Third Trimester of Pregnancy: 28-40 Weeks

You’ve made it! You’re in the final trimester! This is an exciting time when you start to ready yourself for the arrival of your little one. It won’t be long until they’re in your arms. Read our comprehensive guide to learn all about what happens in the third trimester of pregnancy, including fetal development, common third-trimester symptoms, and even a helpful to-do list to prepare yourself for your baby’s arrival.

Highlights From the Third Trimester of Pregnancy

Third Trimester Weeks: When Does the Third Trimester Start and How Many Weeks Is It?

During pregnancy, it’s common to wonder, “When is the third trimester?” or “How long is the third trimester?” Officially, the third trimester runs from 28 to 40 weeks of pregnancy, lasting about 13 weeks, but in reality, the third trimester ends when your baby is born.

So, how many months is the third trimester? Although there isn’t an exact answer, as it depends on when your baby actually arrives, the third trimester is considered about three months long. And if you’re wondering what month is the third trimester, it generally includes months 7, 8, and 9 of your pregnancy.

Your pregnancy is considered full-term when you reach the start of 39 weeks. Some go into labour a little earlier than this, and others give birth as late as 42 weeks. In fact, only a small percentage of babies are born exactly on their due dates, with most babies being born during the two weeks on either side of their estimated due date.

If a baby is born before 37 weeks, this is called a preterm birth. As you enter the third trimester, it’s important to know the signs of preterm labour, just in case your little one decides to make an early appearance.

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Your Baby’s Development in the Third Trimester

In the third trimester of pregnancy, your little one continues to grow at a fast pace. In fact, your baby will gain about half of their birth weight during the final months of your pregnancy.

By the time your baby is born, they may weigh between 5 1/2 and 9 1/2 pounds.

As your little one adds fat under their skin, they start to look like the baby you expect to see at birth. By 36 weeks, they’ll have done such a good job of growing that they won’t have much room to move throughout the rest of the pregnancy!

Keep reading for a few more fetal development milestones during the weeks of your third trimester.

28 Weeks: Eyes Wide Open

When you’re around 28 weeks pregnant, your little one can open and close their eyes, and they may have eyelashes.

30 Weeks: Shedding Hairs

During their second trimester, your baby develops a coat of fine hair called lanugo all over their body. At this point, they may start to shed this hair. But don’t be surprised if you notice a little leftover lanugo when your baby is born; some babies are born with patches on their shoulders, ears, and back.

Though only some babies are born with lanugo, most babies are born with a bit of vernix, a protective waxy coating, still covering their skin.

Around this week of pregnancy, your baby may also start to grow normal hair on their head.

31 Weeks: Controlling Body Temperature

Your baby’s brain is maturing and growing rapidly this week. Their brain can now control body temperature, so they no longer have to rely on the temperature of the amniotic fluid for temperature control.

Practicing skin-to-skin contact after your baby is born will also help your little one regulate their body temperature.

34 Weeks: Turning Head-Down

Around the time you’re 34 weeks pregnant, or soon after, your little one will most likely turn head-down in preparation for birth. They’re getting ready for their big journey! If your baby isn’t in a head-down position as you near the end of the third trimester—for example, if they’re in a breech position—your healthcare provider may recommend trying to turn your baby or may recommend a cesarean section.

39 Weeks: Full-Term Baby

By the time you reach the start of 39 weeks, your baby is considered full-term. Of course, they’ll continue to grow, and major organs like the lungs and brain will continue to develop in the years to come, but they’re ready for the outside world now.

Illustration of Fetal Development Week by Week

Check the illustrations below for a visual representation of how your little one develops week to week during the third trimester:

What’s in Store for You in the Third Trimester?

Here are some highlights to look forward to and things to keep in mind as you make your way through the third trimester:

• Having checkups and tests. Your healthcare provider will let you know about specific tests and checkups you may need during the third trimester. As an example, your provider will likely offer you a Group B strep test, a routine test that checks whether you carry the GBS bacteria. If the test result is positive, your provider can give you the appropriate course of treatment.

• Attending your baby shower. Take the time to enjoy this wonderful event and bask in the love your friends and family have for you and your little one. Afterward, be sure to send thank you notes for the gifts you received and, of course, to the party host.

• Nesting. As you approach your due date, you may have a strong urge to get your home ready for your baby. You might focus your energy on putting the finishing touches on your baby’s nursery, washing your baby’s clothes, installing the baby car seat, and doing some early baby-proofing. Some may also use this “nesting instinct” to clean, do home repairs, or cook batches of meals to freeze.

