbuster VHS tape). By the end of your third trimester—when you’ll meet your baby!—they’ll be about 14 inches from crown to rump and weigh anywhere from six to nine pounds, though they’re likely to be smaller if they’re born before 37 weeks.

After 30 weeks, your baby will start putting on around a half a pound a week until birth. It will get cramped in the amniotic sac, and as space gets tighter, your baby will start to nestle into the fetal position.

Around 36 weeks (though it could happen earlier or later), baby will begin to shift their position down away from your ribcage and toward your pelvis as they get ready for birth. It’s known as dropping or lightening, and it’s one of the early stages of labor (but don’t get your hopes up; labor may still be several weeks away after baby drops). You’ll likely find it easier to breathe after baby has moved down, and heartburn may be less frequent, but the urge to pee, hemorrhoids and a lovely new symptom known as “lightning crotch” will likely get worse.

During the third trimester, your baby’s brain and neuron development is in full effect. The brain continues to develop the important neural connections for the five senses so your baby can get ready to see, feel, touch, taste and hear when they’re born. They even start dreaming—rapid eye movement has been detected!

Your little one’s bones are hardening, but your baby’s skull will still be soft at birth to allow the head to move more easily through the birth canal (which is good, because that’s your vagina). These soft spots between parts of their skull are called fontanelles, which you may notice as slight dips in their scalp once they’re born, and it can take a couple of years for them to close.

By 32 weeks, most of baby’s major internal organs are well developed, though their brain and lungs will continue to develop into childhood and beyond. Since almost all internal systems are ready to go, a baby that is born prematurely at 32 weeks or later has a 95% chance of survival.

At 39 weeks, your baby is considered full term. You may have heard in the past that fetuses are considered “at term” at 37 weeks, but studies have shown that there is quite a bit of difference in babies born at 37 weeks versus 39 weeks, so the stages of “term” babies are now set as early term (37-38 weeks), full term (39-40 weeks), late term (41 weeks) and post term (42 weeks).

Third trimester pregnancy symptoms

Braxton Hicks contractions

During your third trimester, you may begin to experience Braxton Hicks contractions as your body prepares for labor. During these “false” contractions, your uterine muscles tighten for anywhere between 30 seconds to two minutes. But the way they feel can differ from person to person, says Al Bradlea, Dona-certified doula and lactation consultant. You might feel a little discomfort in your abdomen, you might see your belly muscles tighten near your belly button or you might not notice anything at all.

How can you tell the difference between Braxton Hicks contractions and ones that are the real deal? Labor contractions don’t ease up if you change positions or get up or move around, and they increase in both intensity and frequency with time. Use these Braxton Hicks contractions as a chance to practice those breathing methods you’ll learn in your childbirth classes, if you take them.

If you determine that it’s Braxton Hicks contractions you’re feeling, don’t get your hopes up for labor. “It can be infuriating because Braxton Hicks don’t necessarily mean labor is right around the corner,” says Bradlea. “They can last for weeks before giving birth.”

Breast changes in the third trimester

Along with your belly, your breasts are probably getting bigger every day. By the end of your pregnancy, your breasts may have grown by as much as two cup sizes! Your nipples and areolas may become darker and more pronounced, with tiny bumps around them. These are known as Montgomery’s tubercles, and they secrete an oil to keep your nipple area lubricated while breastfeeding.

Closer to your due date, your nipples may begin leaking a yellowish fluid. That’s colostrum, and, if you’re breastfeeding, it’s the immunity-rich milk your baby will eat in the first few days after they’re born.

If you’re planning on breastfeeding after your baby is born, the third trimester is a good time to take a breastfeeding class. If you’ll be going to back to work or think you’ll want to pump in order for others to give baby a bottle, research which breast pump you might want. You may be able to get a free breast pump through your insurance. Other supplies that can be helpful on your breastfeeding journey are nursing bras, nipple creams, nursing pillows and nursing tops.

Discharge and spotting

It’s very common to have more white-colored vaginal discharge during the third trimester because of your increased estrogen levels. (If there are some streaks of blood and the discharge is particularly gelatinous, it may be your mucus plug coming out, which is an early sign of labor. If so, call your midwife or OB.)

