Overdue pregnancy: What to do when baby’s overdue

Your due date has come and gone — and you’re still pregnant. What’s going on?

Although your due date might seem to have magical qualities, it’s simply an estimate of when your pregnancy will hit 40 weeks. The due date does not calculate when your baby will arrive. It’s common to give birth before or after a due date. In fact, pregnancy is only considered to be “postterm” when it is two weeks past a due date.

You might be more likely to have a postterm pregnancy if:

• This is your first pregnancy.
• You’ve gone two weeks past your due date in a previous pregnancy.
• Your baby is a boy.
• You have a body mass index of 30 or higher (obesity).
• Your due date was calculated incorrectly. This could be due to confusion over the date of the start of your last menstrual period. It can also happen when the date is calculated based on an ultrasound that’s done after 22 weeks of pregnancy.

Genetics also may play a role in some cases. Rarely, an overdue pregnancy might be related to problems with the placenta or the baby.

Whatever the cause, you’re probably tired of being pregnant, and you might be feeling more anxious as the days go by. Fortunately, an overdue pregnancy won’t last forever. Labor could begin at any time.

Between 41 weeks and 41 weeks and six days, a pregnancy is called late-term. When a pregnancy reaches 42 weeks and beyond, it’s postterm. Late-term and postterm pregnancy can raise the risk of some health problems, including:

• Larger than average birth size (fetal macrosomia). This increases the chance that you may need forceps, a vacuum device or another instrument to assist with the birth. It may raise the risk of requiring a C-section. A larger baby is more likely to get a shoulder stuck behind your pelvic bone during delivery (shoulder dystocia)
• Postmaturity syndrome. This condition is marked by decreased fat beneath the baby’s skin; a lack of a greasy coating (vernix caseosa); decreased soft, downy hair (lanugo); and staining of the amniotic fluid, skin and umbilical cord by the baby’s first bowel movement (meconium)
• Low amniotic fluid (oligohydramnios). This can affect the baby’s heart rate and compress the umbilical cord during contractions

Late-term and postterm pregnancies can cause problems related to delivery. Some mothers may experience:

• Severe vaginal tears
• Infection
• Postpartum bleeding

When you’re more than one week past your due date, your health care provider might do a test that measures the baby’s heart rate (nonstress test). That test may be combined with an ultrasound exam to check the baby’s heart rate, breathing, muscle tone and movement (biophysical profile). The amniotic fluid usually is checked too.

Based on these tests, your health care provider may recommend labor induction. Labor induction starts uterine contractions before labor begins on its own.

Your health care provider may suggest ways to help get labor started, such as:

• Ripening the cervix. You might be given medicine to soften and expand (ripen) your cervix. Or your health care provider might ripen your cervix by inserting into it a small tube (catheter) with an inflatable balloon on the end.
• Sweeping the membranes of the amniotic sac. With this technique, also known as stripping the membranes, the health care provider sweeps a gloved finger over the covering of the amniotic sac near the fetus. This separates the sac from the cervix and the lower uterine wall.
• Rupturing the amniotic sac. If your amniotic sac is still intact, your health care provider might release the fluid in it by creating an opening with a thin plastic hook. The opening causes the water to break.
• Using medication to start contractions. A version of oxytocin (Pitocin), a hormone that causes the uterus to contract, may be taken to trigger labor.

Typically, ripening the cervix, rupturing the amniotic sac and using Pitocin to start contractions are done at a hospital in the labor and delivery unit.

Whether you take a wait-and-see approach or schedule an induction, stay in touch with your health care provider. Make sure you know what to do if you think you’re in labor. In the meantime, do your best to enjoy the rest of your pregnancy.