Placental protein distribution in maternal diabetes mellitus: an immunocytochemical study.

Placentas associated with maternal diabetes are generally characterized by features of villous immaturity. We correlated the villous histology with the immunocytochemical distribution of four trophoblastic proteins: beta human chorionic gonadotropin (beta HCG), placental alkaline phosphatase (PLAP), pregnancy specific beta-1-glycoprotein (SP1), and human placental lactogen (HPL) in 14 third-trimester placentas associated with diabetes mellitus. Staining was increased for beta HCG and decreased for PLAP, SP1, and HPL in the diabetic placentas compared to control placentas of similar gestational age. This pattern was most prominent in areas of marked architectural villous immaturity within individual placentas and suggests concomitant functional immaturity.