The menstrual cycle or periods in girls is an important part of the human reproduction cycle. While males aren’t born with reproductive organs that include ovaries and uterus, girls are born with a pair of ovaries, each of which holds thousands of extremely tiny eggs. These are all the eggs girls will ever have. Once girls reach puberty, which happens when their age is usually between 11 and 15 years, roughly in a month an ovary releases an egg due to some hormone changes in the body.
