Normal full-term pregnancy lasts from 38 to 42 weeks. The “due date” or “estimated date ofdelivery” (EDD) is calculated to be 40 weeks from the first day of the last menstrual period (LMP), presum- ing regular, 28-day cycles, and without recent, prior use of oral contraceptives. Postterm pregnancyis a pregnancy thatpersists beyond 42 completed weeks of gestation. This conditionoccurs in approximately 10% of pregnancies and carries with it an increased risk of adverse outcome. The increased morbidity and mortality in a small percentage of cases, however, warrants careful evaluation of all postterm preg-nancies. In addition, postterm pregnancies can create sig-nificant stress for the patient, her family, and those caring for her. Therefore, the physician should understand the condition and the options for management.
“Postdates” is a commonly used, but misleading synonym, and should be avoided.