• Watching for signs of labour. Although you could go into labour anytime, it’s most likely to happen between 38 and 42 weeks. Look out for any signs of labour in the third trimester of pregnancy, such as lightening (the sensation that your baby has dropped lower), loss of the mucus plug, your water breaking, pain or cramping in your lower back or pelvic area, or contractions that get stronger and closer together. If you’re unsure if labour has begun, call your healthcare provider.

• Learning about labour and childbirth. Whether you plan to have a vaginal birth or a cesarean section, it’s a good idea to become familiar with all the possible eventualities. When it comes to labour, exploring topics such as what contractions feel like, labour inducement, and cervical effacement.

• Finalizing your baby name choice. Soon enough, the time will come when you’ll have your baby in your arms, and you’ll have to make that final baby name decision (including selecting a middle name if you want to give them one). If you’re still looking, check out our array of baby names—we've put together lists of names with various themes, including names from different countries and names beginning with each letter of the alphabet.

• Resting. It's wise to slow down and conserve your energy for labour, childbirth, and taking care of your newborn. If weather permits, take a leisurely walk outdoors a few times a week. The fresh air will invigorate you, get your blood circulating, and help you de-stress. Ask friends or family members to help you with any last-minute errands and treat yourself to a little me-time—you deserve it!

What Weeks and Months Are in the Third Trimester?

The image below indicates the weeks and months that are included in this trimester, as well as offering an idea of what your growing belly may look like:

Third Trimester Symptoms

These are some of the most common pregnancy symptoms during the third trimester:

• Shortness of breath. As your uterus gets larger, grows higher in your abdomen, and presses on your diaphragm in the 3rd trimester of pregnancy, you may experience shortness of breath. You might find that you can't make it up a flight of stairs without getting winded. The best strategy is to take it easy, move more slowly, and stand up or sit up straight so your lungs have more room to expand. If your breathing changes dramatically or if you have a cough or chest pain, contact your healthcare provider right away. The good news? Once your baby “drops” down into your pelvis in preparation for being born, breathing will become a little easier as the pressure is taken off your lungs.

• Frequent urination. When you enter the final weeks of your pregnancy, you may need to pee more often, given that as your baby moves further down into your pelvis, they may press on your bladder. You might also leak a little, especially when you laugh, sneeze, bend, or lift. If this bothers you, wear a panty liner. However, if you feel a gush or trickle of watery fluid, this could be your water breaking, a sign that labour is beginning.

• Heartburn. Just like the symptoms above, heartburn is common in the third trimester. The expanding uterus can push on your stomach and cause the acids to move upward, causing heartburn. Heartburn may also cause nausea in the third trimester, especially soon after eating.

• Swollen feet and ankles. Many notice a type of swelling, called edema, in their ankles and feet because of extra fluid retention, hormonal changes, and weight gain during pregnancy. If you notice this, it could help to elevate your legs whenever you can and soak your feet in cool water. To help you feel more comfortable, you may need to buy bigger shoes.

• Itchy skin. As your belly grows, you may start to experience itchiness as your skin stretches and dries out. Gently applying a moisturizing lotion and staying well-hydrated can help if you have itchy skin in the 3rd trimester of pregnancy.

• Sore gums and teeth feeling looser. Your gums may feel sensitive, and they may swell or bleed when you brush or floss. It might help to rinse with salt water and use a softer brush. Hormonal changes throughout pregnancy, including the third trimester, can cause your ligaments to relax (leading to round ligament pain), and these same hormones may also affect the tiny ligaments that hold your teeth in place. As a result, your teeth may feel looser. Experts say that it’s unlikely you’ll actually lose a tooth for this reason, and this feeling usually goes away after you’ve given birth. Keep flossing daily, brushing twice a day, and going to your regular dental checkups.

• Braxton Hicks contractions. In the third trimester, and sometimes even earlier, you may experience Braxton Hicks contractions. These “practice contractions” are useful for your body because they help your muscles prepare for labour. Braxton Hicks contractions may be mild to start with and feel like a tightening of your abdomen, but as your due date nears, they can become more painful. You may be wondering how to tell the difference between true labour contractions and Braxton Hicks. Essentially, Braxton Hicks come irregularly and often go away if you move or change positions; true labour contractions get more regular over time and don’t go away.

