Now that you're 31 weeks pregnant, your baby's brain is getting more sophisticated and he's more active than ever in there — pedaling his feet, sucking his thumb and practicing other important skills for the real world.

You may be running to the bathroom more frequently and feeling tired faster these days.

Your Baby at Week 31

At a Glance

Brain connections
Brain connections
Your baby's brain connections are developing at a rapid pace, which is a good thing since he has to make billions of them!
Sleepy baby
Sleepy baby
Your baby is a drowsy one, putting in longer stretches of snooze time, specifically REM sleep. Want to wake him up? Eat or drink something sugary.
Such a smarty
Such a smarty
Your brainy baby can already process information and pick up signals from all five senses.

31 weeks pregnant is how many months?

If you're 31 weeks pregnant, you're in month 7 of your pregnancy. Only 2 months left to go! Still have questions? Here's some more information on how weeks, months and trimesters are broken down in pregnancy.

How big is my baby at 31 weeks?

Weighing in at 3-plus pounds and measuring about 16 inches long, your baby is quickly approaching his birth length — though he's got to pack on another 3 to 5 pounds before delivery day.

Baby is sleeping more

He's putting in longer stretches of sleep, which is why you're probably noticing more defined patterns of wakefulness, movement and rest.

Baby's developing five senses

Your baby's brain is working overtime these days, developing faster than ever. Connections between individual nerve cells — he's got to make billions of them! — are being made at a super fast rate. He's now processing information, tracking light and perceiving signals from all five senses.

Sure, your baby may not be able to smell too much right now, though he likely can smell and taste different foods you eat through the amniotic fluid as well as catch a whiff of some beauty products you use (which also wind up in the amniotic fluid).

Lucky for you and your baby, yours will be one of the very first scents he breathes in, a scent that will quickly become his very favorite.

Pedaling his feet and sucking his thumb

So what's your little dove doing all day while you're busy feathering your nest for his arrival? Making faces, hiccupping, swallowing, breathing, pedaling with little hands and feet along your uterine wall, and even sucking his thumb. In fact, some babies suck their thumbs so vigorously while in the womb that they're born with a little blister on their thumbs!

Your Body at Week 31

31 Weeks Pregnant

Shortness of breath

So your stomach feels like it's in your chest and your lungs feel like... Hmmm... They don't even feel like they're there anymore, do they?

Movin' on up at 31 weeks pregnant, your uterus can now be felt about 4 inches above your belly button. This means that your uterus is pushing all the internal organs that used to be there somewhere else, crowding your diaphragm and lungs and making it more difficult for them to expand fully.

The result: Your body is spare on air and will be until your baby drops near the end of pregnancy in preparation for birth. While this shortness of breath may feel very uncomfortable to you, your baby is as happy as a clam because he’s getting his oxygen from the placenta.

That out-of-breath feeling may get better toward the end of your pregnancy, when your baby drops down into your pelvis in preparation for delivery. Until then, be sure to stand as straight as you can given the weight you're carrying around, eat smaller, evenly-spaced meals and sleep propped up on your left side so that your lungs have more space to... well, breathe.

How a baby responds to sex

Sex and orgasm can have an interesting effect on babies in the womb, as you may have noticed. Some are very quiet when their parents have sex — rocked to sleep by the rhythmic movement, perhaps — while others become active themselves.

Both responses are completely normal and in no way indicate that your baby is aware of what's going on.

So keep enjoying your sex life as much as you like and for as long as you can — which, with your practitioner's approval and a few advanced Twister-type moves, can be right up until delivery day. Pretty soon, jumping into bed together with a baby in the house won't be quite so easy or convenient.

Pregnancy Symptoms Week 31

More frequent urination
More frequent urination
Backaches
Backaches
Clumsiness
Clumsiness
Pregnancy brain
Pregnancy brain
Sleep problems
Sleep problems
Occasional headaches
Occasional headaches

Tips for You This Week

Skip the bumpers

Setting up the crib? Don’t buy or register for bumpers. Cute as they may look, bumpers pose a serious sudden infant death syndrome (SIDS) risk — so much so that in May 2022, crib bumpers were officially banned

Other cute-but-unsafe bedding to skip: pillows, stuffed animals and blankets.

Pack your hospital bag

Delivery day is getting close, so it's time to pack your hospital bag if you haven't already.

Along with necessities, you may want to stash these feel-good items inside: lip balm since your lips may become very dry, even before you start breathing heavily during labor; bands or scrunchies to keep your hair back; a brush for tangles (plus having someone brush your hair may feel relaxing); moisturizer; warm socks and slippers; mints; flip-flops (if your feet swell) and a warm robe.

They just might make your labor, delivery and overall stay more comfortable. Remember, don't bring or wear anything you really love, like your favorite PJs or that fancy negligee, since it may get lost or ruined.

Prepare a birth plan

You've read all you can about pregnancy and childbirth, you've prepped for labor and delivery as well as anyone can and you're pretty sure you know exactly how you'd like the birth of your baby to go — from the first contraction to the last push.

That’s where a birth plan comes in. Like the name suggests, a birth plan is a written plan that clearly states your preferences for before, during and after labor and delivery. After all, the best plan is to have a plan, so start thinking now about how you'd like the experience to go.

Remember to be flexible, though. Even the best-laid plans can change at the last minute — so you’ll need to check your childbirth ideals at the hospital and let the doctors, nurses or midwives make the best decisions for you and your baby’s health.

