The role of ultrasound in the management of twin pregnancies.

Abstract

ABSTRACTThe high perinatal mortality and morbidity in twin pregnancies is mainly associated with preterm labour and placental insufficiency. Early diagnosis, allowing adequate time for increased rest and aggressive treatment of threatened preterm labour, is the most important single factor in reducing this wastage.While ultrasound prior to 20 weeks of gestation is the only reliable method of achieving early diagnosis of all twin pregnancies, the safety and cost‐effectiveness of routine ultrasound has not yet been established.Based on the results from 196 twin pairs, the mean biparietal diameter (B.P.D.) for the smaller and larger twin is compared to the mean birthweight at each gestation. The decline in the B.P.D. increase appears to precede the drop in birthweight by about 2 weeks. There are sufficient false results in both directions to justify caution in interpretation of a single set of readings.Polyhydramnios and dilatation of the cervix, both associated with preterm labour, and monoamniotic twins, associated with cord entanglement at delivery, can also be diagnosed by ultrasound.