For all the couples out there trying to do everything just right in the weeks leading up to conception, scientists are now suggesting that not just women but men, too, cap their caffeine consumption at two drinks per day. In other words, healthy sperm are very much a part of the equation, and the entire couple's "lifestyle factors" are associated with pregnancy loss, National Institutes of Health and Ohio State University-Columbus, researchers report in the journal Fertility and Sterility. The study followed 344 singleton pregnancies in Texas and Michigan, and observed 98 miscarriages (or 28%); the results produced three factors associated with an increased or lowered risk of miscarriage.
Specifically, the researchers found that in the window of preconception, a woman being over age 35 nearly doubled her risk of miscarriage, while her adherence to vitamins halved it; continuing to take vitamins once pregnant dropped the risk of miscarriage by 79%. Caffeine consumption by men and women, meanwhile, influenced miscarriage rates almost identically, raising risk 73% and 74%, respectively. The researchers note that this does not establish causation. As Cosmopolitan reports, it's tough to know whether women who experience the symptoms of a healthy pregnancy, such as food aversions and nausea, "naturally veer away from caffeinated beverages before they realize, 'Hey, I'm pregnant!'" which would mess with results. (A man's sperm has even been linked to his progeny's weight.)