Immunocontraception outcome has focused on human chorionic gonadotropin (hCG). hCG is not necessary for fertilization, but is secreted by embryos shortly thereafter. Therefore, immunity against hCG does not prevent fertilization. However, it was found that anti-hCG antibodies prevent marmoset embryos from implanting in the endometrium of their mother's uterus. The main function of hCG is to sustain the ovarian corpus luteum during pregnancy past the time it would normally decay as part of the regular menstrual cycle. For the first 7–9 weeks in humans, the corpus luteum secretes the progesterone necessary to maintain the viability of the endometrium for pregnancy. Therefore,
Pharmacodynamics of progesterone neuropsychiatric effects associated with the menstrual cycle (e.g., dysphoria, depression, anxiety, irritability) and postpartum period (e.g., postpartum depression), as well as in catamenial epilepsy (seizures). Low and high levels of allopregnanolone seem to have a neutral effect on mood, whereas moderate levels have a negative effect, which may underlie the symptoms of premenstrual syndrome and premenstrual dysphoric disorder that are observed in 30 to 40% of premenopausal women. This U-shaped effect on mood appears to be a common property of GABA receptor positive allosteric modulators. In contrast to oral administration, parenteral progesterone, such as with vaginal administration, avoids the first-pass