Third trimester
of pregnancy
Fetal development

Height
~18 to 20 in
Weight
~7.5 to 9 lb
Highlights: Third Trimester
- 1Baby’s Development. In the final trimester, your baby gains about half their birth weight—around half a pound per week. By 28 weeks, eyes open and lashes are visible; by 30 weeks, lanugo sheds and scalp hair grows. Around 34 weeks, most babies turn head-down. At 39 weeks, your baby is considered full-term.
- 2Bodily Changes & Symptoms. Common symptoms include shortness of breath, frequent urination, heartburn, swelling in the feet or ankles, itchy skin, Braxton Hicks contractions, and sleep challenges. Sensitive gums and “looser” teeth may also occur. True labor contractions become regular and stronger, while Braxton Hicks ease with movement.
- 3Health & Wellness. Expect more frequent prenatal visits and a Group B strep test. Track your baby’s movements daily, and call your provider if movement decreases or if you notice concerning symptoms like headaches, swelling, vision changes, or heavy bleeding. Stay hydrated, eat a balanced diet, exercise moderately if approved, and rest often.
- 4Tips & To-Dos. This trimester is about preparation. Finalize your birth plan, preregister at your hospital or birth center, and plan your route there. Install the car seat, stock newborn supplies, and prepare freezer meals. Take childbirth or baby care classes, arrange childcare or pet care, and line up support for postpartum recovery.
Checklist for the third trimester
- 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 center. 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 labor 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 labor 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.
- 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 labor 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, labor and childbirth with little or no medical intervention—find out what comfort measures and labor 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 center.
- Plan, practice, and time the route you’ll take to the hospital or birth center.
- 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.
- Watch our free online childbirth education videos.
- 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.
- 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 center, 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 labor 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!

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You’ve reached the final stretch (literally! This is the most exciting and suspenseful trimester of pregnancy. You're bound to be impatient to meet your little one but hang in there—before long, you’ll have your newborn in your arms. Read on to learn all about what happens in the third trimester of pregnancy, including fetal development and common symptoms you may experience. We'll also provide a comprehensive to-do list starting three months before your baby’s arrival so that you’re as prepared as can be.
Highlights From the Third Trimester of Pregnancy
Third Trimester Weeks: When Does the Third Trimester Start and How Long Is It?
During pregnancy, it’s common to wonder, “When is the third trimester?” or “How many weeks 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 months the third trimester includes, it’s generally months 7, 8, and 9 of your pregnancy. When you reach the start of 39 weeks, your pregnancy is considered full-term. Some go into labor 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 labor, just in case your little one decides to make an early appearance. Read our article on full-term pregnancy for more on preterm, early-term, full-term, late-term, and post-term births.
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. For more on this, read our article about a baby’s average birth weight. 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 developed 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:
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:
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:
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 any of the following:
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
Two Months Out
One Month Out
FAQS AT A GLANCE
It’s common to wonder, “What week does the third trimester start?” The third trimester runs from 28 weeks until your baby is born. Your pregnancy is considered full term at the start of 39 weeks, and most babies are born in the two weeks on either side of their due dates.
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.
- American Academy of Pediatrics, Caring for Your Baby and Young Child: Birth to Age 5, 7th ed. (New York: Bantam Books, 2019).
- Cleveland Clinic. “Gingivitis.”
- March of Dimes. “Dental Health During Pregnancy.”
- March of Dimes. “Stress and Pregnancy.”
- Mayo Clinic. “3rd trimester pregnancy: What to expect.”
- Mayo Clinic. “Pregnancy weight gain: What's healthy?”
- Mayo Clinic. “Stages of Labor.”
- Mayo Clinic. “What causes ankle swelling during pregnancy—and what can I do about it?”



