The question of how pregnant women manage to avoid toppling over due to their huge bump has finally been answered. Scientists have discovered an elegant piece of evolutionary engineering that allows the female spine to balance the extra load.
There is a difference in the lower backbones and hips between men and women which has developed over millions of years that allows women to carry a foetus while maintaining an upright posture. Women’s lower vertebrae are wedge-shaped and their hip joints are slightly bigger than men’s.
Women’s lower spines have evolved greater flexibility and support than that of a man and as a foetus and placenta can together weigh almost 7 kg (15.4 lb), the extra load then moves the centre of gravity to the front of the hips which forces the women to lean back.
Daniel Lieberman, of Harvard University, said: “Early human women lived very strenuous, active lives and were forced to cope with the discomfort of childbearing while foraging for food and escaping from predators. This evolution helped early women to remain more mobile during pregnancy, which would have been essential to survival.”
