Induction of labor is the artificial starting of labor.
Usually, labor is induced by giving the woman oxytocin, a hormone that makes the uterus contract more frequently and more forcefully. The oxytocin given is identical to the natural oxytocin produced by the pituitary gland. It is given intravenously with an infusion pump, so that the amount of drug given can be controlled precisely. Before contractions of the uterus can be induced, the cervix must be thinned (effaced) and ready to open (dilate) so that the baby can be delivered. Sometimes prostaglandins (such as misoprostol) are used to help the cervix efface and dilate. They are given vaginally. Alternatively, a tube (catheter) with a balloon attached or dried seaweed stems (laminaria) can be inserted in the cervix. The balloon is inflated to dilate the cervix. Laminaria absorb fluids and then expand, thus dilating the cervix.
Problems that usually require induction of labor include high blood pressure with protein in the urine (preeclampsia) in the woman or signs that the fetus is not well (fetal distress).
Labor is not induced if women have had certain types of surgery involving the uterus or certain types of cesarean deliveries or have active genital herpes. It is also not done if the fetus is not in the normal position or is too large or if the placenta is in the wrong position.
Throughout induction and labor, the fetus's heart rate is monitored electronically. At first, a monitor is placed on the woman's abdomen. Occasionally, after the membranes are ruptured, an internal monitor is inserted through the vagina and attached to the fetus's scalp. If induction is unsuccessful, the baby is delivered by cesarean.
Last full review/revision June 2013 by Julie S. Moldenhauer, MD