Impact of bariatric surgery on ovarian reserve markers and its correlation with nutritional parameters and adipokines

Abstract

Introduction: A reduction in anti-müllerian hormone (AMH) levels at short-term after bariatric surgery (BS) has been previously described. However, an assessment of ovarian reserve at longer-follow up, and a comprehensive evaluation of the potentially implicated factors has not been reported.

Design: Prospective cohort study.

Materials and methods: Twenty women aged 18-40 years with BMI 43.95 kg/m2 undergoing BS were studied at baseline (BS0), and at 1 month (BS1), 4 months (BS2), 12 months (BS3), and 24-36 months (BS4) after the surgery. Anthropometrics, reproductive hormones (AMH, FSH, LH, estradiol, testosterone, SHBG, androstenedione), metabolic parameters (adiponectin, leptin, ghrelin, insulin), and nutritional blood parameters (markers of nutritional status, vitamins, and minerals) were obtained at each study time point. Antral follicular count (AFC) was assessed by ultrasonography at BS0, BS3, and BS4. Mixed models were used for analysis of longitudinal data.

Results: The mean AMH level was 3.88 ng/mL at BS0, decreased at BS3 (mean= 2.59 ng/mL; p=0.009), and remained stable between BS3 and BS4 (mean= 2.96 ng/mL; p=0.409). We also observed a non-significant decrease in AFC at BS3 (mean=26.14 at BS0, mean 16.81 at BS3; p=0.088) that remained stable at BS4 (mean= 17.86; p=0.731). Mixed models analysis showed: (a) a decrease in 10 kg of body weight was associated with an average decrease of 0.357 ng/mL in AMH (p=0.014); (b) a decrease in 1 BMI point was associated with an average decrease of 0.109 ng/mL in AMH (p=0.005); (c) an increase in 1 µg/mL of adiponectin was associated with an average decrease of 0.091 ng/ml in AMH (p=0.041) Significant positive correlations were found between the AMH levels after BS and plasma concentrations of testosterone, free androgen index, insulin and HOMA index. No significant correlations were detected between AMH levels and nutritional parameters.

Conclusions: Our results were in line with previous observations, showing that AMH levels decreased significantly at 12 months after bariatric surgery, in parallel with a non-significant reduction in AFC. Both ovarian reserve markers showed a later stabilization up to the end of the study. Of note, postoperative AMH levels were positively correlated with key androgen and insulin resistance-related parameters.

Keywords: anti-Müllerian hormone; bariatric surgery; fertility; obesity; ovarian reserve; reproduction.

Figure 1

Boxplot showing anti-Mullerian hormone concentrations (ng/mL) for each time point. Each box represents the middle 50% of the data (25–75% range). The central horizontal line represents the median. Vertical lines represent the 10–90% range of data. Asterisks (*) among bars indicates a statistically significant difference between this point and the baseline status (p< 0.05). NS indicates non-significant differences (p>0.05). BS0, baseline; BS1, 1 month after BS; BS2, 4 months after BS; BS3, 12 months after BS; BS4, 24-36 months after BS; AMH, anti-Mullerian hormone.

Figure 2

Boxplot showing antral follicle count for each time point. Each box represents the middle 50% of the data (25–75% range). The central horizontal line represents the median. Vertical lines represent the 10–90% range of data. NS indicates non-significant differences (p>0.05). BS0, baseline; BS3, 12 months after BS; BS4, 24-36 months after BS; AFC, antral follicle count.

Figure 3

Correlation plot for the associations between biochemical variables at 12 months after BS. The symmetric correlation matrix was created using the R “corrplot” package. The colors represent the degree of pairwise correlation according Pearson’s correlation coefficient. AMH, anti-Mullerian hormone; FAI, free androgen index; SHBG, sex hormone binding globulin; Vit D3, 25-hydroxyvitamin D3; CPR, C-reactive protein.