Th2/Th3 cytokine genotypes are associated with pregnancy loss.

Cytokines are critical immunoregulatory molecules, responsible for determining the nature of an immune response. It has been proposed that Th2/Th3 immune reactions support normal pregnancy, while Th1 immunity is considered detrimental to the fetus. Since cytokine production is partly under genetic control, it is possible that women suffering from a high incidence of abortions are genetically predisposed to mount a type of immune response inappropriate for pregnancy maintenance.