Intrahepatic cholestasis of pregnancy linked with early delivery but low stillbirth rate

Intrahepatic cholestasis of pregnancy (ICP) is associated with a 4 to 10-fold increase in the risk of stillbirth in the absence of intervention, leading to recommendations for antenatal assessment, ursodiol use, and often preterm or early term delivery. The objective of this study was to determine if current management strategies for ICP mitigate this elevated risk of stillbirth at a population level.

This is a retrospective cohort study using the 2015-2020 National Readmissions Database, an administrative database developed by the United States Agency for Healthcare Research and Quality. We identified delivery hospitalizations, gestational age at delivery, occurrence of ICP and stillbirth, and comorbid conditions using International Classification of Diseases diagnosis and procedure codes. We compared timing of delivery and stillbirth rates for pregnant patients with ICP versus those without ICP at the time of delivery hospitalization.

Results

Researchers identified a cohort of 9,987,705 delivery hospitalizations in the National Readmissions Database, corresponding to a weighted national estimate of 18,609,207 births; of these, 152,040 (0.8%) were noted to have an ICP diagnosis. Patients with ICP were older, with small differences in comorbidities such as a higher rate of gestational diabetes when compared to patients without an ICP diagnosis at delivery hospitalization. Overall rates of stillbirth were lower among those with ICP than those that did not carry that diagnosis (252 vs. 386 per 100,000 deliveries, risk difference 133 fewer per 100,000 deliveries (95% CI: 98 to 170); a finding that persisted after adjustment for insurance status, socioeconomic factors, and comorbid conditions (risk difference: 160 fewer stillbirths per 100,000 deliveries, 95% CI: 127-194). Furthermore, although ICP patients were more likely to deliver preterm than those without ICP (30.1% vs. 9.3%, p<0.001), increased rates of stillbirth were not noted at any point after stratification of the cohort by gestational age at delivery.

Patients with ICP diagnosis codes delivered earlier than those without a coded ICP diagnosis, but the percentage of births affected by stillbirth was lower, even when stratifying for gestational age at birth. These results may provide reassurance to patients receiving an ICP diagnosis that current management does mitigate stillbirth risk in ICP.

Reference:

Miriam L. Estin, Ms. Alexa I.K. Campbell, Virginia Y. Watkins, Sarah K. Dotters-Katz, Carla W. Brady, Jerome J. Federspiel. Risk of Stillbirth in US Patients with Diagnosed Intrahepatic Cholestasis of Pregnancy. American Journal of Obstetrics and Gynecology. Published:June 20, 2023DOI:https://doi.org/10.1016/j.ajog.2023.06.036

Keywords:

Intrahepatic, cholestasis, pregnancy, linked, early, delivery, low, stillbirth rate, American Journal of Obstetrics and Gynecology, Miriam L. Estin, Ms. Alexa I.K. Campbell Virginia Y. Watkins, Sarah K. Dotters-Katz, Carla W. Brady, Jerome J. Federspiel