Why does the pelvic area of girls become wider during puberty?

During puberty, significant changes in the size and shape of body occur in both males and females. The pelvic area of girls becomes wider due to hormonal changes occurring in the body during puberty. At this time, a hormone estrogen is released which is responsible for widening the hip region. This change in body shape occurs as a means of preparing them for bearing a child. Significant deposition of fat also occurs around the pelvic area. Also the breasts develop and waist becomes smaller.