Healthy Pregnancy: Your Third Trimester Pregnancy Guide

Learn about your baby’s development, as well as any aches, pains or conditions you may experience during the third trimester.

Medically reviewed in August 2019

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You’re in the home stretch of pregnancy, but your baby—and your body—still have plenty of growing to do. We talked to OBGYN Mindy Luck, MD, of Medical City Arlington in Texas to get the facts on the third trimester, including how your body is preparing for the big (labor) day. Click through to learn what you can expect during these last few weeks of pregnancy.

Your First Trimester Guide
Your Second Trimester Guide

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28 Weeks – Baby’s Size: Large Eggplant

Your baby: He can blink and has eyelashes. He can even see light that shines on your tummy.

You: You’ll want to visit your OBGYN every two weeks. And, your doctor can probably tell if your baby is positioned head- or feet-first. Don’t worry if your baby is breech (bottom down) right now, he’ll probably change positions in the next couple of months.

What the doc says: That burst of energy you experienced in the second trimester may be long gone now that you’re in the third trimester. “You’re getting bigger and [probably] uncomfortable,” says Dr. Luck. Hang in there!

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29 Weeks – Baby’s Size: Butternut Squash

Your baby: She’s just over 15 inches long and is growing quickly. Make sure you’re eating plenty of healthy foods rich in protein, calcium, folic acid and vitamins to help keep her energized and active inside your belly.

You: You may experience constipation, heartburn and hemorrhoids this trimester. Eat lots of fiber-rich foods to get your bowels moving and avoid spicy and greasy foods to reduce your risk of heartburn.

What the doc says: It’s time to sign up for a birthing class, says Luck. Make sure you start no later than 34 to 36 weeks, so that you complete all the classes before your baby arrives.

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Week 30 – Baby’s Size: Large Cabbage

Your baby: He’s practicing breathing and may even hiccup, which will feel like tiny flutters of movement.

You: Don’t be surprised if you go up a shoe size. Your ligaments may have softened thanks to hormone changes, causing your feet to spread permanently.

What the doc says: You’ll gain most of your weight during the third trimester. “It’s typical to gain about a pound a week during these last 12 weeks,” Luck says.

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Week 31 – Baby’s Size: Coconut

Your baby: Your baby is growing rapidly. She’s moving a lot more these days, too. Her head can turn from side to side and you’re probably feeling lots of wiggles and kicks.

You: Colostrum, or premilk, may leak from your breasts. If it doesn’t, it’s nothing to worry about. Your body is making it even if you don’t see it.

What the doc says: Hopefully you’ve been counting kicks. “Babies that are healthy and happy are active, and babies that are sick don’t move very much or at all,” explains Luck. Count kicks a couple hours after dinner and if it’s fewer than 10 kicks over the course of two hours, call your doctor, she says. Note that the position of your baby or placenta may affect your ability to feel movement; check with your provider, either way.

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Week 32 – Baby’s Size: Napa Cabbage

Your baby: Your baby will gain up to half of his birth weight during these last two months. He has toenails, fingernails, eyebrows and maybe even a full head of hair by now.

You: Feeling lightheaded or dizzy? Low blood sugar may be the culprit. Keep snacks high in carbs and protein with you during the day to eat when you feel lightheaded.

What the doc says: You’ll definitely feel more back, hip and pelvic pain and pressure these days, says Luck. You may feel like you have to go to the bathroom all of the time, too, she adds.

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Week 33 – Baby’s Size: Pineapple

Your baby: She can see, feel and hear things now. Her lungs are almost fully developed, and her wrinkly skin is smoothing out.

You: Your walk may have turned into a waddle, and it may feel impossible to find a comfortable position to relax.

What the doc says: Low back pain that is persistent is probably normal pregnancy back pain. But if you experience back pain that comes and goes in a regular pattern, you may be in labor, Luck warns. Tell your doctor about these symptoms.

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Week 34 – Baby’s Size: Cantaloupe

Your baby: His cheeks and legs are getting chunky. His new fat layers he is gaining will help him control his body temperature after he is born.

You: You’re probably feeling more sluggish these days, but it shouldn’t be as intense as it was in the first trimester. You may also notice stretch marks and extra body hair.

What the doc says: You may feel false contractions—typically a few in the morning and a few at night. “Let your doctor know if the contractions are closer than every 15 minutes or if they are consistent for more than an hour,” Luck says.

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Week 35 – Baby’s Size: Honeydew Melon

Your baby: She’s about 5.5 pounds and taking up lots of space in the womb. While there’s not much room for her to wiggle, you should still feel her kicking.

You: From this point on, you’ll want to visit your doctor every week.

What the doc says: Expect to take lots of bathroom breaks during these final weeks of pregnancy, as baby gets bigger and puts pressure on your bladder, says Luck.

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Week 36 – Baby’s Size: Canary Melon

Your baby: Your baby will shed and swallow the skin-coating vernix caseosa and the downy covering of hair on his body. These two substances will be in his first poop after he is born.

You: Your baby may drop down to your pelvis around this week, especially if it’s your first baby. When this happens, it should ease heartburn symptoms and make it easier for you to breathe.

What the doc says: The doctor will check for Group Beta Strep (GBS) in your vagina and to see if your baby is positioned head down or breech. If the baby is breech, your doctor will determine whether or not he can be repositioned. If he cannot be moved, your doctor will schedule a C-section, says Luck.

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Week 37 – Baby’s Size: Winter Melon

Your baby: Her lungs should be fully functional now. She also has developed a sleeping and waking routine as she prepares for life outside the womb.

You: You may notice an increase in vaginal discharge in the last weeks of your pregnancy. If you see a heavier discharge tinged with a small amount of blood or mucous, labor is probably only a few days away.

What the doc says: “Contractions for labor can vary, but occur every three to five minutes from the beginning of one to the next,” Luck says. If they last for one minute and come every five minutes for an hour, and/or increase in intensity, it’s time to go to the hospital, she adds.

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Week 38 – Baby’s Size: The Length of Rhubarb

Your baby: His organs should be fully developed and ready for life outside the womb.

You: It’s normal to experience some swelling in your feet or ankles towards the end of pregnancy. But, if you develop swelling in your hands and face and have a headache that doesn’t respond to medicine, you should call your doctor immediately, as you may have preeclampsia.

What the doc says: “Preeclampsia is a disease only of pregnancy and the only cure is delivery,” Luck says. It may cause hypertension, kidney problems and seizures. Any unusual symptoms should be reported to your doctor—especially a headache or swelling in the hands and face.

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Week 39 – Baby’s Size: Mini-Watermelon

Your baby: Your baby is considered full term! It’s quite possible your little one will make his debut this week.

You: You may experience more noticeable Braxton-Hicks contractions as your uterus practices labor. If you feel more consistent contractions or if your water breaks, you’re in labor.

What the doc says: “Water breaking is different for every person,” Luck explains. “Some women may feel or hear a pop, and others may feel just a trickle that keeps coming.” If you have a discharge that is enough to soak multiple sanitary napkins, call your doctor, she says.

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Week 40 – Baby’s Size: Small Pumpkin

Your baby: His skull bones are separated so that he can fit through the birth canal during labor. Don’t be alarmed if he comes out with a cone-shaped head. It’ll go away after a few hours or days.

You: Congratulations on making it to your due date! If you don’t go into labor within a week, your doctor may recommend giving you a non-stress test to check on the baby.

What the doc says: “It’s really common for women to go past 40 weeks,” says Luck. But, don’t worry. Your doctor won’t let you go past 42 weeks and will probably talk to you about induction between weeks 41 and 42.

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