‘Tis the season for a lot of things in December—parties, gift-giving, fa-la-la-la-la-ing—but did you know it’s also the most popular time for baby-making? Looks like it’s not just elves getting busy around the holidays!
It turns out, December is not only the time of year most people get pregnant, but it’s also the best and most fertile month for getting pregnant.
You may be wondering: “How does anyone even know that?” One word: math (plus a little bit of research).
Why is December the most common month to conceive?
To determine that the holiday season is the most popular time to make merry in the sack, the folks at e.p.t.®— the home pregnancy test manufacturer—simply counted nine months backwards from the most popular birthday in the U.S. To determine that, the company combed through birth records and found that more people in the country shared September 16 as a birthday than any other day in the year. And that makes (are you counting?) December 11 the most fertile day of the year, if all those babies were born on their due dates. In the UK, January 2 has been dubbed National Baby Making Day, which squares up with September 26 as the most popular birthday there.
While at first glance it would seem that folks would be too busy in December making lists and checking them twice, there’s evidence to suggest that lots of couples find time for a roll in the sack.
- Holiday cheer: All that partying puts couples in the mood for love. Wine helps
- Baby, it’s cold outside: Winter time in general is a good time to snuggle up with someone you love and see what happens
- Ice, ice, baby: Probably the most scientific explanation for increased fertility in December is that sperm are at their peak performance levels during the colder months, according to a study by American Journal of Obstetrics & Gynecology. In a study to explain seasonal birth patterns, researchers found that sperm morphology—or the size and shape of sperm—tends to be highest during the winter months. That’s why a lot of experts recommend you avoid wearing pants that are too tight and keep out of hot tubs also—anything that might raise the temperature of your testicles—which slows down sperm production.
Of course, a lot of December pregnancies are unplanned, which e.p.t. discovered after surveying 600 women across the country. Of those who responded, 45 percent reported that their pregnancies were unplanned—a number that corresponds with national data on unplanned pregnancies by the Center for Disease Control.
But plenty of couples getting cozy in December really want to have a baby, yet are struggling to get pregnant. SpermCheck is an over-the-counter kit you can use at home to test your sperm count and assess your fertility.
Why December might be the best time to get pregnant
In a way, it’s kind of like the universe is conspiring to get more couples to make babies in December because it also produces healthier babies than those conceived at other times of the year.
“We have seen significant seasonal differences in reproduction,” said Paul Winchester of Indiana University—where researchers found more and healthier babies were born in December—according to the news site METRO. After studying 270,000 pregnancies over five years, researchers there also determined that June is a more toxic month, leading to more premature babies.
Interestingly, that same study found that Valentine’s Day—long-thought to be the ultimate night for romance—is one of the least likely times to conceive a baby.
Sometimes, it doesn’t matter what the calendar says: You just want to make a baby. But if you’re trying to pinpoint exactly when the best time is to get pregnant, you better shave your legs in December!