Our aim was to determine whether placental A Disintegrin-like Metalloproteinase with ThromboSpondin motif 12 (ADAMTS-12), arylesterase (ARES) levels, total oxidant status (TOS), and total antioxidant status (TAS) differ in preeclampsia, intrahepatic cholestasis of pregnancy (ICP), and uncomplicated pregnancies or not. A prospective case-control study was carried out including 84 pregnant women (26 with ICP, 28 preeclamptic patients, and 30 healthy controls). Levels of ADAMTS-12, TAS, TOS, and ARES were studied in the supernatants of placental tissue homogenates. Placental ADAMTS-12 levels were distributed as 240.9 pg/mg in ICP, 289.7 pg/mg in preeclampsia, and 310.8 pg/mg in control groups. Levels of ADAMTS-12 (odds ratio = 6.509, 95% confidence interval: 1.070-39.592, P = .042) in the placenta of the ICP were significantly lower than those in preeclampsia and control groups (P = .004), but no statistical significant difference was determined between preeclampsia and control groups. Decreased levels of placental ADAMTS-12 were found to be associated with ICP, suggesting a possible role of inflammation in the pathogenesis.