40 weeks pregnant: baby, body and what to expect

Trimester 3 of 3About 9 months0 weeks to go

Week 40 of pregnancy: baby is about the size of a small watermelon

Week 40 at a glance

At 40 weeks, your due date has arrived, but it is still an estimate. If labor has not started, that is often still normal, but call your provider right away if you have bleeding, fluid leaking, strong pain, or noticeably fewer movements.

40 weeks pregnant is about 9 months. You are in month 10 of pregnancy and the third trimester.

Your baby at 40 weeks

Your due date is here, and baby is ready to meet you

40 weeks: your due date is here

Forty weeks is the estimated due date. Many families feel like this is the big day, but the date is only an estimate. A healthy baby may be born a little before or a little after it.

If labor has not started on your due date, that often does not mean there is a problem. Your provider will focus on your overall health, your baby's movement pattern, and whether any warning signs are present.

What may happen at this stage

Baby is fully grown and ready for birth. At this point, the average newborn weighs about 7 to 8 pounds and is about 20 inches long.
Movements may still be felt, even though there is less room to move.
Regular contractions and other signs of labor may begin.
The baby's head often drops lower into the pelvis.
Your body continues to prepare for birth.

Call your provider right away or go to the hospital if you have bleeding, fluid leaking from the vagina, strong or constant belly pain, regular contractions that are getting closer together, or noticeably fewer baby movements.

If you go past 41 weeks, many providers recommend closer monitoring, such as non-stress tests or ultrasound to check the baby's well-being and fluid levels. Many also talk with patients about induction of labor. Ask your provider what they recommend for you.

Try not to judge yourself too strictly by the calendar. Focus on how you feel and how your baby is moving, and keep in touch with your care team.

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Your body at 40 weeks

How Contractions Work and Signs of True Labor

How a Contraction Works

The uterus is a powerful muscle. During a contraction, the hormone oxytocin signals the muscle fibers to tighten and then relax. Over time, these repeated contractions help move the baby down and prepare the birth canal.

Cervical Changes

For the baby to be born, the cervix (the lower part of the uterus) needs to change in two main ways:

Effacement: The cervix softens, shortens, and thins out.
Dilation: The cervix opens from 0 to 10 cm (about 3.9 in).

Practice Contractions vs. True Labor

Many people have Braxton Hicks contractions, or practice contractions, in the later weeks of pregnancy. They are usually irregular and mild, and they often stop after rest or a change in position. True labor contractions tend to behave differently.

Signs of True Labor

They follow a regular pattern and get closer together.
Each contraction lasts longer, often 30 to 70 seconds.
They keep getting stronger, even when you rest or drink fluids.

Many healthcare providers use the 5-1-1 guideline: contractions about 5 minutes apart, lasting about 1 minute each, for at least 1 hour. If this pattern starts, many providers recommend calling your care team. Ask your provider which timing guidelines they use.

Call your provider or go to your labor and delivery unit right away if you have heavy bleeding, constant severe pain, a sudden decrease in fetal movement, or your water breaks. Tell your provider if the fluid is green or brown.

Common symptoms at 40 weeks

Irregular tightening (Braxton Hicks)

Your belly may feel tight or hard now and then without a steady pattern. These practice contractions often ease with rest, a change of position, or a drink of water.

Pelvic pressure

You may feel heavy pressure low in your pelvis as the baby settles lower. Changing position and taking short breaks can make this feel more comfortable.

Lower back ache

Back pain can come and go, and it may feel different from labor pain. Warm packs, gentle stretches, and a supportive pillow between your knees while lying on your side may help.

Loose stools or an upset stomach

Some people have diarrhea or nausea near the end of pregnancy. Small, bland meals and plenty of fluids are often easier on the stomach.

Mucus plug or light spotting

You may notice thick, clear, or pink-tinged discharge as the cervix softens. Call your provider if you see heavy bleeding or bright red blood.

Your week 40 checklist

Keep your hospital or birth center phone number and route written down or saved on your phone. Pack your hospital bag and place it near the door. Install and check your car seat, and make sure it is safely secured. Save a contraction timing app or notes sheet so you can track the pattern. Rest when you can, and plan simple meals you can eat easily. Write down your provider's after-hours number and what to say when you call.

Tests and appointments

Nonstress test or biophysical profile. If your provider recommends it, this checks the baby's heart rate and movement, and it is often offered if the pregnancy goes past your due date.
Cervical check. Your provider may check how soft, thin, and open your cervix is, which can help show how close labor may be.

For your partner: Stay close and ask what would feel helpful, such as timing contractions, bringing snacks, or handling calls. Keep the hospital route, bag, and car seat plan ready so you can both move quickly when it is time.

Questions about week 40

How many months is 40 weeks pregnant?

40 weeks pregnant is about 9 months. You are in month 10 of pregnancy and the third trimester.

What trimester is 40 weeks?

Week 40 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 40 weeks?

At 40 weeks, your due date has arrived, but it is still an estimate. If labor has not started, that is often still normal, but call your provider right away if you have bleeding, fluid leaking, strong pain, or noticeably fewer movements.

How do I tell Braxton Hicks from true labor?

True labor contractions get stronger, longer, and closer together over time, and they do not usually stop with rest or position changes. Braxton Hicks tend to be irregular and may fade. If you are not sure, call your provider for guidance.

Is it okay if the baby has not arrived by my due date?

Yes, many babies are born after the due date. The date is an estimate. Your provider will keep an eye on you and your baby and may suggest checks or a plan if the pregnancy goes on longer.

When should I call my provider about contractions?

Call when contractions become regular, or sooner if you have bleeding, fluid leaking, strong pain, or fewer baby movements. Your provider can tell you what to do based on your health and history.

Safe or not?

LimitCan I drink green tea while pregnant?Generally OKCan I eat pineapple while pregnant?Ask your doctorCan I paint while pregnant?Generally OKCan you eat mayonnaise when 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.