Visit the dentist

Teeth cleanings are a good thing — especially because about 40 percent of the pregnant set have periodontal disease, which ups their chance of preeclampsia (a pregnancy complication that's characterized by high blood pressure).

Dental X-rays should be saved until after baby arrives, though, unless the risk of not having one done outweighs the relatively small risk of radiation to the fetus.

If you do have an X-ray, wear a lead apron or abdominal shield over your lower belly.

Choose comfortable shoes

The best prescription for swollen feet and ankles isn't the most fashionable one: sensible, comfortable shoes that breathe and aren't too tight. Don't have any that fit that description? That might be because your feet have grown a half size or so.

Get yourself to a shoe store — but do it at the end of the day, when your feet are at their puffiest. While you're at it, get a pair of elasticized slippers and wear them whenever you can get away with it. And be sure to have some flip-flops on hand for postpartum swelling of the feet and ankles, which can happen as the pregnancy fluids are leaving your body after you give birth.

You can also try support hose to relieve pregnancy swelling. No they’re not sexy, but they can be the difference between a swell day and a not-so-swell one. Put them on first thing in the morning, before your feet have a chance to puff up.

If you can't track down ones made for pregnancy, knee- or thigh-highs should do the trick. But avoid any that have uncomfortable elastic tops.

Learn early labor signs

Unless you’ve gone into labor before, you're probably wondering how you'll know your labor symptoms are the real thing.

Learn the signs of labor in case it’s not obvious: contractions coming regularly and at closer intervals, period-like cramps, vaginal bleeding or spotting, a constant dull backache, diarrhea and a tightening feeling in your uterus. Your water might even break before you get to the hospital, though don’t count on that!

Do simple stretches

Chances are, you’re carrying a lot of tension in your neck, especially now that you’re in the third trimester and your posture is off-kilter. The result can be, well, a pain in the neck.

One way to loosen your muscles and relax your mind: Do this easy stretch — anytime, anywhere. Start by tilting your head to one side, without raising your shoulders; try to lower them down the back instead. Hold for three seconds and exhale. Repeat on the other side.

Do this several times a day — at your desk, while you're waiting at your practitioner's office, or in line at the post office.

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You're Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.

  1. What to Expect When You're Expecting, 5th edition, Heidi Murkoff.
  2. WhatToExpect.com, Safe Sleep Tips for Babies, June 2022.
  3. WhatToExpect.com, Hospital Bag Checklist, October 2023.
  4. WhatToExpect.com, What to Pack in Your Hospital Bag During the COVID-19 Pandemic, May 2022.
  5. WhatToExpect.com, How Much Water Should You Drink During Pregnancy?, November 2022.
  6. WhatToExpect.com, The Best Stretches to Do During Pregnancy, September 2022.
  7. WhatToExpect.com, Edema (Swelling of the Ankles and Feet) During Pregnancy, October 2022
  8. WhatToExpect.com, Is Postpartum Swelling Normal?, February 2022
  9. WhatToExpect.com, Fatigue During Pregnancy, November 2022.
  10. American College of Obstetricians and Gynecologists, How Your Fetus Grows During Pregnancy, December 2021.
  11. American College of Obstetricians and Gynecologists, Preeclampsia and High Blood Pressure During Pregnancy, April 2023.
  12. Centers for Disease Control and Prevention, Water and Healthier Drinks, June 2022.
  13. KidsHealth From Nemours, Bringing Your Baby Home, June 2018.
  14. Mayo Clinic, Fetal Development: The 3rd Trimester, June 2022.
  15. Mayo Clinic, Sex During Pregnancy: What's OK, What's Not, July 2022.
  16. Mayo Clinic, Varicose Veins, March 2022.
  17. National Heart, Lung, and Blood Institute, The Lungs, March 2022.
  18. National Institutes of Health, National Heart, Lung, and Blood Institute, Varicose Veins, September 2023.
  19. National Institutes of Health, National Library of Medicine, Dehydration, May 2019.
  20. National Institutes of Health, National Library of Medicine, Sex in Pregnancy, April 2011.
  21. The Urban Child Institute, Baby's Brain Begins Now: Conception to Age 3.
  22. American Journal of Radiology, Change in Brain Size During and After Pregnancy: Study in Healthy Women and Women with Preeclampsia, January 2002.
  23. JAMA Pediatrics, Denouement and Discussion: Congenital Sucking Blisters, June 2007.
  24. National Institutes of Health, National Library of Medicine, Pediatrics, Prenatal and Postnatal Flavor Learning by Human Infants, June 2001.
  25. National Institutes of Health, National Library of Medicine, Symmetrical Erosions in a Neonate: A Case of Neonatal Sucking Blisters, July 1998.
  26. WhatToExpect.com, Changes or Decreases in Fetal Movement, February 2023.
  27. WhatToExpect.com, Frequent Urination During Pregnancy, September 2022.
  28. WhatToExpect.com, How Many Weeks, Months and Trimesters in a Pregnancy?, May 2022.
  29. WhatToExpect.com, When Does Your Baby Develop a Brain?, June 2021.
  30. WhatToExpect.com, Shortness of Breath During Pregnancy, September 2022.
  31. WhatToExpect.com, When Does Baby Drop and What Is "Lightening" During Pregnancy?, February 2023.
  32. WhatToExpect.com, How to Create a Birth Plan, June 2021.
  33. WhatToExpect.com, Sore and Bleeding Gums During Pregnancy, January 2022.
  34. WhatToExpect.com, Best Shoes for Pregnancy, According to a Podiatrist, March 2023.
  35. WhatToExpect.com, Signs of Labor, August 2021.

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