OBJECTIVE The pathogenesis of intrahepatic cholestasis of pregnancy (ICP) involves impaired bile acid and estrogen/progesterone metabolism and excretion based on genetic and environmental factors. The role of vitamin D is undefined. METHODS Observational study. METHODS Department of Obstetrics and Gynecology, Danderyd Hospital, Stockholm, Sweden. METHODS Swedish. METHODS We measured serum 1,25-dihydroxy vitamin D3 (1,25-D3) and parathormone in 22 women with ICP at presentation, in comparison with 11 healthy women at delivery. RESULTS ICP women had significantly (p = 0.0041) lower levels of 1,25-D3 in serum (76.4 ± 23.1 vs. 112.0 ± 40 ng/L, mean ± SD), unrelated to serum bile acids. 1,25-D3 levels were inversely correlated (p < 0.05) to meconium staining of amniotic fluid. Parathormone levels did not differ between ICP and healthy women. CONCLUSIONS Lower 1,25-D3 levels in ICP are inversely correlated by meconium staining, a major indicator of fetal distress. Our finding may have pathogenetic and clinical implications since vitamin D regulates steroid metabolism and 1,25-D3 deficiency may impair fetal outcome.