Risk of obstetric cholestasis in sisters of index patients

The aim of the present study was to evaluate the rate of intrahepatic chole stasis of pregnancy in first-degree relatives of index patients. Index pati ents (n = 65) with singleton pregnancies complicated by intrahepatic choles tasis were identified among the women (n = 11984) who gave birth at Kuopio University Hospital in 1994-1998. The pregnancy histories of relatives of 5 6 index patients were reviewed and the rate of cholestasis in first-degree relatives was compared with that in the general obstetric population. Obstetric cholestasis was experienced by 9% of the parous sisters and 11% o f the mothers of the index patients. The risk per delivery was 6% in the fi rst-degree relatives. The rate in the general obstetric population was 0.54 %. The odds ratios and 95% confidence intervals were 12.6 (5.6-28.1) for th e sisters and 12.2 (6.2-24.2) for the mothers. Obstetric cholestasis cluste rs within some families and is under strong genetic influence, although the precise genetic pattern remains obscure. The sisters of index patients are at an increased risk of the disorder and may benefit from close obstetric care.