Elective Induction of Labor
A potential risk of elective induction is that it may be undertaken before the uterus and cervix are ready for labor. Although the trigger that causes the onset of human labor is unknown, much is known about uterine and cervical physiology in late pregnancy. Gap junction formation increases, and so does the number of oxytocin receptors in the myometrium. The cervical ground substance changes and collagen fibers are dispersed. Attempted induction before these uterine and cervical changes have occurred may lead to ineffective and long labor and may necessitate operative vaginal delivery or cesarean delivery. Depending on the maturity of the fetus, the neonate may suffer consequences related to its delivery from the uterus earlier than nature would have accomplished.
I will first review two articles by Edward Bishop. 1,2 Although these publications are several decades old, Bishop made important observations and suggestions that are pertinent to elective induction today. Subsequent information that may cause us to modify Bishop’s suggestions will be reviewed and published trials of induction of labor will be evaluated to help us decide for whom elective induction of labor is a reasonable option. Finally, the more difficult issue of the “softly indicated” induction of labor will be addressed.