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Most babies arrive more or less on schedule. But (surprise!) some little ones may show up too early. And these early arrivals need more care. It's important for moms-to-be to know the signs of preterm labor.

What's preterm labor?

Wondering what counts as preterm labor and what's full-term? Here's a breakdown:

• Preterm: Labor begins before week 37.
• Early-term: Labor begins during weeks 37 or 38.
• Full-term: Labor begins during weeks 39 or 40, or within the next six days.

It's best for babies to be carried until they are full-term. That's because their little bodies and organs aren't quite finished growing. Babies born preterm are at risk for serious and even life-threatening health issues, as well as other problems that may affect them later in life, like learning disabilities. But even babies born early term may have more health problems than a full-term baby.

What causes preterm labor?

No one really knows for sure. We do know that certain things may increase your risk for preterm labor. Some of these include:

• Having had a preterm birth before.
• Having certain problems with your uterus or cervix (such as a short cervix).
• Being pregnant with twins, triplets or more babies.
• Smoking or substance abuse.
• Not receiving regular prenatal care.

Other factors can also increase your risk for preterm labor. If you have questions about your risk, ask your provider.

What should you watch for?

Remember, the signs and symptoms of preterm labor occur before the 37th week of pregnancy and, according to the March of Dimes, may include:

• An unusual fluid discharge from your vagina—it may contain water, mucus or blood.
• Pressure in your lower belly or pelvis—it may feel like the baby is pushing.
• A constant low, dull backache.
• Mild belly cramps (with or without diarrhea).
• Regular or frequent contractions (which may not even hurt!) that make your belly tighten like a fist.
• Your water breaks—there may be a gush or a trickle of fluid.

If you suspect preterm labor, call your provider right away

Your provider may run some tests to find out for sure whether you're actually in labor. For instance, you may have an ultrasound exam to see if your cervix is starting to thin out and dilate.

But even if you are in preterm labor, it doesn't necessarily mean your baby will arrive early. In fact, only about 10% of women who go into preterm labor give birth within the next seven days. It's possible that your provider may give you medicine to delay your delivery so your little one has more time to grow.

Also, about 30% of the time, preterm labor just stops on its own, according to the American College of Obstetricians and Gynecologists. That being said, it's still always best to reach out to your provider if you think you're having preterm labor.

What to do about labor and delivery pain

Concerned about natural childbirth pains? Learn about your options for managing labor pains.

Additional source: Eunice Kennedy Shriver National Institute of Child Health and Human Development

Reviewed 1/11/2024