Inducing labor when your baby is overdue

Nobody can predict the exact day on which you will give birth. Most babies are born in the two weeks before or after the due date. Because of this, doctors and midwives often use the term “due date range” instead of just “due date.” But it’s still important to narrow the date down as much as possible. This is because prenatal check-ups and maternity leave are planned based on the due date. And the due date is also used to decide whether and when to recommend inducing the birth.

A pregnancy is considered to last about 40 weeks. The estimated due date is calculated from the first day of the woman’s last period. Not every woman can remember exactly when that was, though. And some women still have light bleeding at the start of their pregnancy, around the time when they would normally have got their period. So they might actually have become pregnant several weeks before they thought they did. On top of that, some women's eggs aren't always released exactly two weeks after their last period. If the egg was only released three weeks after, for example, then the pregnancy started later than estimated. Many women actually feel when the egg is released (ovulation), so they can say exactly when they became pregnant.

Your gynecologist will also do an ultrasound scan to see whether the due date calculated based on your last period is about right. They can determine the age of the embryo quite accurately during the first few weeks of the pregnancy based on the crown-rump length (the length of the embryo). But this isn’t 100% accurate either.

It is usually not possible to say why some pregnancies last a little longer than others. Sometimes it's because of the woman's genes. Women who've already had a clearly overdue baby are more likely to have an overdue baby next time too.

If the mother-to-be and her baby are both doing well when the due date comes around, it’s possible to wait for the birth to start naturally. But if the pregnancy lasts much longer, there’s a slightly higher risk of health problems, especially for the child. It is more common for these babies to need intensive care when they’re born. The risk of the baby dying also increases slightly as time goes on. This risk is even higher once the 43^rd week of pregnancy begins. But it’s very rare for a pregnancy to last that long because labor is usually induced by then, to avoid those risks.

One possible reason for the risks linked to longer pregnancies is that the mother’s placenta can no longer supply the child with everything it needs. So regular check-ups are done once the due date has passed, to see whether the placenta is still working properly.

When a baby is past its due date, it’s important to keep an eye on the mother and the child. The recommendation in Germany is around two check-ups per week. These are usually done at your gynecologist’s practice, but sometimes they’re done in the hospital instead. The check-ups may include monitoring the baby with cardiotocography (CTG – also called electronic fetal monitoring or a non-stress test) and an ultrasound scan. The CTG monitors the baby’s heartbeat. The ultrasound scan is used to check the baby’s size and the amount of amniotic fluid around the baby. If the baby is growing slowly or there isn’t enough amniotic fluid, it could be a sign that the placenta isn’t supplying the baby properly.

If your baby is past its due date, you can talk to your childbirth team and people close to you and decide together whether the birth should be induced – and if so, when. Your age and the baby’s estimated weight may influence the decision.

At the beginning of the second week after your due date (when you enter the 42^nd week of pregnancy, from 41+0 onwards), your doctor or midwife will usually suggest that the labor is induced. They often check the due date again first.

At the beginning of the third week after the due date (the 43^rd week of pregnancy, starting on 42+0), your childbirth team will recommend inducing labor as soon as possible.

Researchers compared two groups of women whose births were induced at different points of their pregnancy:

• Beginning of the second week after the due date (42^nd week of pregnancy)
• Beginning of the third week after the due date (43^rd week of pregnancy) if labor had not started on its own by then

The researchers found the following differences:

Both groups of women had the same amount of severe perineal tears (between the vagina and anus). And instruments that are used to help the birth along, like ventouse suction cups, were used just as often for women who had an induction as for those who didn’t.

Even when the due date hasn’t passed and the birth wasn't induced, complications can occur and a C-section or neonatal intensive care may be needed.

Side effects can vary, depending on how the labor is induced. Medication is often used. This can cause things like nausea and vomiting. Sometimes the induction affects the womb too much (hyperstimulation). When this happens, the contractions are particularly strong and the gaps between them are very short. That can be very painful for the woman and cause problems for the unborn child, such as not getting enough oxygen. Then the woman might need more medication to slow the contractions back down and relieve the pain.

Induced births tend to involve more vaginal examinations than non-induced births do. Many women find these unpleasant.

Doctors and midwives usually do not recommend inducing labor before the start of the 42^nd week. But if you really want your labor to be induced earlier, doctors may consider doing if from the 40^th week onward. In other words, the week of your due date. Inducing labor before the 40^th week is only an option if there are medical reasons to do so. For instance, if your water breaks too early or if you have pre-eclampsia.

Research has shown that the pros and cons of inducing labor were similar, no matter whether it was done in the 40^th, 41^st or beginning of the 42^nd week: The babies were similarly healthy. The amount of instrument-assisted deliveries (vacuum deliveries, for example) was similar in all cases. And severe perineal tears were equally common.

There was one difference, though: The need for a C-section was slightly lower when labor was induced earlier: C-sections were needed in

• 110 out of 1,000 births that were induced in the 40^th week, and
• 120 out of 1,000 births that were induced after waiting until the 42^nd week.