• Difficulty sleeping. It’s common to have trouble sleeping during the third trimester of pregnancy, especially if your bump is quite large and you can’t find a comfortable sleeping position. It’s also common to experience hot flashes at night in pregnancy, especially during the third trimester, thanks to those pregnancy hormones. If this is the case, try to make your bedroom a place of relaxation and comfort with these helpful sleeping tips for pregnancy.

Precautions to Take in the Third Trimester of Pregnancy

The third trimester of pregnancy, from week 28 until birth, is a time of rapid growth for your baby and exciting physical changes for you. As your body prepares for birth, you may be wondering what you should be doing and what not to do in your third trimester of pregnancy. Here's what to keep in mind and steps you can take to help safeguard your health and the health of your baby:

• Track fetal movements. If your healthcare provider asks you to track your baby’s movements, follow your provider’s guidance on how to count your baby’s kicks. If you notice a decrease in your baby’s activity during pregnancy, contact your healthcare provider.

• Maintain a healthy diet: Continue eating a balanced diet rich in fruits, vegetables, whole grains, lean protein, and dairy products. Avoid foods that potentially contain harmful bacteria, such as raw or undercooked seafood, undercooked meat or eggs, and unpasteurized dairy products.

• Stay hydrated. Drink plenty of fluids throughout the day, especially water. Dehydration can lead to complications such as preterm labour.

• Avoid heavy lifting. Heavy lifting can put undue strain on your back and could potentially cause harm to your baby. If you must lift something, bend at your knees and keep the object close to your body.

• Exercise regularly. Continue engaging in regular physical activity, as advised by your healthcare provider. Exercise during pregnancy can help alleviate common pregnancy complaints such as backaches and fatigue. If you’re running during pregnancy, follow your healthcare provider's recommendations and stick to safe practices.

• Monitor your weight. Throughout your pregnancy, it’s important to maintain a healthy weight, which will vary from person to person. Your healthcare provider can help you stay on track and let you know how much weight gain is OK for you in the third trimester. You can also try our pregnancy weight gain calculator.

• Listen to your body. Rest when you're tired and take breaks throughout the day. If something doesn't feel right, contact your healthcare provider.

• Prepare for childbirth. Educate yourself on the signs of labour and what to expect during childbirth. It’s extremely helpful to know the reasons that mean it’s time to go to the hospital while pregnant in the third trimester. You can find more information on this in our section “What’s in Store for You in the Third Trimester.” Attend prenatal classes, if possible, and plan your route to the hospital or birthing centre.

Remember, these precautions are general guidelines and may not apply to every pregnancy. Always rely on your healthcare provider for personalized guidance during your third trimester.

When to Contact Your Healthcare Provider

During the last trimester of your pregnancy, maintaining communication with your healthcare provider is essential. While it's normal to experience a variety of symptoms as your body prepares for childbirth in the third trimester of pregnancy, you'll want to contact your healthcare provider if you notice

• a sudden decrease in movement or it takes longer than two hours to feel 10 movements when counting fetal movements

• signs of preterm or full-term labour, such as regular or frequent contractions; a constant low, dull backache or cramping; a sudden gush of clear, watery fluid from your vagina; or a feeling of pressure in the pelvis

• heavy vaginal bleeding

• a severe headache, swelling, or sudden blurry vision

• a fever above 100.4 degrees Fahrenheit

• persistent nausea or vomiting.

Always remember, it's better to err on the side of caution when it comes to your health and the health of your baby. If you feel that something is not quite right or if you have any concerns, don't hesitate to reach out to your healthcare provider.

3rd Trimester Checklist

In the third trimester, take advantage of your excitement and focus your energy on getting your pre-birth tasks done. Just remember to rest often and don’t overdo it!

Three Months Out

• Take a deep dive into what’s to come in the third trimester by reading our week-by-week pregnancy articles.

• Ask your healthcare provider about any vaccinations you need to get this trimester, including the Tdap vaccination (which helps protect your baby against whooping cough, diphtheria, and tetanus) and the annual flu and COVID-19 shots.

• Ask your healthcare provider whether you’re at a high risk of preeclampsia—a high blood pressure disorder—and what signs to look out for.

• Ask your provider how long you can safely continue working.

• Look for a healthcare provider for your baby, such as a pediatrician or family physician.

• Take a childbirth class with your partner. You’ll probably learn things like comfort measures, relaxation techniques, and stretching exercises. These classes will also help your partner learn about their important role. Your healthcare provider will be able to recommend a good class near you.

