GROWTH DISCORDANCY IN TWIN PREGNANCIES - A RISK FACTOR NOT DETECTED BY MEASUREMENTS OF BIPARIETAL DIAMETER

  • 1 January 1985
    • journal article
    • research article
    • Vol. 66  (2) , 203-206
Abstract
Among 460 twin pregnancies delivered at the University Central Hospital of Turku from 1970-1981, there were 41 (8.9%) with a weight difference of 25% or more between twins when calculated from the weight of the larger twin. The perinatal death rate in the 1st group (9.7%) was significantly higher (P < 0.01) than the perinatal death rate (3.7%) in the group with the weight difference of less than25%. The intrauterine mortality rate, in particular, was significantly higher (P < 0.001) in the group with 25% or more difference being 6.5-fold when compared with the group with the lower weight difference. Among 721 twin pregnancies examined by ultrasound 1-2 wk before delivery, there were 31 (11.4%) pairs of twins with a 3-mm or more difference in biparietal diameter, 11 (4.1%) with a 4-mm or more difference and 7 (2.6%) with a 5-mm or more difference. The sensitivity of measurements of biparietal diameter to detect the growth discordancy was 9-35%, the specificity 90-98% and the positive predictivity 23-29%. Apparently, a divergent growth pattern in twin pregnancy carries an elevated risk of intrauterine death, especially for the smaller twin. Measurement of biparietal diameter is not a method sensitive enough to detect these high-risk twin pregnancies.