Pregnancy Outcome of Embryonic/Fetal Pleural Effusion in the First Trimester

OBJECTIVE: To investigate the incidence of embryonic/fetal pleural effusion in the first trimester and its pregnancy outcome. METHODS: A total of 965 viable singleton pregnancies confirmed by sonography between 7 and 10 weeks were examined to estimate the incidence of embryonic/fetal pleural effusion. When initial transvaginal sonography showed pleural effusion, serial ultrasound examinations were performed. RESULTS: Pleural effusion was detected in 12 pregnancies (incidence, 1.2%; 95% confidence interval, 0.7-2.2), which involved bilateral thoracic cavities in all cases. The pregnancy outcome was assessed among 14 cases of pleural effusion, including 2 previously reported cases from the same institution. Among these, 12 pregnancies (86%) miscarried by 14 weeks' gestation. Karyotype was abnormal in 9 (82%) of 11 cases in which chromosomal analysis was successfully performed. Of these, 6 (67%) were 45,X. CONCLUSIONS: The results suggested that embryonic/fetal pleural effusion in early pregnancy was associated with poor pregnancy outcome such as spontaneous abortion and chromosomal abnormality.