Effect of mild hepatic or renal impairment on maternal serum screening biochemical measures.

BACKGROUND: Integrated maternal serum screening (MSS) is commonly used to screen for fetal trisomies and neural tube defects in early pregnancy. The kidney and liver each play an important role in hormone metabolism, and anecdotal data suggest that MSS biochemical measures may vary with a mother's health status. We examined the correlations between kidney and liver function parameters and MSS markers and the possible association of mild renal or hepatic impairment with MSS measures.

METHODS: We completed a prospective cross-sectional study of 257 consecutive women who underwent integrated MSS at a single hospital. Serum analytes (pregnancy associated plasma protein A [PAPP-A], hCG, creatinine [Cr], and alanine aminotransferase [ALT]) were drawn at approximately 12 weeks' gestation, and alpha-fetoprotein and unconjugated estriol were drawn at 16 weeks' gestation. Creatinine clearance was calculated using the Cockcroft-Gault formula. Abnormally elevated serum Cr and ALT were each defined as ≥ 90th percentile among all women. A low creatinine clearance (CrCl) was set at ≤ 10th percentile.

RESULTS: Serum hCG, PAPP-A, and alpha-fetoprotein were negatively correlated with CrCl, but not after correction for maternal age, weight, and ethnicity. No association between MSS and serum ALT was observed. The median serum concentrations of both PAPP-A (P = 0.04) and alpha-fetoprotein (P = 0.02) were significantly higher among those whose CrCl was ≤ 10th percentile. At the more extreme concentrations of PAPP-A and alpha-fetoprotein, no significant association with a low CrCl or an elevated serum ALT was seen.

CONCLUSIONS: Among a group of apparently healthy pregnant women, mild renal or hepatic impairment had little or no significant correlation with individual MSS markers. Further work should focus on the effect of more severe renal or hepatic dysfunction on MSS measures.