Infertility in women or men is a highly prevalent problem worldwide. Van Der Steeg reported that a unit increase in BMI above 29 kg/m2 is associated with a 5% reduced probability of pregnancy in women. Plus, obesity is an independent risk factor for miscarriages. Though infertility is not always related to lifestyle, rarely lack and often excess body fat can induce this issue in many.
While there are several reasons for women’s infertility problems, the commonly observed problem is hormonal imbalance, often rooted in very low or high body fat issues.
In Polycystic Ovarian Syndrome (PCOS), the inability of an egg to get released leads to a surge in luteinizing hormone, which then increases testosterone levels. Women with PCOS show changes in facial structure, face hair, acne on the face and body, and male pattern baldness due to the excess of testosterone. PCOS is radiographically characterised by the occurrence of cysts in the ovaries.
In obesity, fat cells tend to secrete more inflammatory substances, and they contribute to increased insulin resistance. This also negatively affects follicular (sacs in ovaries that contain an egg each) growth. In addition, insulin resistance aggravates Polycystic Ovarian Syndrome and reducing the same is reported to show significant development in such patients. Hence, gynaecologists often prescribe metformin to their patients, a drug that improves insulin sensitivity.
Another effective way to reduce insulin resistance is 5-10% weight loss. Crosignani reported resumption in regular cycles of the majority of PCOS patients that underwent weight loss, ten women among the group were able to conceive. The addition of aerobic or anaerobic exercise in the lifestyle also promotes insulin sensitivity.
Man being overweight is also associated with prolonged time to achieve pregnancy, and weight loss in overweight men seems to increase sperm count and quality considerably. Hence, the benefits of weight loss are consistent in individuals with obesity and PCOS.
The relationship between body fat and natural hormonal balance is not entirely inverse. Lower body fat than standard has been shown to reduce fertility. Being at lower body fat levels can severely impact the regularity of the mensural cycle in women, which can hinder pregnancy plans. Moreover, lower than normal BMI in men has also been associated with lower semen quality.
Maintaining a healthy body mass index (with healthy body composition) will go a long way in addressing issues in the fertility of both partners. It will also increase the chances of a healthy delivery.
References:
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Crosignani, P. G. et al. (2003) ‘Overweight and obese anovulatory patients with polycystic ovaries: Parallel improvements in anthropometric indices, ovarian physiology and fertility rate induced by diet’, Human Reproduction, 18(9), pp. 1928–1932. doi: 10.1093/humrep/deg367.
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Dağ, Z.Ö. and Dilbaz, B., 2015. Impact of obesity on infertility in women. Journal of the Turkish German Gynecological Association, 16(2), p.111.
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Flegal, K.M., Shepherd, J.A., Looker, A.C., Graubard, B.I., Borrud, L.G., Ogden, C.L., Harris, T.B., Everhart, J.E. and Schenker, N., 2009. Comparisons of percentage body fat, body mass index, waist circumference, and waist-stature ratio in adults. The American journal of clinical nutrition, 89(2), pp.500-508.
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Guo, D., Xu, M., Zhou, Q., Wu, C., Ju, R. and Dai, J., 2019. Is low body mass index a risk factor for semen quality? A PRISMA-compliant meta-analysis. Medicine, 98(32).
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Håkonsen, L.B., Thulstrup, A.M., Aggerholm, A.S., Olsen, J., Bonde, J.P., Andersen, C.Y., Bungum, M., Ernst, E.H., Hansen, M.L., Ernst, E.H. and Ramlau-Hansen, C.H., 2011. Does weight loss improve semen quality and reproductive hormones? Results from a cohort of severely obese men. Reproductive health, 8(1), pp.1-8.
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Landres, I.V., Milki, A.A. and Lathi, R.B., 2010. Karyotype of miscarriages in relation to maternal weight. Human reproduction, 25(5), pp.1123-1126.
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Ryan, D. H. and Yockey, S. R. (2017) ‘Weight Loss and Improvement in Comorbidity: Differences at 5%, 10%, 15%, and Over’, Current Obesity Reports. NIH Public Access, 6(2), pp. 187–194. doi: 10.1007/s13679-017-0262-y.
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Van Der Steeg, J.W., Steures, P., Eijkemans, M.J., Habbema, J.D.F., Hompes, P.G., Burggraaff, J.M., Oosterhuis, G.J.E., Bossuyt, P.M., Van Der Veen, F. and Mol, B.W., 2008. Obesity affects spontaneous pregnancy chances in subfertile, ovulatory women. Human reproduction, 23(2), pp.324-328.
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Zanker, C.L., 2006. Regulation of reproductive function in athletic women: an investigation of the roles of energy availability and body composition. British journal of sports medicine, 40(6), pp.489-490.
