During the first 11 days of the cycle, estrogen exerts negative feedback control over the secretion of LH and FSH. This decrease in FSH causes the regression of all the follicles except the emerging dominant follicle. Eventually, however, the estrogen levels increase to such a degree that the mode of control regarding LH shifts from negative feedback to positive feedback. In other words, estrogen increases rapidly in the late follicular phase and triggers the LH surge.

Hormonal control of the menstrual cycle is rarely understood from the first source. This is a topic for which learning is really helped by getting a number of narrations.












The WikiPremed MCAT Course is a comprehensive course in the undergraduate level general sciences. Undergraduate level physics, chemistry, organic chemistry and biology are presented by this course as a unified whole within a spiraling curriculum. Please read our policies on Privacy and Shipping & Returns.  Contact Us. MCAT is a registered trademark of the Association of American Medical Colleges, which does not endorse the WikiPremed Course. WikiPremed offers the customers of our publications or our teaching services no guarantees regarding eventual performance on the MCAT.


Creative Commons License
WikiPremed is a trademark of Wisebridge Learning Systems LLC. The work of WikiPremed is published under a Creative Commons Attribution NonCommercial ShareAlike License. There are elements of work here, such as a subset of the images in the archive from WikiPedia, that originated as GNU General Public License works, so take care to follow the unique stipulations of that license in printed reproductions.