PTGS2 and pregnancy: IUGR: intrauterine growth restriction, UDCA: ursodeoxycholic acid, MDA: malondialdehyde, TBA: total bile acids, ALT: alanine transferase, AST: aspartate transferase, TB: total bilirubin, GSH: glutathione, VAS: visual analog scale, ICP: intrahepatic cholestasis of pregnancy, NAC: N-acetylcysteine, COX-2: cyclooxygenase-2