A pregnancy usually lasts for 38 to 42 weeks. It is considered overdue if it lasts more than 42 weeks. “Post-term pregnancy,” “prolonged pregnancy” and “post-date pregnancy” are other phrases used to describe a pregnancy that lasts more than 42 weeks.
How is my due date determined?
One way to estimate your due date is to count 40 weeks ahead from the first day of your last menstrual period. However, some women can’t remember the first day of their last period or are not exactly sure when they got pregnant. It can be especially hard to estimate an accurate due date if you get pregnant soon after you stop taking birth control pills. An ultrasound (also called a sonogram) that is done early in your pregnancy can give your doctor information to help him or her estimate your due date.
What if my pregnancy goes past the due date?
If your pregnancy lasts 1 week past your estimated due date, your doctor will probably begin checking your baby more closely. Your doctor may use an electronic fetal monitor to check how your baby’s movements affect his or her heart rate. This is called a nonstress test. In addition, your doctor may do an ultrasound to look at how much amniotic fluid is around your baby. Ultrasound can also be used to check your baby’s position and to see how much he or she is moving. (You should continue to feel your baby move throughout your pregnancy. If you feel less movement, call your doctor.)
Toward the end of pregnancy, the cervix (the opening to the uterus) gets soft. It may even open up a little (also called dilation). If you are past your due date, your doctor may begin checking to see if your cervix is getting soft and opening up.
Depending on how you and your baby are doing, your doctor may recommend using certain medicines or other methods to induce (start) labor. This is done to avoid complications (for example, a baby growing so large that he or she would be hard to deliver vaginally) or fetal distress. Fetal distress happens when the baby doesn’t get enough oxygen. This causes the baby’s heart rate to drop, and the baby can’t tolerate the stress of labor. Many doctors will induce labor if a woman is 2 weeks past her due date.
How will my doctor induce labor?
There are several ways your doctor may induce labor, including the following:
- Use medicine or a special device to help your cervix get soft and open up.
- “Break your water” by making a small opening in the sac filled with amniotic fluid. This is not painful, but you may feel fluid leak out when the amniotic sac is broken.
- Use a gloved finger to separate the amniotic sac from the wall of your uterus. This is called “sweeping the membranes” or “stripping the membranes.” It can feel uncomfortable and cause cramping or spotting. This method releases hormones that may make labor start for some women.
- Give you a medicine called oxytocin (brand name: Pitocin). It will start your contractions and help them get strong and regular. Oxytocin is given intravenously (through an IV needle into your vein). It usually starts to work in 1 to 2 hours.
Can I start labor myself?
You may have heard about ways to start labor yourself (for example, having sex, eating spicy food, taking a long walk). There is no scientific evidence that these methods work, and some of them can cause problems. To keep yourself and your baby safe, check with your doctor before you do anything to try to induce labor on your own.
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.