Lack of an association between late fetal death and antiphospholipid antibody measurements in the second trimester.

To examine the relationship between elevated antiphospholipid antibody levels in the maternal circulation and late fetal death, we carried out a case-control study in which levels of anticardiolipin and antiphosphatidylserine antibodies were measured in banked second-trimester sera from 309 pregnancies ending in fetal death and from 618 viable control pregnancies. The sera were obtained from a population base of approximately 22,000 pregnancies enrolled for maternal alpha-fetoprotein screening between 15 and 20 weeks' gestation. The anticardiolipin immunoglobulin G level was markedly elevated (15.6 SD) in one serum sample associated with a fetal death. Otherwise, the anticardiolipin and antiphosphatidylserine measurements were similar in the two populations. Several other factors known to be associated with fetal death were also examined, and these all demonstrated the expected relationship. Antiphospholipid antibody measurements obtained at 15 weeks' gestation or later in the general pregnancy population are not helpful in identifying pregnancies at risk for fetal death.