Here’s the Surprising Reason Pregnancy Lasts 9 Months

Anyone who has been pregnant will agree that growing an entire human seems a whole lot longer than 9 months. In the third trimester, time seems to move in special pregnancy slow motion where each day gestating is equal to about 5 days in real time. But have you ever wondered why pregnancy is 9 months long? Human babies are born in a very dependent state and doctors often refer to the first few weeks of their life as the fourth trimester. Scientists had long held the belief that the reason babies are born underdeveloped compared to other primates was because if they stayed any longer their heads wouldn't fit through the mother's birth canal. But now this theory has been turned on its head. Anthropologist Holly Dunsworth, from the University of Rhode Island has discovered that babies are, in fact, born at this stage because a woman's metabolism means her body simply couldn't sustain a pregnancy for much longer. Her research, reported in the Journal Proceedings of the National Academy of Science, now firmly dispels the hip measurement theory. During pregnancy, women are using twice their usual energy sustaining their normal metabolic system. We can only typically sustain between two and two and a half times the average metabolic rate. This study shows that the reason we gestate for nine months is nature's balance of developing the baby but while also preserving the mother's health. Dr Dunsworth says :

"There is a certain capacity a mother has metabolically, and once that capacity is reached, the baby is born."