It is often believed that the time from one period to the next is a fixed twenty eight days. Periods last on average between four to six days although they may be as short as two days or as long as eight days.
Young girls having their first period at younger age nowadays (9-16) compared to fifty years ago probably due to better nutrition.
The end of woman’s period is call menopause. Menopause normally start around 46-52 years although any time between 40 and 60 is normal.
The pill and contraceptive
a) Combined oral contraceptive pill (estrogen & progesterone) – Change the delicate hormone balance of normal menstrual cycle so that no egg is released from the ovaries. Woman on a combined pill should have some bleeding during the six or seven pill free days; the pills hormones cause the womb lining to build up slightly and stopping the pill means that the lining is shed. This is not a period in the usual way, but is called the pill withdrawal bleed.