Science backs up these pregnancy superstitions

Most of the folk wisdom that well-meaning older relatives offer up to expectant mothers can be easily ignored: Carrying the baby lower in the abdomen isn’t a sign that it’s a boy, or a girl, or anything other than an indication your abdominal muscles have loosened up a bit.

Your cravings won’t manifest themselves as birthmarks on the kid’s skin. Long walks won’t induce labor.

And no, the full moon has nothing to do with the timing of the birth.

But in recent years, a handful of studies have found that some of the most outlandish old ideas concerning babies and pregnancy may have some scientific merit after all.

Here are a few that superstitious grandmothers everywhere can put in the win column.

A long, difficult labor means the baby’s a boy.Researchers aren’t quite sure why this one’s true, but nonetheless: In 2003, a team of doctors analyzed more than 8,000 births at a single hospital in Ireland between 1997 and 2000, excluding women who delivered prematurely or needed to induce labor. When they crunched all the numbers, the difference between the sexes was small but noticeable.

On average, labor for boy births lasted a little over six hours, while girl births took a little under six. Women delivering boys were also more likely to run into complications during delivery, requiring C-sections 6 percent of the time (compared to 4 percent for girls) and forceps in 8 percent of cases (as opposed to 6 percent).

Overall, 29 percent of boy deliveries ended up requiring some sort of extra intervention; for girls, it was 24 percent.

One possible reason for the discrepancy: Boys, on average, weigh three and a half ounces more at birth than girls do. And a small 2003 study found that women carrying boys also consume more calories during pregnancy, suggesting that male babies are a little more demanding even before delivery starts.