IGCSE Biology Human Reproduction Practice Test 2026 – Complete Exam Prep

The hormone responsible for building up and thickening the uterine wall after menstruation is estrogen. After menstruation, estrogen levels rise to stimulate the regeneration of the endometrium, which is the inner lining of the uterus. This process prepares the uterus for a potential pregnancy, as a thickened endometrial lining is crucial for implantation of a fertilized egg.

Estrogen is primarily produced by the ovaries and plays a vital role in the menstrual cycle, particularly in the follicular phase, where it promotes the growth of the uterine lining in preparation for possible embryo implantation.

While progesterone also contributes to the thickening of the uterus after ovulation by preparing the lining for a potential pregnancy, it works in conjunction with estrogen, which initiates the growth. Thus, estrogen is the primary hormone responsible for the initial thickening of the uterine wall following menstruation.