• Pre-register at the hospital or birth centre. If you’re unsure how to do this, ask your healthcare provider.

• Purchase and install your baby car seat so it’s ready for the drive home from the hospital and beyond.

• Stock up on household staples and supplies so you don’t have to do any major shopping just before labour or in those first few weeks with your baby.

• If you’d like to have a birth plan, discuss your options and preferences with your healthcare provider regarding labour and delivery.

• Gather some recommendations for childcare and babysitters so you’re ready once your baby arrives.

• Choose or start designing your birth announcement. Ideally, get it far enough along so that all you have left to do is fill out the date of birth and name and add a picture.

• If you have older children, start preparing them for the arrival of their baby sibling.

• Consider whether you’d like to do cord blood banking and discuss your preference with your healthcare provider.

Two Months Out

• Keep going to all your prenatal appointments, so your healthcare provider can follow your baby’s progress and monitor your health as you approach your due date.

• Find out what your options are for pain management during labour and childbirth. One option, as an example, is to have an epidural, but there are also non-medical options as well. Discuss your preferences with your provider and birth partner. If you’re planning a natural delivery—in other words, labour and childbirth with little or no medical intervention—find out what comfort measures and labour positions you could try as well as any equipment or facilities the hospital may have available, such as a birthing ball or pool.

• If it’s possible, tour your hospital or birth centre.

• Plan, practice, and time the route you’ll take to the hospital or birth centre.

• Think about who you want to be present at the birth and discuss your birth preferences with your birth partner. Go over things like who will cut the umbilical cord.

• Have your hospital bag packed and ready to go just in case your little one makes an unexpected early appearance. Make a list of anything you can only add at the last minute (like your phone and charger) and have that on top of the bag as a reminder.

• Take another class—for example, try one about baby care, infant CPR, or breastfeeding.

• If you’re considering breastfeeding and would potentially like the help of a lactation consultant, start researching your options now.

• Finish planning and decorating your baby’s nursery.

• Start writing thank you notes for baby shower gifts you’ve received.

• Make sure you have all the essentials for your baby, like a crib, car seat, clothes, and diapers.

• Depending on the type of work you do, you might like to start getting organized to ensure that your co-workers know what might need to be done while you’re away. Speak to your employer about any leave paperwork that still needs to be done.

One Month Out

• Ask your healthcare provider whether you’ll have additional checkups as you near your due date and when these will be scheduled.

• Ask your healthcare provider if it’s OK to have a photographer or videographer there for the birth of your baby if this is your preference. Then check with the hospital or birth centre, as some facilities may not permit recording or filming. Organize a photo shoot if you’d like to have one after your baby’s birth.

• Consider putting a waterproof cover on your mattress, just in case your water breaks during the night.

• Wash everything your baby will wear and organize clothes by size so you can find what you need more easily.

• Stock up on diapers and wipes like Pampers Swaddlers and Sensitive Wipes. It’s a good idea to have a variety of diaper sizes (such as sizes N, 1, and 2) so you’re equipped for when your baby arrives, no matter how big they are.

• Wipe down and sanitize anything else your baby may come in contact with, like the car seat, crib, and baby bottles.

• Prepare some meals and stock your freezer.

• If friends or family have offered to lend a hand now or after you give birth, go ahead and take advantage of their help. Whether they’ve offered to help with minding your older children or doing grocery shopping, it can all make this busy period a bit easier.

• Think about and organize who will care for your older children (and pets if you have them) during your labour and hospital stay.

• Read up on the postpartum recovery period so that you know what kinds of things to expect in the weeks and months after your baby’s birth.

• Sign up for the Pampers Club app to get rewards for all the diapers and wipes you'll be purchasing.

• Now, there’s just one last box to check: slow down and make fewer demands on yourself. It could be a long time before you get another chance to relax like this!

The Bottom Line

The third trimester is a pivotal period in pregnancy, a time of significant growth for your baby and profound physical and emotional changes for you. Understanding what to expect in the third trimester and how to care for yourself during this time can help you navigate these final weeks of pregnancy with confidence and assurance. Remember, open communication with your healthcare provider and responding promptly to any concerns can greatly contribute to a healthy pregnancy and the safe arrival of your baby. The incredible journey of parenthood is just around the corner!

_{How We Wrote This Article The information in this article is based on expert advice found in trusted medical and government sources, such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.}