Routine fetal maturity estimation by ultrasound.
The accuracy of ultrasonic estimation of fetal maturity and, therefore, the delivery date is greatest when the biparietal diameteris less than 5.0 cm and least when it is greater than 9.0 cm. A comparison of the accuracy of ultrasonic and last menstrual period based estimations of the delivery date revealed that there is no significant increase in accuracy for ultrasonic estimations when the biparietal diameter is less than 9.0 cm, but when the diameter is greater than 9.0 cm the accuracy of delivery date estimation is significantly less than that based on the last menstrual period. In pregnancies complicated by uncertain dates, recent hormonal contraception, bleeding in early pregnancy, or an irregular or prolonged menstrual cycle, ultrasound is significantly more accurate in predicting the delivery date. Ultrasonic examination for fetal maturity is indicated only when there are clinical indications such as uncertain dates for some reason or when there is fundal height discrepancy.
D036861:Delivery, Obstetric; D005260:Female; D005333:Fetus / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008598:Menstruation; D011247:Pregnancy; D013997:Time Factors; D014463:Ultrasonography