Newer research suggests that the onset of labor is the result of a metabolic stalemate between mother and baby, a struggle of supply and demand. At some point, the large and rapidly developing fetus maxes out the nutritional and energetic supply of its mother. Rather than starve, the baby decides to make a run for it, opting to have its needs met outside the womb. This reasoning, called the energetics of gestation and growth hypothesis, is one that scientists are now exploring further.
