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40 Weeks Pregnant: Week-by-Week Guide
5 mins read

IN THIS ARTICLE – At this stage of your journey, new developments are beginning to unfold. Check out this week-by-week guide to find out what’s in store for your baby and your body in week 40 of pregnancy.


Your baby at 40 weeks pregnant | Week 40 pregnancy symptoms | Your newborn at birth | Baby brain waves | Mom's tip of the week | Pregnancy health | Join Enfamil Family Beginnings


  • What trimester is 40 weeks? Third trimester
  • How many weeks of pregnancy are left? Technically zero, unless the baby takes their time arriving.
  • How many months is 40 weeks pregnant? You have completed your ninth month.

With week 39 of your pregnancy complete, you’re on week 40. Enjoy it—you’re about to have a newborn!

One of the most exciting things about pregnancy is how many changes you’ll experience with your little one over the span of just 7 days! Here’s some tips and tricks to keep on top of all that’s happening.

Your baby at 40 weeks pregnant

What's happening in there

  • Your baby is the size of a jackfruit.
  • You’re officially at the end of your pregnancy.
  • Ready to go: Your baby will be making their debut.

What happens during the 40th week of pregnancy?

  • Full term, baby: At 40 weeks, your baby has reached their due date and is considered “full term.”
  • Love at first sight: You may finally meet and cuddle your beautiful bundle of joy who’s been growing inside you for so long.
  • Fashionably late: Mother Nature doesn’t always stick to a timeline. At 40 weeks pregnant, your baby may need a little more time. In fact, only 5% of babies are born on their due date, and a good number arrive up to two weeks past their due date.
  • Get ready: The wonder is just beginning. Your baby will start exploring the world, and you’ll be doting on every sweet discovery.
  • Final check-ins: Is it past your due date? Your doctor may want to do a Biophysical Profile, an ultrasound and a non-stress test that evaluates your baby's health, such as their heart rate.

What should I be feeling at 40 weeks pregnant?

  • You may start to experience signs of labor. Call your doctor if you begin having regular contractions or if your water breaks.
  • Being both excited and anxious is normal. Try to ease your mind by talking to your family or friends about concerns, meditating, and incorporating other stress-reducing strategies.

40 weeks pregnant belly

Your uterus has expanded to the size of a watermelon. To accommodate your baby, it now extends from your pubic area to the rib cage.

How big is your baby at 40 weeks pregnant?

40 Weeks Pregnant

Baby Weight

6.5 to 9 pounds

Baby Length

20 to 22 inches

Baby Size

Comparable to a jackfruit

Week 40 pregnancy symptoms

During week 40 of pregnancy, your body is changing quickly. As your baby grows, you will too, and there are certain pregnancy symptoms you may experience at this time.

  • Along with stretch marks, some moms-to-be develop pruritic urticarial papules, or PUPPP. Also known as polymorphic eruption of pregnancy (PEP), this is a harmless but uncomfortable itchy rash. PUPPP can appear late in the third trimester and sometimes early postpartum. If you have this type of rash, speak to your doctor for diagnosis and treatment options.
  • You may still be having Braxton Hicks contractions, infrequent and unpredictable contractions that are uncomfortable rather than painful. However, at this late stage, contractions can mean you’re in labor. True labor contractions will feel stronger, last longer, and become closer together.
  • Your breasts may be leaking colostrum, a waxy, yellow liquid that’s chock-full of important benefits for newborns.
  • As your baby kicks, you may experience rib pain. Applying a cooling pack to your ribs may provide some relief.
  • Exhaustion, backaches, pelvic pain, swollen hands and feet, and feeling uncomfortable overall are typical symptoms during week 40. Your body has been working overtime for nine months, but hang in there; the baby will be here before you know it!

Your newborn at birth

  1. Newborn baby sizes vary. The average baby weighs 6.5 to 9 pounds and measures 20 to 22 inches at 40 weeks.
  2. Your baby’s skin may not look like you expected. They are covered in vernix, a protective white, waxy substance, until their first bath. Even after that, their skin may be mottled in some places and blue in others (due to immature circulation), and they may have dry patches.
  3. Your baby's genitals may be enlarged. Thanks to pregnancy hormones in your baby's system (which is normal), they may have temporarily enlarged genitals at birth.
  4. Their vision is a little blurry. After your baby's birth, they will only be able to focus on objects 8 to 12 inches from their face, which is exactly how far your face is from theirs when you are feeding them. With time and good nutrition, their vision will mature.
  5. DHA from breast milk or infant formula is still important to help support brain development. You can continue taking a prenatal supplement that has DHA. DHA can also help support a baby's vision development.
  6. Your baby will recognize the familiar sound of your voice. So go ahead and start talking to your little one right away.

Baby brain waves

Your baby’s brain is developing.

At 40 weeks, your baby has quite the brain already. However, while your baby’s brain has undergone an amazing transformation throughout your pregnancy, it still has a long way to go. When they are born, most of your baby’s actions are controlled by the lower brain and are called reflexes. Here are some of the actions you’ll see your newborn do:

  • Turn their head toward and suck on an object placed near their mouth (known as the rooting reflex)
  • Throw out their arms and legs when startled by something (the Moro reflex)
  • If you support their body and head and let the soles of their feet touch a flat surface, they will make walking motions (the stepping reflex)

As the upper regions of your little one’s brain mature, they will lose these reflexes and begin controlling their actions more and more.

Mom's tip of the week

Did you know...?

Your baby will need lots of attention right after they are born. They’re ready to be loved. Here’s some of what you can expect after delivery:

  • Your doctor will suction the mucus out of your baby’s mouth and nose, and then you’ll hear your little peanut’s voice at last.
  • The umbilical cord will be cut (by a parent or doctor).
  • Your baby will be whisked away for a few quick screening tests to make sure everything is OK.
  • After that, they’re all yours!

Pregnancy health

Real issues, real solutions

The issue: At 40 weeks pregnant, you're about to meet your newborn baby, and you're not sure what to expect.

The solution: Although babies develop at different rates, they all experience some rapid changes right after birth in four key areas controlled by the brain. Development in these areas—cognitive, motor, social, and communication—are measured in age‐related milestones. Take a peek at some simple things you can do to support your baby's growth.

More info you might find helpful:

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All information on Enfamil, including but not limited to information about health, medical conditions, and nutrition, is intended for your general knowledge and is not a substitute for a healthcare professional's medical identification, advice, or management for specific medical conditions. You should seek medical care and consult your doctor or pediatrician for any specific health or nutrition issues. Never disregard professional medical advice or delay seeking medical treatment, care, or help because of information you have read on Enfamil.