Cytogenetic evaluation of cystic hygroma associated with hydrops fetalis, oligohydramnios or intrauterine fetal death: the roles of amniocentesis, postmortem chorionic villus sampling and cystic hygroma paracentesis.

BACKGROUND: Pregnancies complicated by fetal cystic hygroma in the second and third trimesters are often associated with hydrops fetalis, oligohydramnios or intrauterine fetal death which may make genetic assessment more difficult. We investigated the roles of amniocentesis, postmortem chorionic villus sampling and cystic hygroma paracentesis in cytogenetic evaluation of cystic hygroma under such circumstances.

METHODS: Thirty-five fetuses of cystic hygroma associated with hydrops fetalis, oligohydrammos, or intrauterine fetal death were studied. All fetuses were delivered at Mackay Memorial Hospital, Taipei, Taiwan between January, 1987 and July, 1995. Data collected included maternal age, prenatal sonograms, gestational age at diagnosis, fetal karyotypes and diagnostic procedures.

RESULTS: Of 35 fetuses, all had hydrops fetalis, 19 had suffered IUFD at the time of diagnosis, and 10 had severe oligohydramnios. Cytogenetic studies were performed via amniocentesis, postmortem chorionic villus sampling, or cystic hygroma paracentesis. Successful karyotyping was achieved in 32 fetuses and the karyotype of 45,X was found in 24 fetuses. In cases with IUFD, successful karyotyping rates on cells from amniotic fluid, chorionic villi and cystic hygroma fluid were 88.9% (8 of 9), 69.2% (9 of 13) and 20% (1 of 5), respectively, whereas, in cases with living hydropic fetuses, successful karyotyping was achieved in 12 of 12 amniotic fluid and 5 of 5 cystic hygroma fluid samples.

CONCLUSIONS: Amniocentesis is a better method for cytogenetic evaluation of fetal cystic hygroma associated with intrauterine fetal death than postmortem chorionic villus sampling and cystic hygroma paracentesis. However, in the case with a living hydropic fetus and oligohydramnios, cystic hygroma paracentesis appears to be a practical alternative for cytogenetic assessment.