RESUMEN
OBJECTIVE: To investigate the outcome of fetuses with cystic hygroma (CH) diagnosed at the first trimester from a general population in Hong Kong. METHOD: This was a prospective study of 30 fetal cystic hygroma detected at 11 to 13 + 6 weeks' gestation in 8835 sequential unselected pregnancies. Fetal cystic hygroma was categorized as isolated cystic hygroma (ICH) or associated cystic hygroma (ACH) according to the presence of associated multiple congenital structural abnormalities (MCA). RESULTS: There were 10 cases of ICH and 20 cases of ACH. The karyotypes were obtained in 29 cases. In the ICH, 30% (3/10) were associated with chromosomal abnormalities. In the ACH, 65% (13/20) were associated with major chromosomal abnormalities. CONCLUSION: This study suggests that the prognosis of cystic hygroma detected in the first trimester is guarded, with high incidence of MCA (66.7%, 20/30) and chromosomal abnormalities (53.3%, 16/30). The findings support detailed ultrasound examination and invasive prenatal diagnosis for cystic hygroma.