Placenta 'Switch' that Kickstarts Labor May Solve Long-Standing Mystery

As any 40-weeks'-pregnant woman can attest, predicting when labor might start is a dark art — which is to say, basically impossible. Now, a new study suggests that a genetic "switch" in the placenta might kick off the production of the hormones that start labor. "It's 2015, and even now we don't understand how the clock works that governs the length of pregnancy," said study researcher Dr. Todd Rosen, chief of maternal-fetal medicine at the Rutgers University Robert Wood Johnson Medic