Follicle stimulating hormone less than 5 IU/L is normal after down-regulation.
Down-regulation mainly inhibits endogenous follicle stimulating hormone and luteinizing hormone levels in the body.
Follicle stimulating hormone is the most important hormone to stimulate follicle development, which can stimulate the proliferation and differentiation of granulosa cells. In a down-regulation protocol, follicle stimulating hormone levels are measured prior to ovulation, and if they are less than 5 IU/L, down-regulation is normal, and then exogenous follicle stimulating hormone can be added to stimulate synchronized development of multiple follicles.
The human body is a single egg development and ovulation of the individual, therefore, endogenous follicle stimulating hormone positive feedback regulation, can only cause a follicle development and maturation. In vitro requires multiple follicles to develop at the same time, therefore, down-regulation is performed to inhibit endogenous follicle stimulating hormone, and then exogenous follicle stimulating hormone is added artificially to stimulate synchronized development of multiple follicles.