The hormones circulating in the bloodstream start the reproductive organs working. These organs are located in the pelvic region and include the uterus, cervix and the ovaries. As well as producing the hormone oestrogen, which triggers all the other changes in the body, the ovaries produce ova (eggs).
During puberty, the ovaries grow in size and start releasing those eggs, preparing the body for life as a woman. The start of the period also signifies that the female body is ready to have babies.
Every month, a woman’s body prepares for a possible pregnancy. Her uterus will grow a lining that is suitable for a baby to grow. It starts to thicken with blood in preparation for the arrival of a fertile egg. The uterus is where a new life would start and grow if the egg was fertilised by male sperm. The thickened lining waits for an egg to be released from one of the ovaries and travel down the tube that connects the ovary and uterus. If the egg is not fertilised, the lining of the uterus starts to break apart around 14 days after the egg was released.
If the woman doesn’t become pregnant, her body must lose this special lining by having a period. The blood travels out of the uterus through the cervix and is then released through the vagina out of the body. The body goes through the same process again next month.
The whole process, from the build-up of the lining to the discharge as a period, is called the menstrual cycle, and every woman has one approximately every 28 days. When periods first begin, they can be irregular – sometimes occurring three weeks apart, and then nearly six weeks before the next. In time, they should become more regular and predictable.
