Can pregnancy lower lymphocyctes?

Yes: Pregnancy does lower the maternal lymphocyte count. This is related to the development of chorionic gonadotropin produced to protect the fetus. Human chorionic gonadotropin completely inhibits the response of lymphocytes to phytohemagglutinin. This effect is reversible and supports the theory that the fetus is accepted because chorionic gonadotropin blocks both the level as well as action of maternal lymphocytes.