The various changes which occur in girls at puberty are: Hair grow under armpits and pubic region. Mammary glands (or breasts) develop and enlarge. The hips broaden. Extra fat is deposited in various parts of the body like hips and thighs. Fallopian tubes, uterus and vagina enlarge. Ovaries start to release eggs. Menstruation (montly periods) starts. Feelings and sexual drives associated with adulthood begin to develop.