Objective: To determine the associated diagnostic findings which are linked wi th adverse fetal outcome in nuchal cystic hygroma. Study design: Based on a seri es of 32 cases, we determined the sonographic morphology of the hygroma, associa ted structural anomalies, karyotypes and autopsy findings. Intrauterine fetal de ath, spontaneous abortion and abnormal karyotypes were assigned as adverse outco me parameters. Results: The mean gestational age at diagnosis was 14.4 weeks (ra nge 10-21). There were 18 nonseptated and 14 septated hygromas. Besides hygroma , associated sonographic detectable structural anomalies were observed in 17 cas es (53.1%). The greatest number of associated sonographic anomalies were hydrop s (31.3%), generalised skin oedema (6.3%) and pterygium colli (6.3%).Cytogene tic analysis revealed an abnormal karyotype in 13 of 26 (50%) invasive procedur es. Turner syndrome and Trisomy 18 (both 15.4%) were the most frequent cytogene tic abnormalities. Autopsy was performed in 24 cases and 16 cases (66.7%) had a n associated autopsy finding to hygroma colli. The most frequent associated auto psy findings were limb and craniofacial anomalies (both 25%). Only 3 (9.4%) mo thers gave birth to healthy newborns. The overall fetal adverse outcome rate was 68.8%(22 cases). Conclusions: Fetuses with NCH are at high risk for adverse ou tcome and detailed prenatal diagnosis including invasive procedures should be of fered. According to the presented autopsy findings, to determine fetal outcome i n NCH cases with normal karyotypes, detailed sonography should be concentrated b eside the exclusion of fetal heart defects and existence of hydrops fetalis, on the skeletal, urogenital and craniofacial anomalies, as these might cause severe morbidity. Study design: Based on a serials of 32 cases, we determined the sonographic morphology of the hygroma, associa ted structural anomalies, karyotypes and autopsy Results: The mean gestational age at diagnosis was 14.4 weeks (ra nge 10-21). There were 18 nonseptated and 14 septated hygromas. Besides hygroma , associated sonographic detectable structural anomalies were observed in 17 cas es (53.1%). The greatest number of associated sonographic anomalies were hydrops (31.3%), generalized skin oedema (6.3%) and pterygium colli (6.3%). Cytogene tic analysis revealed an abnormal karyotype in 13 of 26 (50%) invasive procedur es. Turner syndrome and Trisomy 18 (both 15.4%) were the most frequent cytogene tic abnormalities. Autopsy was perfor med in 24 cases and 16 cases (66.7%) had an associated autopsy finding to hygroma colli. The most frequent associated auto psy findings were limb and craniofacial anomalies (both 25%). Only 3 (9.4%) mo thers gave birth to healthy The results were as follows: newborns. The overall fetal adverse outcome rate was 68.8% (22 cases). Conclusions: Fetuses with NCH are at high risk for adverse ou tcome and detailed prenatal diagnosis including invasive procedures should be of fered. fetal outcome in NCH cases with normal karyotypes, detailed sonography should be concentrated b eside the exclusion of fetal heart defects and existence of hydrops fetalis, on the skeletal, urogenital and craniofacial anomalies, as these might cause severe morbidity.