ABSTRACT
The changes in hormone levels during the menstrual cycle affect both the ovaries and the endometrium. The following is a simplified account of the normal menstrual cycle. = Days 14: menstruation:
= The endometrium is shed owing to a lack of hormonal support. = Days 513: proliferative/follicular phase:
= Gonadotrophin-releasing hormone from the hypothalamus stimulates release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the pituitary gland.
