Optimizing BMI in women and men improves fertility and reduce the miscarriage risk: Study

A new study conducted by Aline Boxem and team showed that improving body mass index (BMI) in both men and women starting in the preconception stage may be a key tactic to increase fertility and lower the chance of miscarriage. The findings of this study were published in the Journal of American Medical Association.

Obesity in women who are fertile poses a serious threat to public health. Being overweight or obese is linked to a longer period until pregnancy is obtained in infertile people. It is possible that there is more to the relationship between body mass index and early pregnancy outcomes than just obesity. It is currently unknown what the ideal BMI is in relation to early pregnancy outcomes. In addition to BMI in women, there is mounting evidence among subfertile people that BMI in men is similarly linked to miscarriage risk and reproductive outcomes. Thus, this study was to look at the relationships between the BMIs of both spouses before conception and the length of time it took to become pregnant or miscarry.

Between August 9, 2017 and July 1, 2021, population-based prospective cohort research was carried out in Rotterdam, Netherlands. From the time of preconception till delivery, 3604 women and their partners were involved in the follow-up. BMI determined during the early stages of pregnancy or before conception. Fecundability is the likelihood of becoming pregnant in less than a month whereas, subfertility is the amount of time it takes to become pregnant, the length of time it takes to actively pursue a pregnancy, or the use of assisted reproductive technologies. Miscarriage is the loss of a pregnancy before 22 weeks of gestation. Both the obstetric caregiver and questionnaires were used to evaluate these parameters.

• The research population for time-to-pregnancy analysis included 3033 events in women and 2288 in males.
• Higher BMI in both men and women was related to poorer fecundity: fecundity dropped with each unit rise in BMI.
• Those who were overweight or obese had decreased fertility rates than those who were normal weight.
• In women, being underweight, overweight, or obese was related to an increased risk of subfertility when compared to normal weight.
• Obesity in male was linked to an increased risk of subfertility.
• Overweight and obesity were related to a higher risk of miscarriage in women than normal weight.

Overall, BMI above or below the normal range in both men and women was related with reduced fecundity, subfertility, and an increased risk of miscarriage.

Source:

Boxem, A. J., Blaauwendraad, S. M., Mulders, A. G. M. G. J., Bekkers, E. L., Kruithof, C. J., Steegers, E. A. P., Gaillard, R., & Jaddoe, V. W. V. (2024). Preconception and Early-Pregnancy Body Mass Index in Women and Men, Time to Pregnancy, and Risk of Miscarriage. In JAMA Network Open (Vol. 7, Issue 9, p. e2436157). American Medical Association (AMA). https://doi.org/10.1001/jamanetworkopen.2024.36157