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 abnormal placental ultrasonographic findings in an unselected obstetric population and determine the usefulness of simple measurements of placental size. In addition, the relationship between these findings, uterine artery Doppler measurements, maternal serum alpha-fetoprotein levels, and subsequent pregnancy outcome was explored. STUDY DESIGN: A prospective, cross-sectional study of 210 women recruited at the time of routine ultrasonographic scan between 16 and 28 weeks' gestation was performed. Placental ultrasonographic investigations included measurements of thickness, circumference, and volume and morphologic studies. Uterine Doppler and maternal serum alpha-fetoprotein measurements were performed at the same time. RESULTS: At delivery 25 fetuses were small for gestational age, in association with hypertension in 11; 14 were delivered prematurely but were appropriately grown, and three were macrosomic. Significant correlations were found in uncomplicated pregnancies (n = 168) between gestational age and placental thickness, circumference, and volume and also between fetal abdominal and placental circumferences. Large sonolucent lakes were found with a similar incidence in 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, ultrasonographic appearances, and subsequent abnormal fetal growth or hypertensive disorders of pregnancy. The interrelationships demonstrated between the different techniques suggest that a combination of placental thickness and morphologic characteristics, uterine Doppler analysis, and evaluation of maternal serum alpha-fetoprotein level may allow more efficient screening for these complications than is currently possible using any single method.