40 Weeks Pregnant
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Baby is as big as a watermelon
You’re Almost There!
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June 8, 2022

40 Weeks Pregnant

Happy due date! Since 40 weeks pregnant is baby’s official deadline, you’ve already made up the bassinet, installed baby’s car seat, packed your hospital bag and set it by the door. Now, take care of some easy last-minute things, like making sure your cell phone is fully charged before you go to bed.

Week 40 of pregnancy can be mentally rough, since you’ll be constantly wondering when baby will decide to make their entrance and question every twinge you have. Pay close attention to fetal movement. If you notice a decrease in the way baby moves, call your heathcare provider immediately. Try not to stress, and rest assured that baby will arrive when they’re ready—and your body will give you the right signals that it’s time.

How Big Is Baby at 40 Weeks Pregnant?

At 40 weeks pregnant, baby is the size of a watermelon. The average full-term 40- week baby measures about 20.2 inches from crown to heel and weighs 7.6 pounds.

40 Weeks Pregnant Is How Many Months?

You guessed it—at 40 weeks pregnant, you’ve completed the nine+ months of pregnancy! You made it!

3D Views: My Baby, My Body

See their progress for yourself with our 3D interactive tool.

40 Weeks Pregnant Symptoms

During these last weeks of pregnancy, the same symptoms you’ve been having will likely continue. Your main job is to hang in there as you keep experiencing these:

  • Leg cramps. Stick with the calf and hamstring stretches to keep leg cramps from messing with your sleep.
  • Pelvic pressure. Baby may drop even lower in your pelvis, making your pelvic discomfort worse.
  • Trouble sleeping. If you can’t sleep, it’s okay to get up and do something else, but keep to a calming activity such as reading or writing in a journal. Don’t start cleaning out your freezer or doing a Zumba video. Rest.
  • Fatigue. The fact that you can’t sleep isn’t really helping here. But since you may not have any plans, you may be able to sneak in an extra nap here or there—or at least take some quiet time to relax when you’re tired.
  • Contractions. Those Braxton Hicks contractions may eventually turn into the real deal, so if it seems like you’re having a lot of them, start timing them to see how far apart they are. If they get closer together and start to feel painful, you’re in an early stage of labor.
  • Anxiety! Baby will get here when they get here. Do your best not to stress.

Of course! (Although at this point, it may feel like you’ve been pregnant forever.) Sometimes, the timing for pregnancy can be confusing. You may hear people talk about it lasting for “nine months,” but a normal pregnancy lasts 40 weeks—and that’s longer than nine months. That’s why your OB has been referring to each stage of your pregnancy in weeks, not months. It may feel like baby’s taking a long time in there, but at 40 weeks, they’re right on time!

40 Weeks Pregnant Signs of Labor

You might be 40 weeks pregnant with no signs of labor. But at 40 weeks pregnant, signs of labor will be here very soon. Call your doctor right away if you have contractions that are more than a little uncomfortable or keep coming at regular intervals. The other 40 weeks pregnant sign of labor to look out for? A leak or flow of amniotic fluid—this means your water has ruptured or broken. You’ll likely know because it will be truly watery, not like typical discharge, and it doesn’t stop. At first you might think it’s pee, but then you will realize—nope! You’re in labor! Call your OB.

Inducing Labor at 40 Weeks Pregnant

At 40 weeks pregnant, you may be getting antsy—after all, this is supposed to be your last week of pregnancy! You may be curious how to induce labor using natural methods. We recommend taking long walks and having sex. (Both are fun pastimes and could cause your body to start the process.) If you want to try acupuncture, that’s considered safe too. However, don’t take herbal supplements or drink castor oil—doctors say those methods are unsafe and probably won’t work anyhow. You might have heard that stimulating your nipples can induce labor. It can, but doctors recommend you don’t even try it. In fact, nipple stimulation can cause contractions that are too strong and may put baby’s well-being in jeopardy—not worth it.

Now that you’ve reached your due date, your doctor might talk to you about inducing labor medically. Whether or not this is necessary will have to do with how baby is doing in there. (The doctor might schedule this now if you have complications or are 40 weeks pregnant with twins.) If baby is perfectly healthy and you have no complications, you might not need an induction at all and can keep sticking it out, even if it takes a couple more weeks. (Yes, weeks. Though chances are high that you’ll go into labor naturally by the end of next week.) It might be worth it to know that you waited it out until baby was truly ready.

What Causes a Baby to Be Overdue?

There’s no one particular reason why baby misses their due date. It could run in your family; maybe you were even born late! It also can occur during first-time pregnancies or if you had a prior pregnancy where baby showed up late. Baby’s sex can also play a role, as some believe boys are more likely than girls to make a delayed arrival. And frequently, confusion over the date of your last period can lead to miscalculation of your due date—in that case, baby’s not late at all!

40 Weeks Pregnant Ultrasound

Your 40-week fetus is continuing to grow hair and nails. And baby at 40 weeks is keeping up that lung development, too. Once you’ve completed a full-term pregnancy and reached 40 weeks, your doctor will likely want to do a biophysical profile. In case you missed it, this is a two-fold test. You’ll have a non-stress test, where baby’s movement and your contractions are monitored to see how baby’s heart rate reacts. Both a biophysical profile and NST are generally done twice a week once you’ve passed your due date. You’ll also have a 40 weeks pregnant ultrasound to see what the amniotic fluid levels look like.

If the results of the biophysical profile and non-stress test, and/or the 40 weeks pregnant ultrasound, suggest that baby would be better off “on the outside” than in utero, then an induction may be ordered. If everything looks good, you’re back to the waiting game. Hey, baby can’t stay in there forever!

How Long Does It Take to Go Into Labor After 40 Weeks?

Your baby is unique—and that means the timetable for their arrival is all their own. Generally, a baby can be born within two weeks of their due date before being considered “post-term,” or overdue. We know you want baby to just get here already, but hang in there! As long as you both are doing well and being monitored twice a week, there aren’t any specific risks in waiting for labor to start naturally up to two weeks after the due date.

Tips for 40 Weeks Pregnant

Re-make your bed
Just in case your water breaks in the middle of the night, be prepared and put a waterproof mattress cover on your bed. You may want to keep it on even after baby comes to catch other messes like breast milk, spit up and pee.

Say “ommmmm”
If you’re feeling anxious in advance of baby’s birth, take some time to chill out and relax. Find a meditation app you can use whenever you need to shut off the busyness inside your brain and focus on calming mindfulness. It’s also a great way to wind down for bedtime, and it may even help you catch some of that elusive sleep!

Let it go
When a contraction hits, you may tense your entire body to help you bear the pain. That can actually make matters worse, so instead try going the opposite direction and relaxing your body as much as possible. One way to help you do this: Close your eyes and mentally scan your body from head to toe, stopping at the places where you feel tense and releasing that tightness in your muscles. Pair it with some deep breathing, and before you know it, the contraction will be over.

Gas up the car
The last thing you want to do as you’re driving to the hospital is stop for gas. This is one of those simple chores you (or your partner!) can do this week so you’re ready to go when baby is on the way.

Pregnancy Checklist at 40 Weeks Pregnant

Reminders for the week:

Medical content was reviewed November 2020 by Sherry A. Ross, MD, an ob-gyn and women’s health expert at Providence Saint John’s Health Center in Santa Monica, California, and author of she-ology and she-ology, the she-quel: let’s continue the conversation.

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