Gestational diseases -- a workshop report.

Between 11% and 20% of all clinically recognised pregnancies are lost before the 20th week of gestation, with huge financial and personal implications. Immune mechanisms have been proposed to play a role in unexplained recurrent miscarriage. Considerable attention has focused on endometrial leucocyte populations in recurrent miscarriage, although the underlying pathogenesis remains largely unexplained. The mechanisms underlying sporadic miscarriage are even less well understood, although aneuploidy is the commonest attributable cause of early (<or=12 completed weeks gestation) sporadic miscarriage. Hydatidiform mole is a rare cause of early pregnancy loss with marked geographical variation in incidence. Both complete and partial hydatidiform mole are associated with excessive trophoblast proliferation and hence provide an opportunity to study trophoblast growth regulation.