The countdown has begun: three weeks left to go. But don’t wish your pregnancy over quite yet. At 37 weeks, your baby is still not considered full term. As recently as October 2013, a baby born at 37 weeks was “full term,” according to the American College of Obstetricians/Gynecologists (ACOG). However, late in 2013, ACOG announced new definitions for “full term.” Here’s why. 

Your Body

your pregnancy week to week 37

At Week 37, you’re likely feeling huge, uncomfortable, and even exhausted with being pregnant. It’s hard to generalize, but the average woman will have gained about 30 pounds at this point. The good news is that you’re not likely to gain much more weight from here—maybe just a pound of two. The bad news is…well, you’re carrying around an extra 30 pounds.

This helps explain many of the late pregnancy symptoms you’re experiencing, including the “pregnant mom waddle” that you might have adopted recently. But it doesn’t explain all of them. In fact, your old friend progesterone, a pregnancy hormone, is still hard at work in your body, loosening up your joints and ligaments in preparation for birth. This has a lot of do with that new strange walk.

Now that you’re close, your healthcare provider will be performing regular check-ups during your weekly visits. This might include a pelvic exam, which is a simple physical examination of your cervix, the birth canal, and the baby’s position, among other things. The cervical exam is not always needed unless you are at or past your due date or complaining of labor symptoms. However, it can be important to check now because, no matter how many contractions you’re having, you’re not officially in labor until certain changes have occurred in your cervix, including:

  • Dilation. During pregnancy, your cervix is tightly shut, forming a protective barrier that allows your baby to grow in a safe environment. As labor nears, however, your cervix very slowly begins to relax and open, or dilate. Ultimately, during labor, your cervix will expand to 10 centimeters, wide enough to let your baby’s head pass through. In some women, this dilation begins before labor officially starts. Some women can walk around at 3 or 4 centimeters dilated for weeks before they are actually in labor! It’s more about the rate of change (that is, suddenly going from a closed cervix to one that is 4 centimeters open) that can tell you if you are in labor.
  • Effacement. This describes the length of your cervix. During labor, your cervix will gradually efface, or become thinner or shorter, as it stretches to allow your baby passage. Once again, effacement can begin before labor actually begins.
  • Station. This refers to how low your baby’s head is in the birth canal.

It’s important at this stage to report any changes in your condition or symptoms to your healthcare provider, including increased vaginal discharge, regular painful contractions, uneven leg swelling, or anything else that just doesn’t seem right for you. In many cases, such as passing the mucus plug that sealed your cervix shut, new symptoms are nothing to worry about. Other cases, such as bad headaches or vision changes, can signal dangerous health conditions that require treatment.

Your Baby

At 35 weeks (fetal age), your baby is still gaining weight, even if it’s slower than before. A typical baby at this stage can weigh as much as 6.5 lbs. and measure 19 inches from head to toe. This is actually very close to the final birth weight and length.

your baby pregnancy week 37

In fact, the vast majority of the developmental work is done—but there’s still a very good reason ACOG changed the definition of full term. The last major organ system to develop is the respiratory system. Specifically, the lungs don’t begin to produce surfactant until just before birth. This special lubricant helps the lungs expand smoothly as they fill with oxygen. The lack of surfactant is the major reason premature babies often experience breathing difficulty. Also, studies have shown us that babies born before 39 weeks have more complications, is the reason the new definition of “full term” does not apply until you are 39 weeks pregnant. So hang in there! Your baby shouldn’t be encouraged to make an entrance until he or she is ready, since they need that precious time to finish developing.

Otherwise, your baby looks very much like he or she will look in two short weeks. There may already be a full head of hair, and his or her fingernails and toenails are growing on their own now. It can be a strange sight to have a baby who almost immediately needs to have his or her nails trimmed!



Doctor tip
“If you go to the hospital and are sent home because you weren’t in active labor, don’t feel bad. It can sometimes be hard to know, especially with your first baby!”

Read more doctor tips.

Reviewed by Dr. Jen Lincoln, April 2020


Tell us who you are! We use your name to make your comments, emails, and notifications more personal.

Tell us who you are! We use your name to make your comments, emails, and notifications more personal.