A follicle is "recruited" at two distinct stages of development. Early or continuous recruitment refers to the ongoing, continuous recruitment of primordial follicles to start their growth and become antral follicles, a process that is independent of major hormones, starts before birth and ends when there are no follicles left, this taking place around the time of menopause. Cyclical recruitment refers to the much later recruitment of medium-sized tertiary follicles into the ovarian cycle due to a temporary elevation of follicle stimulating hormone, which occurs at the end of each luteal phase, thus initiating a new follicular phase; the group of "recruits" susceptible to this late recruitment is called a cohort. Time-wise for a particular follicle, the two episodes of recruitment occur 8 months apart: in other words, it takes 8 months for a follicle to grow from its resting state before it can have a chance of making estrogen and then undergoing ovulation. Not all early-recruited follicles undergo later cyclical recruitment: some are lost through early atresia, many reach the stage at which they could be cyclically recruited at a stage when FSH is low (most stages of the ovarian cycle) and undergo atresia then. Readers will appreciate that ovulation induction, including intentional superovulation, can have no effect on the rate at which follicles are used up in ovaries or on the age at which menopause will occur (the different recruitment points involved are 8 months apart, with the early recruitment point governing the rate eggs are used up and the late recruitment point deciding how many follicles can respond to provide useable eggs.