Immunocytochemical staining patterns of placentas associated with hydrops fetalis.

This study examined the morphology and immunocytochemical staining patterns of distribution of beta-human chorionic gonadotropin (beta-HCG), human placental lactogen (HPL), placental alkaline phosphatase (PLAP), and pregnancy-specific beta-1 glycoprotein (SP1) in 13 third-trimester placentas associated with hydrops fetalis and six normal control placentas matched for gestational age (+/- 2 weeks). Seven placentas were hydropic (540-1,080 g) and demonstrated histologic immaturity with large edematous chorionic villi showing few blood vessels, most of which contained immature hematopoietic elements. These placentas showed consistently increased staining for beta-HCG and decreased staining for PLAP when compared with control placentas, a pattern reminiscent of less mature placentas. HPL and SP1 staining were similar to those of controls. Six placentas were either sclerotic (four) or histologically unremarkable (two), and these did not differ in their immunocytochemical staining properties from control placentas. We conclude that third-trimester hydropic placentas, in addition to showing histologic immaturity, exhibit an immunocytochemical staining pattern associated with first-trimester placentas.