Generally, labor begins within a week of the estimated date of delivery (EDD or 40 weeks gestation), but it is fairly common to extend further beyond the due date (the term “post-dates” refers to a pregnancy past 41 weeks). This is not a dangerous situation as long as we can be reasonably assured that the placenta is still functioning well (which is done with fetal testing, as described below).
When facing post-dates pregnancy, clients are often interested in forms of natural labor stimulation. On the next page are some things that might be helpful to get some contractions going, which may help to ready the cervix for labor, or may be used in the birth center as a means of “natural induction.”
• Sexual activity is a way to help “ripen” the cervix. Orgasm in the birthing parent makes the uterus contract. Components in semen have a softening effect on the cervix. Breast stimulation releases a labor-inducing hormone from the brain.
• Castor oil is given to stimulate the bowels, which in turn stimulates the uterus. It can be unpleasant but effective. Prior to taking castor oil, we ask that you check in with the midwife on call by paging her.
• Nipple stimulation at term releases oxytocin, which can stimulate contractions. The midwives may discuss breast pumping at The Midwife Center if indicated as pregnancy approaches 41 weeks. This is typically reserved for pregnancies over 41 weeks, but may be done sooner if indicated.
• Membrane sweeping can be done in the office. This consists of a cervical exam and if a client is 1 cm dilated, the provider may be able to “sweep” around, releasing small adhesions of the bag of waters from the uterus. This often stimulates contractions.
• A “foley bulb” or “Cooks catheter” is a means of cervical ripening for clients who, at 41 weeks, may be 1-2cm or less. This procedure is done at The Midwife Center and involves the insertion of a flexible silicone catheter into the cervix. A balloon is filled up with sterile water and the catheter is secured to the leg. The way it works is by releasing prostaglandins, (a substance which causes cramps and contractions) in addition to a manual dilation. Clients may go home with the catheter in place.
If your pregnancy does extend to 41 weeks, the midwives will discuss two options with you. One is to opt for a labor induction at the hospital, as it is medically indicated to deliver at 41 weeks. The other option is to continue pregnancy to 42 weeks with some fetal testing to ensure the placenta is working well. We know it is safe to be pregnant past 41 weeks as long as the testing is good.
The post dates testing includes:
• Non-stress test (NST) – Involves tracing the baby’s heart rate pattern on an electronic fetal monitor and looking for the baby’s heart rate to speed up when the baby moves. This is done at 41 and 41 ½ weeks.
• Biophysical Profile (BPP) – This is a sonogram that looks at the amount of amniotic fluid, the state of the placenta, breathing motions and fetal movements. This done at 41 weeks, but may be done at other times if clinically indicated. An exact measurement of the amniotic fluid is also performed.
If delivery has not occurred by 42 weeks, a medical induction of labor is recommended at the hospital. Deliveries after 42 weeks will be at UPMC Magee Hospital or West Penn.
Pregnancies very rarely continue past 42 weeks.