Dad's (Not Mom's) Weight Affects Chances Of Conception, Study Shows


Mom’s weight has really been under the pregnancy microscope lately. We’ve learned from study after study that if mom’s weight is too high before and during pregnancy, it can have unhealthy consequences for her baby. But apparently  a woman’s weight is not the only number on the scale that matters when it comes to a healthy pregnancy.  A new study shows that if dad’s weight is too high, there may not be a baby in the first place.

At least not when it comes to pregnancies conceived via In Vitro Fertilization. A new study determined that IVF success rates go down as Dad’s weight goes up.

It’s not even quite clear why this happens. Examinations of the men before the procedures showed no difference in sperm count, quality or motility. Pre-implantation measurements of the three day old embryos were comparable across all weight ranges. And yet, the study found that the more a man weighed, the less likely IVF was to be successful. And the difference in success rates were signifciant.

The study, conducted at Albert Einstein College of Medicine and Montefiore Medical Center in New York City,   found that overweight men were 28% less likely to conceive than normal weight men. And men whose Body Mass Index put them in the obese category had their chances of successful IVF conception slashed by 56%.

“In a multivariate analysis adjusting for potential confounders, including female BMI, female age, semen concentration, type of assisted reproductive technology, and number of embryos transferred, only an increase in male BMI and the number of embryos transferred were associated with odds of clinical pregnancy.”

So the effect of the weight variable made a difference in the success of IVF even when other variables were excluded.

It’s  hard to know what to make of these results. But I’m always interested in any discovery that take some of the responsibility for successful childbearing off the mom’s shoulders and puts it on the Dad’s. As endless studies report the various ways in which mom’s choices (or inability to prevent things she had no choice about) affect kids’ lives forever, Dads have seemed to get off pretty easy. But maybe that’s just because not enough has been discovered yet!

photo: Mr. Thomas/flickr