Ultrasound evaluation of the postdate pregnancy.

In summary, ultrasound plays an important role in the evaluation of the postterm pregnancy, and its use should be considered in the following situations: 1) estimation of fetal weight in the potentially macrosomic infant before vaginal delivery is attempted; 2) frequent evaluation for oligohydramnios using the amniotic fluid index for the expectant management of the postdate pregnancy; 3) placental evaluation prior to elective induction of labor in a poorly dated pregnancy; and 4) evaluation of the postterm fetus for possible congenital abnormalities.