Couples who are overweight or obese are more likely to have trouble conceiving than are normal-weight couples, according to a large Danish population-based study.
Among couples who were obese, the adjusted odds ratio for subfecundity was 2.74, compared with normal-weight couples. When both partners were overweight, the odds ratio was 1.41, investigators wrote in Human Reproduction.
Odds ratios were adjusted for both partners' ages, number of previous pregnancies, and socioeconomic group. Subfecundity was defined as a waiting time of at least 12 months to achieve a pregnancy that resulted in a live birth.
While previous research has shown that the weight of women and men individually affects fertility, this is the first study to examine fertility when both partners are overweight (body mass index of 25–29.99 kg/m
The researchers analyzed data from women enrolled in the Danish Birth Cohort, a nationwide study of pregnant women and their offspring, which enrolled more than 100,000 women between 1996 and 2002.
Included in the obesity study were couples who provided information on time to pregnancy and BMI for both the man and the woman. A population of 47,835 couples was analyzed for the study, 2,478 of whom had at least two births.
Obesity was reported in approximately 7% of men, 8% of women, and 1% of couples. A total of 53% of men and 68% of women were of normal weight.