During a normal menstrual cycle, the body usually develops one follicle each month. This follicle matures and releases an egg, while the hormones estrogen and progesterone work to thicken the uterine lining (endometrium) to support a potential pregnancy. If fertilization does not happen, the lining sheds as a menstrual period. Most women have cycles that occur every 21 to 35 days and last about four to seven days. However, hormonal imbalances can disrupt this process, leading to skipped or irregular periods due to lack of ovulation.