The seed to success: The role of seminal plasma in pregnancy.

A lack of immunologic tolerance of the mother toward her child and in placentation can result in early or late pregnancy complications, including implantation failure, miscarriage, preeclampsia, and fetal growth restriction. Seminal plasma has the potential of influencing the maternal immune system for acceptance of the semi-allogeneic fetus. Here we elaborate on studies which provide evidence that an optimal balance of pro-inflammatory and immunomodulatory factors is necessary for the induction of immunologic tolerance and the process of implantation and placentation. Seminal plasma is a source of immunological mediators at conception, which can influence the function of maternal immune cells. Identifying the relevant factors in seminal plasma and the mechanisms by which they affect the maternal reproductive tract in relation to pregnancy outcome is a challenge for future research.