Serial Third-Trimester Ultrasonography Compared With Routine Care in Uncomplicated Pregnancies: A Randomized Controlled Trial.

Objective: Among uncomplicated pregnancies, serial third-trimester ultrasound examinations identified significantly more cases with a composite of fetal growth or amniotic fluid abnormalities (27%) than did routine fundal height measurements (8%).

Methods: Women without complications between 24 0/7 and 30 6/7 weeks of gestation were randomized (NCT0270299) to either routine care (control arm) or ultrasound examination every 4 weeks (intervention arm). The primary outcome was a composite of abnormalities of fluid volume and growth: oligohydramnios or polyhydramnios; fetal growth restriction; or large for gestational age.