What is the primary function of estrogen in the menstrual cycle?

The primary function of estrogen in the menstrual cycle is to develop secondary sexual characteristics and to regulate several processes related to the reproductive system. During the menstrual cycle, estrogen is primarily produced by the developing follicles in the ovaries. It plays a crucial role in the thickening of the endometrial lining, preparing the uterus for potential implantation of a fertilized egg.

Additionally, estrogen influences the development of breast tissue, the distribution of body fat, and menstrual cycle regulation. The increase in estrogen levels during the follicular phase also stimulates the release of luteinizing hormone (LH), which leads to ovulation. Ultimately, its role in promoting secondary sexual characteristics ties closely to its broader functions in reproductive health across the menstrual cycle.