Why at least 39 weeks is best for your baby

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Key Points

If your pregnancy is healthy, it’s best to stay pregnant for at least 39 weeks. Wait for labor to begin on its own.

Scheduling means you and your provider decide when to have your baby by labor induction or cesarean birth.

If your provider recommends scheduling your baby’s birth, ask if you can wait until at least 39 weeks so your baby has time to fully develop.

Your baby’s brain, lungs, liver and other important organs are still developing in the last weeks of pregnancy.

Babies born too early may have more health problems at birth and later in life than babies born later.

Are you thinking about scheduling your baby’s birth? 

Scheduling your baby’s birth means you and your health care provider decide when to have your baby by labor induction or cesarean birth instead of waiting for labor to begin on its own. Depending on your health and your baby’s health, scheduling your baby’s birth may be best. But scheduling birth a little early for non-medical reasons can cause problems for you and baby. If your pregnancy is healthy, it’s best to stay pregnant for at least 39 weeks and wait for labor to begin on its own.

When you schedule your baby’s birth, you schedule either labor induction or a c-section. Labor induction (also called inducing labor) is when your provider gives you medicine or breaks your water (also called amniotic sac) to make your labor begin for vaginal birth. Vaginal birth is when the muscles of your uterus contract (get tight and then relax) to help push your baby out through the vagina (also called birth canal). Most babies are born by vaginal birth. A cesarean birth (also called c-section) is surgery in which your baby is born through a cut that your provider makes in your belly and uterus.

You may not have a choice about when to have your baby. If there are problems with your pregnancy or your baby's health, you may need to have your baby early. But if you have a choice and you're planning to schedule your baby's birth, wait until at least 39 weeks.

Why does your baby need 39 weeks?

Babies born too early may have more health problems at birth and later in life than babies born later. Being pregnant 39 weeks gives your baby's body all the time it needs to develop.

Your baby needs 39 weeks in the womb because:

  • Important organs, like your baby’s brain, lungs and liver, need time to develop. The brain develops fastest at the end of pregnancy. A baby’s brain at 35 weeks of pregnancy weighs only two-thirds of what it will weigh at 39 to 40 weeks. 
  • He’s less likely to have health problems after birth, like breathing, vision and hearing problems.
  • He can gain more weight in the womb. Babies born at a healthy weight have an easier time staying warm than babies born too small.
  • He can suck and swallow and stay awake long enough to eat after he's born. Babies born early sometimes can't do these things.
  • He’s less likely to have learning problems and health problems later in life than babies born before 39 weeks.

Can scheduling an early birth cause problems for you and your baby?

Yes. Sometimes it's hard to know exactly when you got pregnant. Even with an ultrasound, your due date can be off by as much as 2 weeks. If you schedule an induction or c-section and your date is off by a week or 2, your baby may be born too early. Ultrasound uses sound waves and a computer screen to show a picture of your baby inside the womb.

Problems from inducing labor

  • Stronger and more frequent contractions. Frequent contractions may cause changes in your baby’s heart rate.
  • Infection for you and your baby
  • Uterine rupture. This is when the uterus tears during labor. It happens very rarely.
  • Needing a c-section. If your labor is induced and the medicine doesn’t start your labor, you may need to have a c-section.

Problems from a c-section

  • Breathing and other medical problems for your baby. Babies born by c-section may have more breathing and other medical problems than babies born by vaginal birth.
  • Needing a c-section in another pregnancy. Once you have a c-section, you may be more likely in future pregnancies to have a c-section. The more c-sections you have, the more problems you and your baby may have, including problems with the placenta.
  • Longer recovery for mom. A c-section is major surgery. It takes longer for you to recover from a c-section than from a vaginal birth. You can expect to spend 2 to 4 days in the hospital after a c-section. Then you need about 6 to 8 weeks after you go home to fully recover. You also may have complications from the surgery, like infections, bleeding or blood clots.  So it's important to stay in touch with your health care provider even after you go home.

What questions can you ask your health care provider about scheduling your baby's birth?

If you’re planning to schedule your baby’s birth, print out this article and take it with you to your next prenatal care checkup. Ask these questions:

If your provider recommends that you have your baby before 39 weeks

  • Is there a problem with my health or the health of my baby that makes birth before 39 weeks necessary?  
  • Can I wait to have my baby until I’m closer to 39 weeks?

About inducing labor

  • Why do you need to induce labor?
  • How will you induce my labor?
  • What can I expect when you induce labor?
  • Will inducing labor increase the chance that I’ll need to have a c-section?

About having a c-section

  • Why do I need to have a c-section?
  • What can I expect during and after a c-section?
  • What problems can a c-section cause for me and my baby?
  • Can I have a vaginal birth in future pregnancies?

See also:  39 weeks infographic

Last reviewed: October, 2018