Ovulation - Follicular Waves

Follicular Waves

Research spearheaded by Baerwald et al. suggests that the menstrual cycle may not regulate follicular growth as strictly as previously thought. In particular, the majority of women during an average twenty-eight day cycle experience two or three "waves" of follicular development, with only the final wave being ovulatory. The remainder of the waves are anovulatory, characterized by the developed preovulatory follicle falling into atresia (a major anovulatory cycle) or no preovulatory follicle being chosen at all (a minor anovulatory cycle).

The phenomenon is similar to the follicular waves seen in cows and horses. In these animals, a large cohort of early tertiary follicles develop consistently during the follicular phase of the menstrual cycle, suggesting that the endocrine system does not regulate folliculogenesis stringently. Researchers of fertility awareness or natural family planning methods discovered follicular waves in the 1950s. These methods of family planning have always taken multiple follicular waves into account, and this research does not challenge their effectiveness.

The gene Lrh1 appears to be essential in regulating ovulation.