A milieu of hormones simultaneously affects development of the fetus during embryogenesis and the mother, including human chorionic gonadotropin (hCG) and progesterone (P4).
Human chorionic gonadotropin (hCG), progesterone, 17β-estradiol, endorphins and gonadotropin-releasing hormone (GnRH) synthesis are rapidly upregulated by the developing embryo following fertilization of the ovum.
hCG signaling upregulates the expression of steroidogenic acute regulatory protein (StAR)-mediated cholesterol transport and the synthesis of progesterone in hESC.
RU-486, a drug commonly used to terminate pregnancy in its early stages, acts not only to abort the embryo, but also to inhibit normal embryonic development.
[9][10] High levels of progesterone produced by the embryonic placenta regulate lymphocyte proliferation at the maternal-fetal interface, locally suppressing maternal immune response against the developing embryo.
Progesterone induces formation of tertiary side-branches in the mammary glands during puberty and during the luteal phase of the menstrual cycle upon which lobuloalveolar structures form under the influence of prolactin.