Week 31
Your baby is the size of a coconut
What's happening this week
Your baby is about 16.5 inches from head to toe and weighs roughly 3.3 pounds. And this week comes with a reassuring milestone: most major development is now complete. From here until birth, the primary task is gaining weight and maturing the organs that need the most time — specifically the lungs and the brain.
Your baby is gaining weight rapidly, adding about half a pound per week. Much of this weight is fat, which accumulates under the skin and gives your baby the round, plump appearance you'll see at birth. This fat layer is critical for temperature regulation after birth, when your baby will no longer have the warmth of your body surrounding them.
The brain can now process a remarkable amount of information. Your baby responds to light, sound, and touch with increasingly complex reactions. They can distinguish between different sounds and may even show preferences — turning toward familiar voices and startling at unexpected loud noises. Sleep patterns are well established, with distinct cycles of active sleep (similar to REM) and quiet sleep.
In baby boys, the testicles are continuing their descent from the abdominal cavity into the scrotum. This process typically completes before birth, though some boys are born with undescended testicles that resolve in the first months of life.
Your baby is running out of room. The amniotic sac that once had plenty of space for somersaults is getting crowded. Your baby can still move — kicks, punches, and rolls are frequent and strong — but the big flips and turns are becoming less common. You may feel more distinct, pointed movements (an elbow here, a foot there) rather than the rolling sensations of earlier weeks.
Your body this week
Nine weeks to go, and your body is working overtime. You may be gaining about a pound per week, and much of that is your baby's rapidly increasing weight plus the additional blood, fluid, and tissue your body is producing to support the pregnancy.
Sleep continues to be one of the biggest challenges. Between the belly, the back pain, the leg cramps, the bathroom trips, and the sheer difficulty of getting comfortable, many parents-to-be get only fragmented rest. A pregnancy pillow, keeping the bedroom cool, and going to bed earlier than usual (even if you wake up multiple times) can help maximize the sleep you do get.
You may notice your belly button has popped out — if it hasn't already. This is caused by the expanding uterus pushing outward. It typically returns to its normal position after delivery, though it may look slightly different than before.
Swelling in the feet and ankles may be more persistent, especially at the end of the day. Continue to elevate your feet when you can, stay hydrated, and avoid standing for long periods. Sudden, severe swelling — especially in the face and hands — warrants an immediate call to your provider, as it can be a sign of preeclampsia.
Your provider visits are now every two weeks, and they're likely becoming more focused on your baby's position, your blood pressure, and signs of any late-pregnancy complications. This increased monitoring is routine and reassuring — not cause for alarm.
For dads
Nine weeks out. The baby is now over 3 pounds and gaining half a pound per week. Your partner can feel every ounce of that growth — in her back, her hips, her bladder, and her ability to sleep. She may be increasingly uncomfortable and increasingly over being pregnant. That's valid. Don't try to cheer her up with 'it'll be worth it' — she knows that. What she needs is acknowledgment: 'I know this is hard, and you're doing an incredible job.' Practically: if the nursery isn't ready, finish it. If the car seat isn't installed, install it. If you haven't toured the hospital, call and schedule. Every task you complete now is one fewer thing to worry about when labor starts — which could theoretically happen any time in the next 6-9 weeks.
Start thinking about your support system for after the baby arrives. Who can bring meals? Who can help with older children or pets? Who can your partner call at 2 AM when she needs to talk to another parent? Having these people identified and on standby before the birth makes the postpartum period significantly less overwhelming. Don't wait for people to offer — reach out and ask. Most friends and family members are eager to help but don't know what you need. Tell them specifically: 'We'd love a few freezer meals' or 'Could you walk the dog twice a day the first week?'
Common concerns
Is it normal for kicks to feel different now?+
Yes — as your baby grows and runs out of room in the amniotic sac, the nature of movements changes. Instead of the big rolls and somersaults of earlier weeks, you may feel more distinct jabs, pokes, and pushes — sometimes you can even identify a foot or elbow pressing against your belly. This is normal. What matters most is that your baby maintains their usual level of activity. If you notice a significant decrease in movement, contact your provider.
What happens at prenatal visits from here?+
Third-trimester prenatal visits become more frequent (every 2 weeks now, weekly starting around 36 weeks) and more focused. Your provider will check your blood pressure, test your urine for protein (a preeclampsia indicator), measure your fundal height, listen to the baby's heartbeat, and assess the baby's position. Starting around 36 weeks, your provider may also check for cervical changes. These visits are routine monitoring — not a sign that something is wrong.
Should I be worried if my baby hasn't turned head-down?+
At 31 weeks, many babies are still experimenting with different positions. Most settle into a head-down (vertex) position by 34-36 weeks. If your baby is still breech after 36 weeks, your provider may recommend specific exercises, the Spinning Babies technique, or external cephalic version (ECV) — a procedure where a provider manually guides the baby into a head-down position. For now, there's no cause for concern.
When should I call about swelling?+
Mild swelling in the feet, ankles, and hands is normal in the third trimester. However, call your provider right away if swelling is sudden or severe, appears in your face (especially around the eyes), is accompanied by headache or vision changes, or occurs in just one leg. Sudden facial swelling with headache can be a sign of preeclampsia, which requires immediate evaluation. Gradual, symmetrical swelling that worsens throughout the day and improves with rest and elevation is typically normal.
Product picks for week 31
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Postpartum meal delivery gift card
Line up freezer meals or a meal delivery service for after the baby arrives — cooking will be the last thing on your mind.
Infant first aid kit
A baby-specific first aid kit with a nasal aspirator, thermometer, nail clippers, and medicine dispenser — essentials for the early weeks.
White noise machine
Studies show white noise helps newborns sleep by mimicking the constant sound environment of the womb — get one set up now.
A quick note: This content is for informational purposes only and is not a substitute for professional medical advice. Always talk to your healthcare provider about any questions or concerns. Learn how we create our content.
Content based on guidance from the American College of Obstetricians and Gynecologists (ACOG), the American Academy of Pediatrics (AAP), Mayo Clinic, and peer-reviewed medical literature. Learn more about how we create our content.