Full-Term Pregnancy Explained

As you near the end of your third trimester, you're probably counting down the days until your due date. Try to keep in mind that this date is just an estimate and that only about 5 percent of babies are born exactly on time. As your pregnancy progresses, you may be wondering what exactly is considered a full-term pregnancy, and what will happen if your baby is born a little earlier — or later — than expected. It can help you feel prepared to understand what is meant by preterm, early term, full term, late term, and postterm, and how these outcomes can affect you and your baby. Read on to find out!

How Many Weeks Is a Full-Term Pregnancy?

Your baby is officially considered full term at 39 weeks. In the past, a “term” pregnancy meant that you gave birth in a five-week window around your due date — somewhere between three weeks before and two weeks after, or from the start of 37 weeks to the end of 42 weeks.

Medical experts now know that babies still have a lot of developing to do at 37 and 38 weeks, so pregnancy is now considered “full term” at 39 weeks.

Newer research shows that a baby born at 39 or 40 weeks is less likely to face developmental problems than if he were born earlier. For example, if your baby is born at 39 or 40 weeks, he'll generally have better feeding and breathing skills, be able to better control his body temperature, and may have a stronger immune system than if he were born a little earlier.

What Do Preterm, Early Term, Late Term, and Postterm Mean?

The American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine have defined the final weeks of pregnancy as follows:

  • Preterm — before 37 weeks

  • Early term — start of week 37 until the end of week 38

  • Full term — start of week 39 until the end of week 40

  • Late term — start of week 41 until the end of week 41

  • Postterm — start of week 42 onward.

In order to be more precise, your healthcare provider may sometimes divide these weeks into days, as in 38 and 6/7, for example, which means 38 weeks and 6 days pregnant.

It can be a little tricky to remember which week of pregnancy is which but this image should help make it a little easier:

terms of pregnancy

What Is Considered Full Term for a Twin Pregnancy?

Most medical professionals say that, if there are no complications in the pregnancy, twins can be delivered a little earlier, at 38 weeks.

This is because the placenta can start to become less effective at nourishing your little ones after about 38 weeks. Keep in mind, if yours is a twin pregnancy, your provider will be keeping a close eye on you and your twins and will be able to determine whether it's best to wait until your pregnancy is full term and you go into labor naturally, or whether it's better to deliver your babies a little earlier via cesarean section or by inducing labor.

Is 37 Weeks Full Term?

The idea that 37 weeks is full term has been updated in recent years. Healthcare providers now know more about how important 37 and 38 weeks are for your baby's development. In some cases, such as if there is a health risk to you or your baby (for example, a condition called placenta previa), your healthcare provider may say it's necessary for you to give birth before 39 weeks.

Are There Risks if Your Baby Is Overdue?

It's normal for your baby to arrive a little earlier or later than your due date. Your due date is, after all, only an estimate of when your pregnancy will have lasted 40 weeks. Once you've reached your due date, there's still two more weeks to go before your pregnancy is considered postterm. This is why your provider may just recommend being patient for a few more days or weeks if your due date comes and goes with no sign that your little one's ready to make a move.

When assessing the best course of action for your personal situation, there are a few risks your provider will be keeping in mind. For example, late or postterm delivery can increase the chance of the following:

  • your baby having a higher birth weight

  • you having a longer labor

  • you needing an operative vaginal delivery, in which forceps or a special suction cup may be used to help deliver the baby

  • you needing a cesarean section

  • you having some perineal tearing.

To check that everything is OK with your little one, your healthcare provider may perform special tests like a nonstress test to measure your baby's heart rate or an ultrasound to check on the amniotic fluid. Your provider will also be checking your baby's position, size, and movements. If everything is looking good, your provider may recommend delaying induction for a couple more days or weeks.

When Might Labor Be Induced?

If your due date has come and gone, in some cases your healthcare provider might recommend that labor be induced. This step might be taken to reduce the risk of possible complications, such as your baby being significantly bigger at birth or there being lower amounts of amniotic fluid.

Keep in mind, labor can sometimes be induced earlier in pregnancy, too. Induction is sometimes considered during the full- or preterm stage if you have health complications like gestational diabetes or high blood pressure; if there are problems with the placenta like placental abruption (when the placenta separates from the uterus); or if your baby shows signs of poor growth.

You'll have a lot on your mind toward the end of your pregnancy, so remember that your healthcare provider is on top of this, and she will give you all the information you need before any decisions are made about inducing labor. You're in good hands!

Can You Reduce the Chance of a Late or Postterm Pregnancy?

There's no surefire way to prevent a late- or postterm pregnancy. However, you are more likely to go past your due date if

  • you are pregnant with your first child

  • you've had a late- or postterm pregnancy before

  • you are obese.

In some cases, to keep your pregnancy from progressing to the late- or postterm stage, your provider may recommend something called stripping membranes. In this procedure, your provider will “sweep” a gloved finger along the membranes that connect the amniotic sac to your uterine wall. This can sometimes help to soften the cervix and kick-start contractions.

If you just can't wait to give birth, you may be starting to wonder about the effectiveness of some old wives' tales like castor oil being used to begin labor. Keep in mind, there's not enough medical evidence to support the safety and effectiveness of castor oil, so if you're considering alternative ways to jump-start labor, check with your healthcare provider first.

Is an Elective Delivery an Option?

In consultation with their healthcare providers, some moms-to-be end up having a scheduled cesarean section delivery or an induction. There are a variety of nonmedical reasons an elective delivery could be considered, including living in a rural area far away from the hospital; reducing end-of-pregnancy discomfort; or easing childbirth anxiety or fear. If you're interested in an elective delivery, ask your healthcare provider whether this may be a safe option for you and your baby.

It might feel as if you've been waiting forever to meet your baby, but your little one will be here before you know it. Make sure you're aware of those telltale signs of labor and how to time your contractions so you'll know when it's time to call your healthcare provider.

While you wait for the big day, don't forget to download the Pampers Rewards app to start earning rewards and discounts on all those baby products you'll need.

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