A little spotting in the third trimester is normal, especially after sex, as your cervix is easily irritated. But if you see a lot of blood, call your doctor since it could indicate something is wrong with your placenta.

Lower back, hip and pelvic pain

Your lower back and pelvis are under a lot of tension right now, thanks to all that extra weight and the increased hormones preparing your body for labor. So it’s no surprise that you may be feeling some pain in your lower back and hips as things loosen and your center of gravity shifts, especially if you’ve changed your posture to accommodate your growing belly. Try wearing a supportive belly band to help keep the strain off your hips and lower back.

Pain further down, however, is likely due to strain on the muscles at the base of your pelvis. “Tense pelvic floor muscles can contribute to painful sex, tailbone pain, vaginal pain, rectal pain, incomplete bladder emptying, incomplete bowel movements or constipation,” Dr. Sara Reardon, board-certified pelvic floor physical therapist and the voice behind @the.vagina.whisperer, tells Babylist. Regular exercise like walking, swimming and stretching can help. A pelvic floor physical therapist can also massage the appropriate muscles to help relieve the pain and give you guidance for relaxing your tense pelvic muscles.

Sciatica

If you’re feeling tingling, numbness or shooting pain through your lower back, butt and thighs, you probably have sciatica. This is when your uterus puts pressure on your sciatic nerves. Stretching, changing positions often, taking a warm bath or applying compress can help soothe your pain.

Shortness of breath

As your uterus gets bigger, it presses against your rib cage and diaphragm, making it harder to breathe. Try standing up straight to allow more “breathing” room for your lungs, and if it affects your sleep, prop yourself up with some extra pillows. You can also practice some labor breathing techniques. If it becomes difficult to catch your breath at any point, it’s time to slow down and take a rest, and call your doctor if resting doesn’t improve your breathing. Toward the end of your pregnancy, your baby will drop, allowing you to breathe easier.

Mild swelling

It’s very common to have swollen ankles or feet in the later weeks of pregnancy, and it happens for several reasons: “During pregnancy, your blood volume increases 50 percent—and all that extra blood causes swelling,” says Erica Chidi, doula, health educator and advisor for Perelel Health. “Plus, your growing uterus can interrupt the flow of blood, making fluid build up in your legs. Hormonal changes also make your body hold on to more water.”

You can reduce the swelling by wearing compression socks, applying cold compresses, reducing your sodium intake and generally staying off your feet as much as possible. However, if you experience sudden swelling in the hands or face, call your doctor, as it could be a sign of preeclampsia.

Lightning crotch

Not everyone experiences lightning crotch, but if you do, you’ll understand that it was named appropriately. It’s a quick, sharp pain in your pelvis, vagina or rectum, particularly when you or baby move. The pain is caused by baby pressing on specific nerves, and it gets worse once baby drops further into your pelvis. Thankfully it goes away as soon as baby is born.

Hemorrhoids

Sorry to say, but hemorrhoids during pregnancy are pretty common. In the third trimester, they’re most often caused by constipation (which is caused by pregnancy hormones) and increased pressure on your pelvic area. Just like non-pregnancy-related hemorrhoids, they typically come with itching, “pain or fullness around the anus, pain with bowel movements, or the feeling of needing to have a bowel movement,” says Dr. Stephanie LaFave.

Thankfully, there are a lot of relief options available. “There are lots of simple over the counter things people can do to get relief, like herbal sitz baths, witch hazel pads, or applying a baking soda paste to quell itching,” Texas-based doula Carrie Murphy says. Keep these remedies in mind, as hemorrhoids are common after childbirth, as well.

While these aches and pains are normal, if you’re experiencing severe cramping or abdominal pain, vomiting (in the second or third trimesters), painful or burning urination, bleeding or a high fever, be sure to call your doctor. Don’t wait until your next prenatal appointment.

Sleep and the third trimester

You’ll probably begin to slow down again after that energy burst from your second trimester. Fatigue sets in again during your third trimester thanks to the extra weight, aches and pains, not to mention sleep can be more difficult now. “The growing fetus, especially in the third trimester, can push against internal organs, including the lungs, and make it difficult to not only breathe but get comfortable, which, if it happens overnight, can ultimately impact sleep,” says Dr. Nilong Vyas, sleep pediatrician with Sleepless in NOLA Sleep Consulting and medical reviewer for SleepFoundation.org.

