First trimester cystic hygroma: does early detection matter?

OBJECTIVE: To describe the association of abnormal outcomes with fetal cystic hygroma detected when crown-rump length measures less than 45 mm, and to compare them to outcomes among fetuses with cystic hygroma detected when crown-rump length measures 45-84 mm.

METHODS: We performed a retrospective cohort study of fetuses with first trimester nuchal cystic hygroma from 2005 to 2015.

RESULTS: A total of 212 fetuses were included. Abnormal karyotype was found in 20 of 46 (43.4%) fetuses with cystic hygroma detected when crown-rump length measured below 45 mm, compared to 108 of 148 (73%) fetuses with cystic hygroma detected at crown-rump lengths of 45-84 mm (p = 0.001). There were no differences in rates of major structural anomaly (27% vs 36%; p = 0.53) or pregnancy loss (23% vs 7%; p = 0.22) among fetuses with normal karyotype. Those with cystic hygroma diagnosed at crown-rump lengths below 45 mm were more likely to have a normal neonatal outcome compared to cases diagnosed with crown-rump lengths of 45-84 mm (25% vs 11%; p = 0.02).

CONCLUSION: Cystic hygroma detected when crown-rump length measures below 45 mm have lower rates of chromosomal abnormalities and a higher proportion of normal birth outcomes when compared to those detected later in the first trimester. © 2016 John Wiley & Sons, Ltd.