31 weeks pregnant: baby, body and what to expect

Trimester 3 of 3About 7 months9 weeks to go

Week 31 of pregnancy: baby is about the size of a coconut

Week 31 at a glance

At 31 weeks, some babies move or change activity when bright light is shined on the belly, which shows the senses and nervous system are still maturing. Bleeding, fluid leaking, severe pain, regular contractions, or fewer movements mean you should call your provider.

31 weeks pregnant is about 7 months. You are in month 8 of pregnancy and the third trimester.

Your baby at 31 weeks

How your baby's senses are developing

31 weeks: how baby may respond

By 31 weeks, your baby can notice more outside stimuli. Some babies move or change their activity when bright light is shined on the belly. Research on this is limited, so it is not a reliable health check on its own. It mainly shows that the nervous system and senses are still maturing.

What often happens this week

The visual system keeps developing and becomes more sensitive to light.
The brain and muscles coordinate movements better.
Your baby may respond to sound and touch as well as light.
Body fat continues to build, which helps after birth.
Sleep and wake cycles may become easier to notice.

Call your provider right away if you notice bleeding, fluid leaking from the vagina, strong pain, regular contractions, or a clear drop in your baby's movements. Many providers recommend counting movements each day and asking what to do if the count seems lower than usual.

Responses to light vary a lot from one baby to another, and many babies respond differently from day to day. If something feels unusual, an in-person check gives more clarity than watching at home. Ask your OB-GYN or midwife any questions you have at your next visit.

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Your body at 31 weeks

Tips for Relief

Why does heartburn happen?

At 31 weeks of pregnancy, many people notice heartburn (a burning feeling in the chest, behind the breastbone). The growing uterus pushes up on the stomach, and the hormone progesterone relaxes the valve between the stomach and the esophagus. Together, these can let stomach acid travel upward.

Ways to find relief

Eat smaller, more frequent meals. A very full stomach can make reflux worse.
Notice your triggers. Many people find that fatty or spicy foods, acidic foods, caffeine, and chocolate make symptoms worse.
Stay upright after eating. Try to stay sitting or standing for about an hour after meals.
Raise your head while you sleep. Extra pillows or a wedge can help keep your upper body elevated. Many people also find sleeping on the left side more comfortable.

Heartburn that becomes severe, disrupts your sleep, or does not improve may need medical care. Ask your doctor which antacids are safe to use during pregnancy. Call your provider right away if you have chest pain or pressure, trouble breathing, trouble swallowing, vomiting, or black or bloody stools. These symptoms can have causes other than heartburn.

Common symptoms at 31 weeks

Heartburn

A growing uterus and pregnancy hormones can make stomach acid rise into the chest. Smaller meals, staying upright for a while after eating, and raising the head of the bed may help.

Shortness of breath

As the baby grows, the uterus presses up under the lungs, so you may feel winded with stairs or walking. Slowing down, sitting upright, and taking breaks often helps, and you can mention it at your next visit.

Swelling in feet and ankles

Some swelling is common later in pregnancy, especially by the end of the day. Elevating your legs, staying active, and drinking water may ease it, but sudden swelling in the face or hands should be reported to your provider right away.

Tightening of the belly

Irregular, painless tightenings called Braxton Hicks contractions are common now. They usually ease with rest or a change of position, but regular, painful contractions need a call to your provider.

Frequent urination and back ache

The baby's weight on the bladder can make you run to the bathroom more often, and your posture may shift as your belly grows. A supportive pillow and changing positions often helps.

Your week 31 checklist

Start a simple kick count or movement log and learn what your baby's usual pattern feels like. Write down your provider's after-hours number and keep it where you can reach it quickly. Begin a list of hospital bag items and what to bring for your baby. Plan a time to talk with your partner or support person about your hopes for the birth. Ask your provider which antacids are considered safe for you if heartburn is bothering you. Look into your insurance coverage for childbirth classes or a car seat check.

Tests and appointments

Tdap vaccine. Many providers offer the whooping cough (Tdap) vaccine between 27 and 36 weeks so that protective antibodies can pass to the baby.
Growth ultrasound. Some providers schedule an ultrasound around this time to check the baby's growth, position, and the amount of amniotic fluid, depending on your needs.

For your partner: You can help by taking on tasks that get harder with a bigger belly, such as carrying groceries, cleaning, or handling the laundry. Offering to attend appointments and keep track of movements or questions for the provider can also ease the load.

Questions about week 31

How many months is 31 weeks pregnant?

31 weeks pregnant is about 7 months. You are in month 8 of pregnancy and the third trimester.

What trimester is 31 weeks?

Week 31 is in the third trimester. The first trimester runs through week 13, the second from week 14 to 27 and the third from week 28 until birth.

What is happening with the baby at 31 weeks?

At 31 weeks, some babies move or change activity when bright light is shined on the belly, which shows the senses and nervous system are still maturing. Bleeding, fluid leaking, severe pain, regular contractions, or fewer movements mean you should call your provider.

Is swelling in my feet normal at 31 weeks?

Mild swelling in the feet and ankles is common at this stage, especially later in the day or in warm weather. Tell your provider if swelling is sudden, affects your face or hands, or comes with headache or vision changes.

Can I take antacids for heartburn at 31 weeks?

Some antacids are commonly used in pregnancy, but others are not recommended. Check with your provider or pharmacist before taking any medicine, including store-bought products, so you choose one that fits your situation.

Is it safe to travel by car at 31 weeks?

Many people can still travel at this stage, but plan regular breaks to stretch and walk. Always wear a seatbelt with the lap belt low across your hips and the shoulder belt between your breasts, and ask your provider if you have questions.

Safe or not?

LimitCan I eat brie while pregnant?AvoidCan I eat smoked salmon while pregnant?LimitCan you drink energy drinks while pregnant?LimitCan you eat tuna while pregnant?

Guides for this stage

Medical careBirth plan: how to make a document for your care team ExerciseBreathing Techniques for Labor Contractions and Pushing Trying to conceiveCord Blood Banking: Is a Storage Contract Worth It?Medical careWhat fetal heart rate monitoring is and why it is often used near the end of pregnancy

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Learn more

NIH: Pregnancy (NICHD)
CDC: Pregnancy

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General information only; it does not replace advice from your doctor or midwife.