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Surgery and fertility

Surgery improves fertility in obese women of reproductive age

A prospective study is required to demonstrate that this effect translates into a positive effect on pregnancy outcomes

Bariatric surgery improves factors that underlie fertility and pregnancy outcomes, according to the findings from a study by researchers from the Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK. The paper published in the journal Obesity Surgery, also called for a prospective study to demonstrate that these factors effect translates into a positive effect on pregnancy outcomes.

The aim of the study, 'Bariatric Surgery in Obese Women of Reproductive Age Improves Conditions That Underlie Fertility and Pregnancy Outcomes: Retrospective Cohort Study of UK National Bariatric Surgery Registry (NBSR)’, was to examine the female population of reproductive age having bariatric surgery in the UK, to assess the age and ethnicity of women accessing surgery, and to assess the effect of bariatric surgery on factors that underlie fertility and pregnancy outcomes.

The researchers used data from the UK National Bariatric Surgery Registry (NBSR) for women aged 18–45 years. The NBSR is a comprehensive, prospective, nationwide analysis of outcomes from bariatric surgery in the UK and Ireland. The comorbidities measured include the following: menstrual dysfunction, polycystic ovarian syndrome (PCOS), type 2 diabetes, dyslipidemia, hypertension, asthma, joint pain, functional status, gastro-esophageal reflux, and sleep disorder. Menstrual dysfunction, as defined in the registry, refers to the presence of amenorrhea, irregular periods, or menorrhagia. Functional status in this context refers to exercise tolerance, deemed impaired if the patient is unable to climb a flight of stairs without stopping. 

For comparison to a representative national cohort, data were extracted from the Health Survey for England (HSE), which is an annual national census. Data were collated from 2007 to 2013 inclusive. Women aged 18 to 45 with a BMI ≥40 (representing those who may be considered for bariatric surgery by NICE criteria) were selected.


In total, there were 29,010 male and female patients who underwent bariatric surgery to year 2013, of whom 15,222 were women aged 18 to 45 years old (53 %). Collating the HSE data from 2007 to 2013 produced a total cohort of 91,649 subjects. Female subjects, aged 18–45 years old, with a recorded BMI of ≥40 totaled 384 subjects. The NBSR cohort had a median age of 38 years (IQR 32–42) and was older than the HSE cohort (median 36 years, IQR 30–41; p < 0.0001). Caucasian patients were overrepresented in the NBSR cohort (90% of NBSR vs 84% HSE, p < 0.0001). Bariatric patients were twice as likely to have type 2 diabetes as HSE subjects (14.7% NBSR vs 7.4% HSE, p < 0.0001).

The mean BMI fell in the first year postoperatively from 48.2 ± 8.3 to 37.4 ± 7.5 (p<0.001). Of women with menstrual dysfunction pre-surgery, 12% of patients normalised menstrual function postoperatively. Similarly, of women with PCOS preoperatively, 15 % were classed as no longer having the syndrome postoperatively. Type 2 diabetes showed the greatest improvement with 54% of those patients who had diabetes preoperatively achieving a non-diabetic state postoperatively. The mean total number of comorbidities per patient fell from 2.36 to 0.96 (p<0.05).

Of those with a single comorbidity preoperatively, functional impairment was the most frequent (46%). PCOS was the single comorbidity in only 4 % of these patients and menstrual dysfunction in 8%. However, in patients with three comorbidities, menstrual dysfunction was more commonly seen: 16% had PCOS, and 30% had menstrual dysfunction (Figure 1).

Figure 1: Relative contribution of each comorbidity before and after operation

“This study demonstrates that bariatric surgery is effective at improving factors that may underlie fertility and pregnancy outcomes: body weight, type 2 diabetes, menstrual dysfunction, and PCOS,” the authors write. “Although baseline numbers may be questioned in view of missing data, our results demonstrate improvements in the prevalence of each comorbidity, even after application of sensitivity analyses.”

In addition, they state that the data demonstrate that ethnic minorities are under-represented in the operated population, suggesting reduced access, and requires further investigation to explain possible cultural barriers and to prevent health inequalities in access to services. 

“In summary, over half of all bariatric procedures are carried out on women of reproductive age. At least one in three of these women have menstrual dysfunction at baseline,” the authors conclude. “Bariatric surgery improves factors that underlie fertility and pregnancy outcomes. A prospective study is required to demonstrate that this effect translates into a positive effect on pregnancy outcomes.”

This article was published under the Open Access license.

To access the article, please click here

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