Induction of Labor at 39 Weeks
Frequently Asked Questions: Labor, Delivery, and Postpartum Care
Labor induction is the use of medications or other methods to start (induce) labor.
Labor is induced to start contractions of the uterus for a vaginal birth. Labor induction may be recommended when there are concerns about the health of the woman or the fetus. It also may be recommended when labor has not started on its own.
Yes. In addition to some conditions for which labor induction is recommended, new research suggests that induction for healthy women at 39 weeks in their first full-term pregnancies may reduce the risk of cesarean birth.
Cesarean delivery is surgery and comes with certain risks, including
- bleeding, infection, and injury to the bowel or bladder
- longer recovery time than vaginal delivery
Cesarean delivery also increases risks for future pregnancies, including placenta problems, rupture of the uterus, and hysterectomy.
You and your obstetrician–gynecologist (ob-gyn) or other health care professional may talk about induction at 39 weeks if
- this is your first full-term pregnancy
- you are carrying only one fetus
- you and your fetus are healthy
When a woman and her fetus are healthy, induction should not be done before 39 weeks. Babies born at or after 39 weeks have the best chance at healthy outcomes compared with babies born before 39 weeks. When the health of a woman or her fetus is at risk, induction before 39 weeks may be recommended.
Your hospital may offer induction at 39 weeks if it has the staff and resources to do so. If your hospital offers this option, your ob-gyn or other health care professional will coordinate your care with hospital staff.
You might consider induction at 39 weeks to reduce the risk of certain health problems. Healthy women whose labor is induced at 39 weeks may have lower rates of preeclampsia and gestational hypertension than women who do not have induction at 39 weeks.
There are several methods to start labor if it has not started naturally. The ways to start labor may include the following:
- Ripening the cervix
- Stripping the membranes
- Rupturing the amniotic sac
Ripening the cervix is a procedure that helps the cervix soften and thin out so that it will dilate (open) during labor. Before inducing labor, your ob-gyn or other health care professional may check to see if your cervix is ready using the Bishop score. With this scoring system, a number ranging from 0 to 13 is given to rate the condition of the cervix. A score of 6 or less means that your cervix is not yet ready for labor. If the cervix is not ready, ripening may be done.
Ripening of the cervix may be done in the following ways:
- Using medications that contain prostaglandins. These drugs can be inserted into the vagina or taken by mouth.
- Using a thin tube that has an inflatable balloon on the end. The tube is inserted into the cervix and then expanded. This helps widen the cervix.
To “strip the membranes,” your ob-gyn or other health care professional sweeps a gloved finger over the thin membranes that connect the amniotic sac to the wall of your uterus. This also is called “sweeping the membranes.” This action is done when the cervix is partially dilated. It may cause your body to release natural prostaglandins, which soften the cervix further and may cause contractions.
Oxytocin is a hormone that causes contractions of the uterus. It can be used to start labor or to speed up labor that began on its own. Contractions usually start about 30 minutes after oxytocin is given.
To rupture the amniotic sac, an ob-gyn or other health care professional makes a small hole in the sac with a special tool. This procedure, called an amniotomy, may be done after a woman has been given oxytocin. Amniotomy is done to start labor when the cervix is dilated and thinned and the fetus’s head has moved down into the pelvis. Most women go into labor within hours after the amniotic sac breaks (their “water breaks”).
With some induction methods, the uterus can be overstimulated, causing it to contract too often. Too many contractions may lead to changes in the fetal heart rate. Other risks of cervical ripening and labor induction can include infection in the woman or her fetus.
Sometimes labor induction does not work. Early labor is the time when a woman’s contractions start and her cervix begins to open. Women who have induction at 39 weeks should be allowed up to 24 hours or longer for the early phase of labor. They also should be given oxytocin at least 12–18 hours after stripping of the membranes. If a woman’s labor does not progress, it may be considered a failed attempt at induction.
If your labor does not progress, and if you and your fetus are doing well after attempting induction, you may be sent home. You can schedule another appointment to try induction again. If your labor starts, you should go back to the hospital. If you or your fetus are not doing well after attempting induction, a cesarean delivery may be needed.
Amniotic Sac: Fluid-filled sac in a woman’s uterus. The fetus develops in this sac.
Amniotomy: Artificial rupture (bursting) of the amniotic sac.
Cervix: The lower, narrow end of the uterus at the top of the vagina.
Cesarean Birth: Birth of a fetus from the uterus through an incision made in the woman’s abdomen.
Fetus: The stage of human development beyond 8 completed weeks after fertilization.
Gestational Hypertension: High blood pressure that is diagnosed after 20 weeks of pregnancy.
Hysterectomy: Surgery to remove the uterus.
Obstetrician–Gynecologist (Ob-Gyn): A doctor with special training and education in women’s health.
Oxytocin: A hormone made in the body that can cause contractions of the uterus and release of milk from the breast.
Placenta: An organ that provides nutrients to and takes waste away from the fetus.
Preeclampsia: A disorder that can occur during pregnancy or after childbirth in which there is high blood pressure and other signs of organ injury. These signs include an abnormal amount of protein in the urine, a low number of platelets, abnormal kidney or liver function, pain over the upper abdomen, fluid in the lungs, or a severe headache or changes in vision.
Prostaglandins: Chemicals that are made by the body that have many effects, including causing the muscles of the uterus to contract, usually causing cramps.
Uterus: A muscular organ in the female pelvis. During pregnancy, this organ holds and nourishes the fetus.
If you have further questions, contact your obstetrician–gynecologist.
FAQ507. Copyright September 2018 by the American College of Obstetricians and Gynecologists
This information is designed as an educational aid to patients and sets forth current information and opinions related to women’s health. It is not intended as a statement of the standard of care, nor does it comprise all proper treatments or methods of care. It is not a substitute for a treating clinician’s independent professional judgment. Read ACOG’s complete disclaimer.