National Geographic News, Reporting Your World Daily

Monday, November 23, 2009

Photo: Why Pregnant Women Don't Tip Over


Email to a Friend	<< Back to Full Story

A pregnant australopithecine, an early human ancestor, displays the leaned-back posture adopted by human women to help them support the load of their developing babies, as seen in an artist's conception.

A new study shows that three wedge-shaped vertebrae in women's lower backs evolved to allow pregnant females to take this posture without damaging their spines.

Australopithecine illustration courtesy John Gurche; human-chimp spine comparison © Nature