Obesity has reached epidemic proportions globally. With overweight and obesity prevalence in the US affecting about 70% of the adult population, the chance of one in a reproductive age couple being overweight/obese is high. Being overweight or obese could result in delayed pregnancy and weight loss can reverse infertility.

 

    Females who are overweight or obese are more likely to experience ovulatory and menstrual disorders and may experience delayed childbearing as a consequence. Maternal obesity is also associated with increased risks for adverse pregnancy outcomes such as miscarriage, gestational diabetes, gestational hypertension, pre-eclampsia, wound infections, etc. Increased maternal body mass index (BMI) is associated with an increased risk of perinatal death (1).

 

    A systematic review showed that weight loss before pregnancy appears to improve fertility in women with obesity. Some studies suggest that as little as 5% body weight loss may be enough to re-establish normal ovulation in a woman with anovulatory infertility due to obesity (1).

 

    Kort et al. showed that among overweight patients who were treated for infertility and referred for weight-loss counseling, women who achieved meaningful weight loss (≥10%) had significantly higher conception (88% vs. 54%) and live birth rates (71% vs. 37%) than those who did not (p<0.05). Among patients with a history of recurrent pregnancy loss, those who were able to achieve meaningful weight loss had a live birth rate twice that of those who did not (67% vs. 33%) (2).

 

    Males who are overweight or obese may also experience negative impacts on reproductive potential, not only through altering hormone levels but also by directly altering sperm function. Obesity is known to adversely affect male infertility through alteration in semen parameters (i.e. sperm concentration and motility), endocrine changes (i.e. hypogonadism), and systemic and reproductive system inflammation and oxidative stress. Obesity induces sperm DNA damage, resulting in increased apoptosis, DNA fragmentation, and epigenetic transfer to the offspring (3).

 

    Male obesity is also associated with reduced success in assisted reproductive technologies in clinical practice. Paternal obesity was a significant negative factor for sperm concentration and sperm motility and was associated with a significant decrease in clinical pregnancy rate and live birth rate (4).

 

    In a group of severely obese men, BMI was inversely associated with sperm concentration, total sperm count, sperm morphology, and motility as well as male hormone testosterone and positively associated with female hormone estradiol. The median percentage of weight loss after a weight intervention was 15%. Weight loss was associated with an increase in total sperm count, semen volume, and testosterone. The group with the largest weight loss had a statistically significant increase in total sperm count and normal sperm morphology (5).

 

    One cohort study (6) administered a nutritionist-led personalized dietary program coupled with exercise, aimed at reducing intra-abdominal fat over a 3–8 month period, to eight men who had significant abdominal fat and at least 25% sperm DNA fragmentation and unexplained infertility. The partners of all eight achieved pregnancy, three naturally and five through IUI, and all went on to have live births. Six who allowed their semen samples to be analyzed both before and after the intervention all had an improvement in the degree of sperm DNA fragmentation. Improvement in sperm DNA integrity might be linked to an improved live birth rate.

 

    Overweight and obese persons seeking fertility should be educated on the detrimental effects of fatness and the benefits of weight reduction, including improvement in pregnancy rates. A combination of a reduced-calorie diet by reducing fat and refined carbohydrate intake and increased aerobic exercise should form the basis of programs designed for such individuals (7). A healthy lifestyle and healthy body weight are important for both females and males to boost the outcome of fertility.

 

References:

1.            Price, S. A., Sumithran, P., Nankervis, A., Permezel, M., & Proietto, J. (2018). Preconception management of women with obesity: A systematic review. Obesity Reviews. doi:10.1111/obr.12804

2.            Kort, J. D., Winget, C., Kim, S. H., & Lathi, R. B. (2014). A retrospective cohort study to evaluate the impact of meaningful weight loss on fertility outcomes in an overweight population with infertility. Fertility and Sterility, 101(5), 1400–1403. doi:10.1016/j.fertnstert.2014.01.036

3.            Leisegang, K., Sengupta, P., Agarwal, A., & Henkel, R. (2020). Obesity and male infertility: Mechanisms and management. Andrologia. doi:10.1111/and.13617

4.            Umul, M., Köse, S. A., Bilen, E., Altuncu, A. G., Oksay, T., & Güney, M. (2014). Effect of increasing paternal body mass index on pregnancy and live birth rates in couples undergoing intracytoplasmic sperm injection. Andrologia, 47(3), 360–364. doi:10.1111/and.12272

5.            Håkonsen, L. B., Thulstrup, A. M., Aggerholm, A. S., Olsen, J., Bonde, J. P., Andersen, C. Y., … 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). doi:10.1186/1742-4755-8-24

6.            Faure, C., Dupont, C., Baraibar, M. A., Ladouce, R., Cedrin-Durnerin, I., Wolf, J. P., & Lévy, R. (2014). In Subfertile Couple, Abdominal Fat Loss in Men Is Associated with Improvement of Sperm Quality and Pregnancy: A Case-Series. PLoS ONE, 9(2), e86300. doi:10.1371/journal.pone.0086300

7.            Best, D., Avenell, A., & Bhattacharya, S. (2017). How effective are weight-loss interventions for improving fertility in women and men who are overweight or obese? A systematic review and meta-analysis of the evidence. Human Reproduction Update, 23(6), 681–705. doi:10.1093/humupd/dmx027