Weight loss intervention to improve reproductive outcomes in obese, subfertile women
The study provides evidence that weight loss in severely obese women improves metabolism and significantly helps ovulation. Most obese women have low fertility compared to women of normal weight. However, there are obese women who face no subfertility issues.
Obese women show impaired fecundity both as to natural and assisted conception. Studies have shown severe anovulatory due to hyperandrogenism and polycystic ovary syndrome. At the same time, studies also indicate that obese people have sexual intercourse less often compared to people who maintain a normal weight. Therefore, obese women experience sexual dysfunction and tend to delay pregnancy. However, weight loss could boost their self-esteem particularly with regard to intimacy and sexual health issues.
Three large studies have shown lower pregnancy rates in moderately and severely obese women as well as insulin resistance and compensatory hyperinsulinemia. A weight loss of 5% or more is shown to lead to normalization of the reproductive system further to restoration of the menstrual cycle in women with and without polycystic ovary syndrome.
Studies in models, both animals and humans, have shown that increased weight during pregnancy is associated with adverse risks while weight loss can reduce risks (for example, in obese women with Type 2 diabetes).
Zhang et al. have demonstrated that a limitation in energy intake before conception may prove beneficial and reduce complications. In their studies, investigators imposed an approximately 40% restriction in energy intake in order to reduce weight by approximately 15% for a period of time during which body weight is to remain stable.
Participants were allowed an intake of 1200-1500 calories per day. Phelan et al. studied a low-intensity behavioral intervention in obese women during pregnancy but not before pregnancy. Out of the 1,499 women participating in the study, 401 (i.e. 26%) were randomized and only 320 (i.e. 82%) completed the six-month assessment. This intervention reduced excessive weight gain in women of normal weight but not in overweight or obese women.
Short-term weight loss is safe and effective and has shown significant improvements in diastolic blood pressure and the mental health of the participants. Weight loss in the framework of this study was between 6 to 14 kg, while participants’ insulin sensitivity also improved. Three out of six women (50%) who participated in the study became pregnant within 6 months following the end of the intervention; two participants successfully conceived after one cycle of Clomiphene and one conceived without ovulation induction.
None of the women who did not participate in the intervention managed to conceive despite being submitted to three cycles of Clomiphene. A 15% short-term weight loss within 16 weeks in women with a BMI of 35 to 45 kg/m2 is more effective compared to women who are not participating in the weight loss intervention. Another study carried out in Australia found that half of the participants did not report fertilization despite significant weight loss.
However, 4 out of 10 women achieved only 6% weight loss after only two weeks into the study compared with the 13% weight loss observed in the aforementioned pilot study. The author of the Australian study report that the treatment outcome during IVF was not fully evaluated as the study included only a small sample and that ended in low weight loss results.
Intervention trials on at-risk populations have shown prevention and control of diabetes mellitus and cardiovascular risk factors while weight loss in patients with Type 2 diabetes mellitus is improving glucose metabolism in the long-term.
Nackers et al. showed that moderately to severely obese women who lost weight rapidly, compared with moderate or slow weight loss, did not regain that weight while they also had a more active lifestyle. Given the promising results of this study, we believe that this intervention will be acceptable for women with fertility issues, especially in cases of increased risk of pregnancy-related complications as it may also improve the adverse epigenetic effects of obesity on children born from obese women.
Amy Rothberg et. al.2016. Feasibility of a brief, intensive weight loss intervention to improve reproductive outcomes in obese, subfertile women a pilot study. Fertility and Sterility, Vol. 106, No.5, p.1212-1220.