Midtrimester Rh sensitization associated with circulating anticardiolipin antibodies and elevated maternal serum...

The incidence of antepartum Rh isoimmunization has been limited by third-trimester Rh immune globulin (RhIg) administration. Prophylactic failures are uncommon but can occur if sensitization takes place prior to the 28th week of gestation. We report a case of midtrimester Rh sensitization in an anticardiolipin antibody-positive primipara coincident with the discovery of an elevated maternal serum alpha-fetoprotein value, oligohydramnios and fetal growth retardation. This case suggests that fetal-maternal hemorrhage and subsequent sensitization may be facilitated by anticardiolipin antibody-induced placental damage. Prophylactic midtrimester RhIg administration might avoid sensitization in similar cases.