Drug therapy during labor and delivery.

Situations related to labor and delivery that may require drug therapy are discussed, and treatment options are reviewed. The goal of labor induction and augmentation at term is to facilitate vaginal delivery of a healthy infant. The primary uterine stimulant used for this purpose is oxytocin. Low-, intermediate-, and high-dose protocols have been reported; augmentation requires approximately half as much oxytocin as induction does. Mifepristone has also been used for labor induction. Prostaglandins are the primary agents used for cervical ripening, but oxytocin, relaxin, and mifepristone have also been used. Mechanical dilators are available for cervical dilation, which may be necessary when prostaglandins are contraindicated. Oxytocin is the drug of choice for preventing postpartum hemorrhage; if it is not effective, methylergonovine or carboprost may be used to control the hemorrhage. Labor induction during the midtrimester may be necessary because of obstetrical or medical complications or fetal death. These situations call for aggressive dosing of uterine stimulants (e.g., high-dose oxytocin, intravaginal dinoprostone suppositories, carboprost, mifepristone). Drug therapy may be required for labor induction or augmentation, cervical ripening or dilation, and prevention or control of postpartum hemorrhage. Oxytocin is the most commonly used agent for labor induction or augmentation and for prevention of postpartum hemorrhage; prostaglandins are frequently used for cervical ripening. Aggressive dosing of uterine stimulants is required when labor must be induced during the midtrimester.