A pregnancy pillow can help you get comfy at night by supporting your bump, hips and knees. “I encourage [pregnant people] to use as many props as needed to become comfortable in the bed, including pillows, positioners, and cooling blankets,” Vyas says. Creating a dark, cool, quiet sleep space can also help you fall or stay asleep.

You may also experience insomnia thanks to an increase in anxiety as your due date approaches. If you’re having trouble falling asleep, try some pregnancy meditations. And know you’re not alone—an estimated 75% of pregnant people suffer from insomnia during the third trimester.

Provider appointments during the third trimester

During the third trimester, your prenatal appointments become more frequent—every two weeks from 28 to 35 weeks, and then weekly until you deliver.

Cervical checks

Around week 38, your provider will probably do a cervical exam to see if you are starting to dilate (the opening of the cervix, which is measured in centimeters) or efface (the thinning of the cervix, which is measured in percentage). For a successful vaginal birth, your cervix will be 10 centimeters and 100% effaced.

Group B Strep test

Between 35 and 37 weeks, you will be screened for Group B strep, usually with a vaginal swab. This common bacteria is found in 25% of pregnant people who may or may not experience any symptoms. If you are positive for Group B strep, try not to worry—treatment is easy. “The standard treatment when GBS is found in the vaginal-anal area is prophylactic antibiotics given through an IV during labor or after the bag of waters is open,” says Evaly Long, licensed midwife with Hummingbird Midwifery. “Typically this antibiotic is Penicillin unless one has an allergy.” If you are planning a home birth, check with your midwife about being able to have IV antibiotics at home.

Checking baby’s position

Around week 35, your provider also will probably check to see if the baby is head-down (cephalic, with their head toward the birth canal) or head-up (breech, with their feet toward the birth canal). The safest way for a baby to be delivered vaginally is in the head-down position, so your doctor may recommend some approaches to “turning” the baby if they’re still head-up in the last few weeks.

Kick counts

By the third trimester, you’re probably used to feeling baby’s turns, kicks and jabs. In order to monitor baby’s movement, your provider may want you to do kick counts.

Sit or lay down in a quiet room and pay extra attention to what baby is up to. Look for 10 distinct movements in a two-hour period. Most of the time, you’ll feel them within five minutes, but sometimes it can take longer.

Try to do the kick counts at the same time every day (when baby is usually most active) and note how long it takes to get all 10. If you notice anything different about your baby’s pattern—or don’t feel any movement at all—trust your gut and call your doctor.

Weight gain in the third trimester

During the third trimester, the average pregnant person will gain between 1/2 pound and 1 pound per week. That means by the end of a full-term pregnancy, someone with a mid-range BMI (18.5-24.9) will have gained between 25 and 35 pounds.

Your provider should be tracking your weight throughout your pregnancy to ensure you’re gaining the appropriate amount of weight for your pre-pregnancy BMI, but if you’re curious what range you may be aiming for, there are weight recommendations for both single pregnancies and twin pregnancies.

Using a pre-pregnancy BMI range of 18.5-24.9 and a full-term newborn weight of seven pounds (the average in the US), here’s how that weight gain typically breaks down:

7.5 lbs	Baby
1.5 lbs	Placenta
2-3 lbs	Increased Fluids
2 lbs	Increased Uterus
1-3 lbs	Increased Breast Tissue
3-4 lbs	Increased Blood Volume
6-8 lbs	Maternal fat, protein and other nutrients
2 lbs	Amniotic Fluid

Sources:

• Al Bradlea, Dona-certified doula and lactation consultant
• Dr. Robyn Horsager-Boehrer, ob-gyn: 5 ways to manage swollen legs and feet during pregnancy
• Erica Chidi, doula, health educator and CEO of LOOM
• Dr. Stephanie LaFave, MD
• Carrie Murphy, certified full-service doula
• Dr. Nilong Vyas, MD, board-certified pediatrician
• Evaly Long, licensed midwife