Bile acids in a multicenter, population-based case-control study of stillbirth

Objective: We sought to compare bile acids in women with and without stillbirth in a population-based study.

Study design: The Stillbirth Collaborative Research Network conducted a multisite, population-based case-control study of stillbirth (fetal deaths ≥20 weeks). Maternal sera were obtained at the time of enrollment and frozen at -80°C until assay for bile acids.

Results: Assays were performed in 581 women with stillbirth and 1546 women with live births. Bile acid levels were slightly higher in women with stillbirth (geometric mean [95% confidence interval {CI}] = 3.2 [3.0-3.5]) compared to live births (2.9 [2.7-3.1], P = .0327). However, the difference was not significant after adjustment for baseline risk factors for stillbirth. The proportion of women with elevated levels (≥10 or ≥40 μmol/L) was similar in stillbirths and live births. Results were similar when the analysis was limited to subsets of stillbirths and live births. In women with stillbirths not associated with fetal anomalies or obstetric complications bile acid levels were higher than in women with term live births (geometric mean [95% CI] = 3.4 [3.0-3.8] vs 2.9 [2.7-3.0], P = .0152, unadjusted; P = .06, adjusted). However, a similar proportion of women in both groups had levels ≥10 μmol/L (10.7 vs 7.2%; odds ratio [OR], 1.54; 95% CI, 0.97-2.44; adjusted OR, 1.29; 95% CI, 0.78-2.15) and ≥40 μmol/L (1.7 vs 0.7%; OR, 2.58; 95% CI, 0.85-7.84; adjusted OR, 2.28; 95% CI, 0.79-6.56).

Conclusion: Our data do not support testing for bile acids in cases of stillbirth in the absence of clinical evidence of intrahepatic cholestasis of pregnancy.