ULTRASONOGRAPHIC INVESTIGATION OF PLACENTAL MORPHOLOGIC CHARACTERISTICS AND SIZE DURING THE 2ND TRIMESTER OF PREGNANCY

OBJECTIVE: The aim of the study was to establish the incidence of abno rmal placental ultrasonographic findings in an unselected obstetric po pulation and determine the usefulness of simple measurements of placen tal size. In addition, the relationship between these findings, uterin e artery Doppler measurements, maternal serum alpha-fetoprotein levels , and subsequent pregnancy outcome was explored. STUDY DESIGN: A prosp ective, cross-sectional study of 210 women recruited at the time of ro utine ultrasonographic scan between 16 and 28 weeks' gestation was per formed. Placental ultrasonographic investigations included measurement s of thickness, circumference, and volume and morphologic studies. Ute rine Doppler and maternal serum alpha-fetoprotein measurements were pe rformed at the same time. RESULTS: At delivery 25 fetuses were small f or gestational age, in association with hypertension in 11; 14 were de livered prematurely but were appropriately grown, and three were macro somic. Significant correlations were found in uncomplicated pregnancie s (n = 168) between gestational age and placental thickness, circumfer ence, and volume and also between fetal abdominal and placental circum ferences. Large sonolucent lakes were found with a similar incidence i n both complicated and uncomplicated pregnancies. Jelly-like placental appearance was seen in 12 of the 17 cases complicated by hypertension , 11 of which also had abnormal uterine Doppler features and elevated maternal serum alpha-fetoprotein levels. CONCLUSIONS: This study shows an association between abnormal placental development, ultrasonograph ic appearances, and subsequent abnormal fetal growth or hypertensive d isorders of pregnancy. The interrelationships demonstrated between the different techniques suggest that a combination of placental thicknes s and morphologic characteristics, uterine Doppler analysis, and evalu ation of maternal serum alpha-fetoprotein level may allow more efficie nt screening for these complications than is currently possible using any single method.