- The definition of a postterm pregnancy is when a baby is delivered after 42 weeks’ gestation.
- Somewhere between 4 and 19 percent of babies will reach or exceed 42 weeks’ gestation.
- Your provider may recommend increased monitoring and possibly an induction if you go well past your due date.
One of the most common questions many pregnant women hear is, “When are you due?” While a due date is a carefully calculated and important part of your pregnancy, it is at best an educated guess. Considering that only 5 percent of babies arrive on their due date, you might be wondering what happens if your due date comes and goes without any signs of labor.
Just last year, the American Congress of Obstetricians and Gynecologists (ACOG) redefined what a term and postterm pregnancy is. Even though your due date is when you will be exactly 40 weeks pregnant, pregnancies up to the start of 41 weeks are still considered full term. A pregnancy is only called postterm if your baby still hasn’t arrived by the start of the 42nd week.
Somewhere between 4 and 19 percent of babies will reach or exceed 42 weeks’ gestation. Women who are having their first baby or have gone past their due date before are more likely to be delivered postterm (or at the very least late term). An incorrectly calculated due date can also be a reason for being “overdue”!
The reason your provider will monitor you more closely and may recommend an induction of labor if you go past your date is to prevent certain complications that are more likely after your due date. A postterm placenta does not usually work as well, which can lead to decreased blood flow to the baby and lower levels of amniotic fluid. Risks of macrosomia (larger fetal growth), shoulder dystocia, fetal distress, abnormal labor patterns, meconium aspiration, and hemorrhage at time of delivery are all higher in postterm deliveries.
Risk for stillbirth is also another serious complication that becomes more common the longer a pregnancy progresses, with a dramatic increase after 41 weeks. For every 10,000 women, there will be 2.1 stillbirths at 37 weeks gestation, but that number rises to 10.8 by 42 weeks’ gestation.
With all of these issues in mind, your provider will likely recommend some form of monitoring if you have not delivered by your due date or shortly after. This may include an ultrasound to assess your baby’s activity and the level of amniotic fluid, as well as monitoring the baby’s heartbeat for a short period to make sure it looks normal. This is called a nonstress test.
At some point, your doctor or midwife may recommend an induction of labor. When exactly this is recommended may vary based on the details of your pregnancy, the results of your baby’s monitoring, and individual practice patterns. For the most part, many providers will recommend an induction between 41 and 42 weeks of pregnancy.
It is important to keep in mind that many women will go into spontaneous labor after their due date and their babies will have no issues. Rushing into an induction one day past your due date can lead to increased interventions and possibly a C-section, so it is important to have a thorough conversation with your obstetric provider. Even though it feels like you may be pregnant forever, fear not! You will meet your little one soon.