A PROSPECTIVE EVALUATION OF FETAL PERICARDIAL FLUID IN 506 2ND-TRIMESTER LOW-RISK PREGNANCIES

Objective: To measure fetal pericardial fluid in low-risk second-trime ster pregnancies and to evaluate outcome for those with measurements g reater than 2 mm. Methods: Five hundred and six women were referred fo r sonography between 16 and 25 weeks' gestation for common obstetric i ndications (dating, fetal survey, and placental location) unrelated to an increased risk of anomalies. All cases were evaluated with two-dim ensional and M-mode real-time ultrasonography with the use of a mechan ical sector transducer. The maximum distance of the fetal hypoechoic c ardiac rim was recorded. We reviewed maternal and infant charts for th ose with measurements greater than 2 mm. Results: Median (range) mater nal age was 25 (15-42) years. Median gravidity and parity were two (1- 14) and one (0-11), respectively. Median estimated gestational age was 20.4 (16.3-24.9) weeks. Fetal pericardial fluid was seen in 360 of 50 6 (71%) fetuses. Of these 360 fetuses, the mean distance (+/- 2 standa rd deviation) of the fetal hypoechoic cardiac rim was 1.20 mm +/- 0.91 mm (95% confidence interval 1.15, 1.25). Among the 506 cases, the max imum measurement was 3 mm. Ten of the 506 (2%) cases had measurements greater than 2 mm. None of these ten fetuses had a cardiac structural abnormality or arrhythmia, and perinatal outcome was unremarkable. Con clusion: During second-trimester fetal ultrasonographic examination, v isualization of pericardial fluid up to 2 mm in the fetus with current high-resolution technology is common and should not be regarded as pa thologic. (C) 1997 by The American College of Obstetricians and Gyneco logists.