Outcomes of in-vitro fertilization after bariatric surgery: a national register-based case-control study.

STUDY QUESTION: Does previous bariatric surgery (BS) in women affect cumulative live birth rate in IVF? SUMMARY ANSWER: Women having had BS seem to have the same cumulative live birth rate as non-operated women of the same BMI at IVF treatment. WHAT IS KNOWN ALREADY: Because of the perinatal risks of obesity to mother and infant as well as impaired outcomes of IVF, obese women are advised to reduce their weight, but it is not clear whether previous BS could affect IVF results. STUDY DESIGN, SIZE, DURATION: This national register-based case-control study included all cases of BS (n = 30 436) undergoing IVF (n = 153) from 2007 until 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Swedish women between 18 and 45 years operated with BS, with at least one first started cycle of IVF after surgery, were included. For each woman having IVF after BS (n = 153), up to five non-operated control women (n = 744) starting their first IVF cycle during the study period were matched for age, parity and BMI at treatment. The primary outcome in this study was the cumulative live birth rate (CLBR) after the first IVF cycle, defined as all live births after the first cycle including fresh and frozen embryo transfers. MAIN RESULTS AND THE ROLE OF CHANCE: There was no significant difference in CLBR between the BS group and the matched controls (29.4% compared to 33.1%), even though the number of retrieved oocytes (7.6 vs 8.9, P = 0.005) and frozen embryos (1.0 vs 1.5, P = 0.041) were significantly fewer in the BS group. There was no association between cumulative live birth and BS, adjusted odds ratio 1.04, 95% CI (0.73, 1.51). However, the birth weight was significantly lower in the children born to mothers with previous BS, mean (SD) 3190 (690) vs 3478 (729) g, P = 0.037. LIMITATIONS, REASONS FOR CAUTION: Confounders such as age, BMI and previous childbirth were accounted for by the matching design of the study, but there were no data on indication for IVF, anti-Müllerian hormone, smoking or previous comorbidities. The study was exploratory and did not reach sufficient power to detect potential smaller differences in live birth rates. WIDER IMPLICATIONS OF THE FINDINGS: The findings concur with those in previously published smaller studies and provide somewhat reassuring results considering IVF outcomes after BS with a CLBR comparable to that of controls, despite a lower mean birth weight. STUDY FUNDING/COMPETING INTEREST(S): This research was funded by grants from the Southern Health Care Region of Sweden. The authors have no competing interests to declare. TRIAL REGISTRATION NUMBER: N/A.

Impact of diet and bariatric surgery on anti-Müllerian hormone levels.

STUDY QUESTION: Do serum levels of anti-Müllerian hormone (AMH) change in women of reproductive age following dietary and surgery-induced weight loss? SUMMARY ANSWER: AMH levels increased after very low-calorie diet (VLCD) before surgery and decreased at 6 and 12 months after Roux-en-Y gastric bypass (RYGB), beyond expected normal age-related decline. WHAT IS KNOWN ALREADY: Obesity has negative effects on fertility and IVF outcomes, and possibly also on AMH levels. AMH correlates to the number of growing follicles and is used to predict the response to IVF treatment. However, AMH might decrease after bariatric surgery. STUDY DESIGN, SIZE, DURATION: A prospective cohort study of 48 women followed first for 8 weeks preoperatively, then operated with RYGB and followed postoperatively for 1 additional year. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women aged 18-35 years with a mean (SD) BMI 40.9 (3.6) kg/m2 were included at baseline (BL). After the VLCD, a RYGB was performed. Body weight and height were measured at BL and 1 year postoperatively. Hormones were analysed at BL, after VLCD on the day before surgery, and at 6 and 12 months postoperatively. MAIN RESULTS AND THE ROLE OF CHANCE: Median AMH levels were 30.0 pmol/L at BL and rose significantly after VLCD (median: 35.0 pmol/L; P = 0.014). Median AMH at 6 and 12 months postoperatively were significantly lower (19.5 and 18.0 pmol/L, respectively; P = 0.001). Free androgen index (FAI) was significantly lower after 12 months, compared to BL (1.2 vs 3.5, P < 0.0005). LIMITATIONS REASONS FOR CAUTION: Ultrasound for PCOS diagnosis was not performed. The change in laboratory methods for AMH analysis during the study might be a limitation. WIDER IMPLICATIONS OF THE FINDINGS: Obese young women might choose bariatric surgery also for fertility reasons, and the observed decrease in FAI is in line with improved fertility. More research is needed to evaluate the clinical effects of the decrease of AMH, and the effect of bariatric surgery prior to IVF treatment. STUDY FUNDING/COMPETING INTEREST(S): Study-specific laboratory analyses were funded by the Swedish Regional Research Fund (ALF). Authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.