Ovulation Trigger Mechanisms

Hormonal Influences

A sustained midcycle increase in estradiol causes positive feedback on the hypothalamus, which then increases GnRH secretion, leading to the LH surge, as noted by the American Journal of Kidney Diseases 1
The estradiol peak occurs before the LH surge and ovulation, but estrogen itself does not directly cause ovulation, according to the American Journal of Kidney Diseases 1
The LH surge is the direct trigger for ovulation, with a 2-4 fold increase above baseline levels, however no reference is provided for this statement, but the role of estrogen is indirect, not direct, as stated by the American Journal of Kidney Diseases 1 and Praxis Medical Insights 2

Ovulation follows a sharp increase in luteinizing hormone, estrogen, and FSH levels during the follicular phase, as reported by the Sports Medicine guideline society 3