Duplex Doppler ultrasound in the evaluation of growth in twin pregnancies.

Fifty-six multiple pregnancies were evaluated for evidence of discordant growth using traditional ultrasonic methods and duplex Doppler ultrasound. The pregnancies consisted of 52 sets of twins and four sets of triplets. Duplex Doppler ultrasound predicted normal growth in 44 of 45 normal sets of fetuses, and correctly predicted discordant growth in nine of 11 discordant sets of twins. Among those nine abnormal sets, Doppler ultrasound predicted that six would become discordant before this was recognized by traditional ultrasonic measurements. Duplex Doppler ultrasound is useful in predicting and confirming concordant and discordant growth, and defining the cause of fetal discordancy.