Extreme second-trimester serum analyte values in down syndrome pregnancies with hydrops fetalis.

OBJECTIVE

To compare second-trimester maternal serum analyte values in Down syndrome pregnancies with, and without, hydrops fetalis.

METHODS

Seven hydropic and 85 non-hydropic Down syndrome pregnancies were identified among women with positive second-trimester maternal serum screening results. Values for maternal serum alpha-fetoprotein (MSAFP), human chorionic gonadotropin (hCG), unconjugated estriol and inhibin-A, and risks for Down syndrome were compared using the non-parametric Mann-Whitney statistical test.

RESULTS

Hydropic Down syndrome pregnancies had significantly lower MSAFP and estriol concentrations, while hCG levels were higher. For subgroups of five hydropic and 42 non-hydropic cases, no statistically significant difference in the inhibin-A levels could be demonstrated.

CONCLUSION

Second-trimester Down syndrome screening risks are significantly higher in affected pregnancies that are complicated by fetal hydrops.