Pregnancy Week 40

Now that you're 40 weeks pregnant, your baby is finally ready to meet you! Learn why you may need to induce labor if you're overdue in week 40.

Week by week baby size image. Week by week baby size image.

How big is baby?

By the time she's born, your baby may be watermelon-size. You're expecting to give birth this week, but don't worry if your baby decides to stick around a little longer. Many first babies are late, and she'll be worth the wait—we promise!

Baby's Length: 20.16in.
Baby's Weight: 7.63lb.
Fetus at Week 40 What the baby looks like at week 40 of fetal development. Med ART Studios Explore More

Baby's Development

When your baby arrives, she will be evaluated and graded (zero to two points each) on the following factors: activity and muscle tone, pulse (heart rate), grimace response (medically known as "reflex irritability"), appearance (skin coloration) and respiration (breathing rate and effort). This sum will determine the baby's Apgar score, an initial measure of her health. Most healthy babies have an Apgar between seven and nine (few babies get a 10).

Baby Week 40

Congratulations on reaching your estimated due date! Most babies born at 40 weeks weigh between 7 and 9 pounds.Your baby's brain has developed remarkably over the past 9 months, but it will continue to expand crucial neural pathways for the next few years following birth.Your baby's head is considered engaged when it is down past the pelvis. This usually occurs prior to labor as the baby begins to enter the birth canal.
Week by week baby ultrasound image. Week by week baby ultrasound image. American Institute of Ultrasound in Medicine -

Week 40 Ultrasound

If your healthcare provider wants to get an idea of your baby's weight, one of the most important measurements the sonographer can take is the abdominal circumference. This image is a cross section of your baby's belly. The small back oval is her stomach, and the curved black line is the blood vessel that brings nutrients from the placenta. Soon, you'll have a very different way of feeding her! 

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Watch Baby's Growth

What Week 40 of Your Pregnancy is Really Like

Mom's changing body

Your baby is due this week, and if you're lucky she will actually arrive this week! Soon you'll feel your first real contractions. They'll come fast and furious once you're in active labor, lasting up to a minute each, or even a bit longer. And yes, they huuuurt. You'll feel this intense pain radiating through your stomach, lower back and upper thighs. This is like nothing you've ever felt before, and each woman copes with it differently. Now's the time when pain-relieving epidurals are usually administered, so don't be afraid to ask for one. While your baby gets the once-over, you'll be busy delivering the placenta,  the 2-pound, bluish mass of blood vessels and tissues that has nourished and protected your infant over the past nine months. Although you may continue to feel contractions, most new moms are too blissed out — "I did it! She's here, she's healthy, she's gorgeous!" — to notice them.

Weekly Tip

Once you get to the hospital, a doctor will check things out down there to see how much your cervix has dilated. Once you reach 3 or 4 centimeters, you'll likely be offered an epidural to help manage the pain. (According to the many women who swear by them, the needle prick of the local anesthetic going in before they give you the epidural may be the most painful part of your entire labor.) Or, you may be set on delivering drug-free. No matter what you've planned or imagined, it's perfectly fine to change your mind at the last minute. It happens a lot!

Pregnancy Confidential Podcast

To Induce or Not to Induce? That is the Million Dollar Question.

You've made it to your due date! Congrats. But the fact that you're still listening to this tells us you're not exactly in the throes of labor—yet. Reaching Week 40 and beyond can be a frustrating time. You can feel as big as a house with a four-­car garage and totally, 100% ready to get this birthing show on the road. Like NOW. In our last episode, we covered the lovely, laid­-back things you can do naturally to coax your body into labor, but now that you've hit D­-day, it's time to get serious. Do you induce or don't you? And if so, how long do you go before the P­-word (Pitocin) is uttered? Remember: it'll all be worth it once you're holding that baby!

This Week's To-Do List