Obese Couples May Take Longer to Get Pregnant

Numerous research studies have detailed the various health challenges posed by obesity — Type 2 diabetes, heart disease, and cancer. But a recent study by the National Institutes of Health points to another challenge, getting pregnant.

In the study, whose findings appear online in Human Reproduction, couples, where both partners are obese, were shown to take from 55 to 59 percent longer to achieve pregnancy when compared to non-obese couples.

The study

The study followed 501 couples from Michigan and Texas from 2005 to 2009. All of the couples were part of the Longitudinal Investigation of Fertility and the Environment Study from NIH, whose goal was to examine the relationship between fertility and exposure to environmental chemicals. The women ranged in age from 18 to 44 years of age; the men were over 18 years old. Women kept journals to record their monthly menstrual cycles, intercourse, and the results of home pregnancy tests. The study followed the couples until the pregnancy was achieved or for up to one year of trying to conceive.

Researchers calculated the body mass index for each participant. Then they calculated the probability that a couple would achieve pregnancy by using a statistical measure called the fecundability odds ratio (FOR). The measure estimated the couples’ probability of pregnancy each menstrual cycle, about their BMIs.

The findings

The results showed that non-obese couples had a FOR of .1, while obese couples had a FOR of .45. That difference meant that it took the obese couples 55 percent longer to achieve pregnancy. The researchers then took into account other factors known to influence fertility, such as age, smoking status, physical activity, and cholesterol levels. When these factors were added, the obese couples’ pregnancies were delayed, even more, taking 59 percent longer when compared with the non-obese group.

The study’s authors concluded that a couple’s obesity seems to reduce fertility chances and that fertility specialists should probably take a couple’s weight status into account when counseling them about the odds of achieving pregnancy. The findings would seem to conclude that losing weight would significantly raise an obese couple’s odds of becoming pregnant.

At Women’s Health Medical Group, helping our patients achieve pregnancy and then manage it all the way through delivery is a big part of what we do. If you have any questions about your pregnancy or fertility, please don’t hesitate to call us at 817-346-5336.