Pregnancy Week by Week – Weeks 37 to 40

This is it! Learn what to expect in these last few weeks before your baby arrives.

You’re in the final weeks of your pregnancy. Soon, you’ll get to meet that baby boy or girl who’s been kicking up a storm inside your womb! Just in case you go into labor early, make sure all the final preparations are ready for your new arrival. Line up help – either from a family member or paid nanny, because you’ll likely need it during your baby’s first few days and weeks. Stock up on frozen meals that you can quickly pop into the microwave or oven. And, make sure you have all your baby supplies on hand.

Here’s a look at what’s happening week by week with your baby – and your body – this month.

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Weeks 37 - 38

Both your body and baby are making their final preparations for labor. Your little one is now considered full-term. Although she will likely stick around in your womb for a few more weeks, she could survive on the outside if she were born today.

By now, your baby should have shifted into a head-down position. You’ll notice a number of physical changes under way. For one thing, your cervix – the passageway out of your uterus – will widen to accommodate your baby’s body. Watch for the first signs of labor (see below), and report them to your doctor.

Your body

Contractions might be coming more frequently now. These are likely still Braxton-Hicks, or false contractions, and not the real things. You can tell the difference by the frequency and intensity. If the squeezing comes and goes at irregular times and it isn’t very painful, they’re likely Braxton-Hicks. Real contractions come at regular intervals – like every 5 minutes or every 3 minutes. Each one lasts between 30 and 70 seconds. If you’re in true labor, the contractions will gradually intensify and come closer and closer together. Then it’s time to call the doctor.

At around this point in your pregnancy, you might discover a blob of blood-tinged mucus in your underwear. Don’t panic. This is called the mucus plug, and it’s perfectly normal. During your pregnancy, this plug prevented bacteria from getting into your uterus and causing an infection. As your cervix widens in preparation for delivery, the plug will slip out. Your mucus plug isn’t necessarily a sign of impending labor, although it can be.

Your baby

By week 38, your baby weighs about 6 ¼ to 7 ½ pounds and measures 20 inches long. Now that baby is taking up more space in your uterus, she’s leaving less room for amniotic fluid. As a result of her more cramped accommodations, her movements won’t be as big as they were a few weeks ago, but you should still feel her shift from position to position. If the movements slow or stop, call your doctor right away.

Your baby should have shifted into a head-down position. If she hasn’t moved down yet, ask your doctor about methods to move her and avoid a breech (buttocks or feet-first) delivery.

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Weeks 39 - 40

You’re in the home stretch! In just two weeks (give or take a few days), you’ll finally meet your baby. Pack your bags for the hospital and have them ready by the door. Labor could come at any time now.

Your body

As you approach your delivery date, you’ll likely feel all the discomforts of late pregnancy – the swollen feet and ankles, constant urge to use the bathroom, difficulty breathing, hemorrhoids, heartburn, and trouble sleeping. Know that these complaints are only temporary, but try to take it easy for these last couple of weeks.

As your cervix prepares for delivery, it will efface or “ripen” – meaning it will get softer, shorter, and thinner. When you go into labor, you might hear your delivery team refer to your cervix as “25 percent” or “50 percent” effaced. Once you are 100 percent effaced, you’ll be ready to deliver.

Your baby

On average, babies at this stage of pregnancy weigh between 6 3/4 and 10 pounds and measure 19 to 21 inches long – though your baby might be smaller or larger than the average. Your baby’s bones have hardened – with the exception of his skull, which still needs to remain pliable to get through the birth canal. He’s got a thick layer of fat under his skin now, so he can regulate his temperature on the outside.

What to remember

Babies don’t always arrive on time. If this is your first pregnancy or your family members have delivered late, you might do the same. You’ll continue with your weekly prenatal visits past your due date. Ask your doctor what you should do if you reach the 40-week mark without going into labor. The doctor will look for any possible complications, and track your baby’s heart rate and other vital signs. If your pregnancy goes beyond 42 weeks or you have any complications, the doctor might decide to induce labor.

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