What is Full-Term Pregnancy?

How Long Pregnancy Lasts and Why Reaching Full Term Is Best

Nine months seems like an eternity when you're waiting to hold that sweet little ninja in your arms instead of feeling her kicks from inside. But waiting until your baby is full term is important for her development. Understanding what full term means and why it gives your baby a better start to life makes it a little easier to survive those last few weeks of pregnancy.

What Is Considered Full Term?

Asian mother with newborn baby in the hospital

When Do You Start Showing?

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Full term refers to a pregnancy that lasts the full normal length. Doctors consider 40 weeks as the normal length of pregnancy. The 40-week timer starts on the first day of your last period and goes until your due date, which is the estimate of when you should have your baby.

Since many women don't have their babies on their due date, doctors assign a range to what is considered full term. The commonly accepted range was 37 to 42 weeks, which gave a five-week window. Doctors thought this was a safe range with most of baby's development done.

Research now shows that babies born before 39 weeks may have a higher risk for health issues. Many experts now consider full term to mean a pregnancy that lasts from 39 weeks to under 41 weeks. Babies born between 37 weeks and 39 weeks are called early term. A pregnancy lasting from 41 weeks to 42 weeks is late term, and babies born after 42 weeks are called postterm.

If you're scheduling an induction or cesarean, experts recommend waiting until at least 39 weeks to give your baby the best chance of avoiding complications. Waiting means your baby is full term, which gives your little one the time necessary to fully develop.

Why Is Full-Term Pregnancy Important?

When you reach full-term pregnancy, your baby is considered ready to be born with a good chance of being healthy and fully developed. Babies born earlier have a higher risk of health problems. Even though your baby looks fully developed a few weeks earlier, he still has maturing to do in those last few weeks. Organs like the lungs and brain still develop toward the end of pregnancy, so it makes sense to let your baby mature as much as possible before being born.

Some of the benefits of longer gestation include:

  • Decreased risk of hearing and vision problems
  • Healthier birth weight
  • Ability to suck and swallow well
  • Mature organs
  • Lower risk of ending up in the neonatal intensive care unit
  • Fewer respiratory problems

What Happens With Baby in the Last Few Weeks

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When Does The Baby Drop?

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Doctors previously thought babies put on weight primarily from 37 weeks on with most major organ development done by that time. Research now shows that organs still develop in those last few weeks.

What happens in those major organs? Up to 39 weeks, your baby goes through the following development:

  • Surfactant develops at an increasing rate for the final month of pregnancy. This compound helps your baby breathe on her own after birth.
  • The liver develops enough to filter toxins effectively, which helps remove things like bilirubin from the body. High levels of bilirubin can cause jaundice. A baby born after 39 weeks may have fewer problems dealing with jaundice.
  • Brain and nerve connections support sucking, swallowing, breathing and temperature regulation. Those connections benefit from a longer period of development.
  • Thickening skin and body fat developed in the last few weeks support your baby in maintaining her body temperature on her own.

What Happens With You in the Last Few Weeks

The third trimester comes with some discomfort for you because of the size of your baby and belly. You may find it difficult to move around and do your normal activities because of the belly. Some women experience backaches due to pressure on the back. All of this discomfort can prompt hope for an early delivery, but enduring those last few weeks gives your baby a healthier start.

Your ligaments in your pelvic area start to loosen, so your body is ready for labor and delivery. That loosening can cause some discomfort in your pelvis and hips, but it's a sign that your body is preparing for the big day.

Your body also works to prep your uterus for labor with practice contractions called Braxton Hicks contractions. They're usually mild compared to the real thing, and they typically don't increase in intensity.

Before you go into labor, your cervix starts dilating. Expect your doctor to check your cervix at your appointments in those last few weeks. As the cervix dilates, you may notice a thick discharge called the mucus plug.

When to Call Your Doctor

You and baby go through many changes in the last few weeks until you reach full-term pregnancy. You'll likely see your doctor every week in the final few weeks of pregnancy, so you have plenty of opportunities to ask questions. Many symptoms are normal, but some are worth mentioning to your doctor. Identifying potential issues early can help you continue your pregnancy until you're full term, or minimize the effects if your baby is born early.

Call your doctor if you experience the following symptoms:

  • Intense contractions that increase in severity, or severe abdominal pain
  • Bleeding
  • Heavy discharge that soaks through a panty liner
  • Water breaking
  • Burning or pain when you go to the bathroom
  • Sudden onset of swelling, which is sometimes caused by preeclampsia
  • Severe nausea or vomiting
  • Excessive dizziness