reproduction

The first phase of the menstrual cycle in the uterus is the proliferative phase. The proliferative phase is the time after menstruation and up to ovulation. When menstruation is over, the endometrium (lining of the uterus) grows and thickens during this phase to prepare for the implantation of an embryo (fertilized egg).

During the proliferative phase in the uterus, the hormone estrogen is released from the maturing Graafian follicles in the ovaries.