title: Sonar cephalometry in twin pregnancy: discordancy of the biparietal diameter after 28 weeks' gestation.
abstract: Sonar measured biparietal diameter (BPD) differences of twin paires were examined in 123 twin pregnancies at or beyond 28 weeks' gestation. Among 117 liveborn sets, the risk of a twin infant being small for gestational age was threefold greater when paired BPD differences were 5 mm or more compared to 4 mm or less. The incidence of fetal death increased from 2.7% for twin pairs with 0 to 6 mm BPD differences to 20% when the difference was 7 mm or more. Sonar cephalometry may be helpful in the antepartum evaluation of twin pregnancies, although detection of BPD discordancy does not preclude normal twin outcome.
mesh_terms: D000328:Adult; D001724:Birth Weight; D002508:Cephalometry / Q000379:methods*; D005260:Female; D005313:Fetal Death; D005317:Fetal Growth Retardation / Q000209:etiology; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011272:Pregnancy, Multiple; D012306:Risk; D014427:Twins; D014463:Ultrasonography