Prenatal sonographic findings of trisomy 18: review of 47 cases.

Prenatal sonographic findings were reviewed in 47 consecutive fetuses with trisomy 18. One or more abnormalities, excluding choroid plexus cysts, were found in 39 fetuses (83%), including 21 of 29 (72%) fetuses examined between 14 and 24 weeks and all 18 (100%) fetuses examined after 24 weeks. Abnormalities most frequently detected before 24 weeks included cystic hygromas, nuchal thickening, and meningomyelocele. Intrauterine growth retardation, cardiac defects, and an enlarged cisterna magna were detected more frequently after 24 weeks than before 24 weeks (P<0,05)