Are You Normal Ovulation?

Normally, one of the ovaries releases a single mature egg every month, and this is called ovulation. Women may notice pain or abdominal discomfort at the time of ovulation and occasionally have some slight vaginal bleeding. The presence of regular periods, premenstrual tension and dysmenorrhoea (period pains) usually indicate that the menstrual cycles are ovulatory.

Eggs are stored in the ovaries in follicles. Follicles exist in two major categories – growing and non-growing ( primordial ). Eggs in the primordial follicle are in a very immature form. In this state they are not capable of being fertilized by a sperm until they undergo a maturing process which culminates in their release from the ovary at the time of ovulation. Egg maturation and ovulation is stimulated by two hormones secreted by the pituitary - follicle stimulating hormone (FSH) and luteinizing hormone (LH) . These two hormones must be produced in appropriate amounts throughout the monthly cycle for normal ovulation to occur. Every month, at the start of the menstrual cycle, in response to the FSH produced by the pituitary gland, about 30-40 primordial follicles start to grow. Of these, only one matures to form a large fluid-filled structure, called a Graafian follicle which contains a mature egg, while the others die ( a process called atresia). The mature egg is released from the follicle when the follicle ruptures in response to a surge of LH produced by the pituitary.

After ovulation has occured, the follicle from which the egg has been released forms a cystic structure called the corpus luteum. This is responsible for progesterone production in the second half of the cycle.

Most women who have regular periods have ovulatory cycles. Women who fail to ovulate or who have abnormal ovulation usually have a disturbance of their menstrual pattern. This may take the form of complete lack of periods (amenorrhoea), irregular or delayed periods (oligomenorrhoea) or occasionally a shortened cycle due to a defect in the second part (luteal phase) of the cycle.