Main Article Content
obesity, fertility, polycystic ovary syndrome (PCOS), Assisted reproductive technology (ART)
Obesity has been associated with reduced fertility, although the dynamics and mechanisms which link excess weight to reduced fertility are not yet fully clarified. Obese women, especially those with central obesity, are less likely to conceive per cycle. Obese women suffer from perturbations of the hypothalamus-pituitary-ovary axis, disturbances of the menstrual cycle and are up to three times more likely to suffer from oligo/anovulation. A delicate hormonal balance regulates follicular development and the maturation of oocytes and it has been observed that obesity can alter the hormonal environment: adipocytes, in fact, are responsible for the production of a hormone called leptin (present in high quantities in obese women) which has been associated with reduced fecundity. In addition to compromising ovulation, obesity negatively affects the development and implantation of the endometrium. The expression of polycystic ovary syndrome (PCOS) is regulated, in part, by weight, so obese women with PCOS often have a more severe phenotype and higher subfertility rates. Furthermore, obesity impairs women's response to medically assisted procreation (MAP) treatments. The authors have set out to delineate a broad-ranging overview of obesity’s impact on female fertility, by drawing upon sources spanning the 1994-2022 period. Assisted reproductive technology (ART) procedures are also discussed as they relate to obese patients. In addition the dynamics by which maternal obesity reportedly affects fetal, neonatal and child development have also been briefly enunciated.
2.Ricci G, Tomassoni D, Pirillo I, et al. Obesity in the European region: social aspects, epidemiology and preventive strategies. Eur Rev Med Pharmacol Sci 2018; 22: 6930-9.
3.Rich-Edwards JW, Goldman MB, Willett WC, et al. Adolescent body mass index and infertility caused by ovulatory disorder. Am J Obstet Gynecol 1994; 171-7.
4.Gullo G, Carlomagno G, Unfer V, D'Anna R. Myo-inositol: from induction of ovulation to menopausal disorder management. Minerva Ginecologica 2015; 67: 485-6.
5.Bezerra Espinola MS, Laganà AS, Bilotta G, Gullo G, Aragona C, Unfer V. D-chiro-inositol Induces Ovulation in Non-Polycystic Ovary Syndrome (PCOS), Non-Insulin-Resistant Young Women, Likely by Modulating Aromatase Expression: A Report of 2 Cases. Am J Case Rep. 2021; 22: e932722.
6.D'Anna R, Corrado F, Loddo S, Gullo G, Giunta L, Di Benedetto A. Myoinositol plus α-lactalbumin supplementation, insulin resistance and birth outcomes in women with gestational diabetes mellitus: a randomized, controlled study. Sci Rep 2021; 11: 8866.
7.D'Anna R, Santamaria A, Giorgianni G, et al. Myo-inositol and melatonin in the menopausaltransition. Gynecol Endocrinol 2017; 33: 279-82.
8.Tamer Erel C, Senturk LM. The impact of body mass index on assisted reproduction. Curr Opin Obstet Gynecol 2009; 21: 228-35.
9.Grodstein F, Goldman MB, Cramer DW. Body mass index and ovulatory infertility. Epidemiology 1994; 5: 247-50.
10.Hassan MA, Killick SR. Negative lifestyle is associated with a significant reduction in fecundity. Fertil Steril 2004; 81: 384-92.
11.Zaadstra BM, Seidell JC, Van Noord PA, et al. Fat and female fecundity: prospective study of effect of body fat distribution on conception rates. BMJ 1993; 306: 484-7.
12.Hartz AJ, Barboriak PN, Wong A, Katayama KP, Rimm AA. The association of obesity with infertility and related menstural abnormalities in women. Int J Obes 1979; 3:57–73.
13.Gesink Law DC, Maclehose RF, Longnecker MP. Obesity and time to pregnancy. Hum Reprod 2007; 22: 414-20.
14.Metwally M, Ong KJ, Ledger WL, Li TC. Does high body mass index increase the risk of miscarriage after spontaneous and assisted conception? A meta-analysis of the evidence. Fertil Steril 2008; 90: 714-26.
15.Hamilton-Fairley D, Kiddy D, Watson H, Paterson C, Franks S. Association of moderate obesity with a poor pregnancy outcome in women with polycystic ovary syndrome treated with low dose gonadotrophin. Br J Obstet Gynaecol 1992; 99: 128-31.
16.Fedorcsak P, Dale PO, Storeng R, et al. Impact of overweight and underweight on assisted reproduction treatment. Hum Reprod 2004; 19: 2523-8.
17.Maheshwari A, Stofberg L, Bhattacharya S. Effect of overweight and obesity on assisted reproductive technology – a systematic review. Hum Reprod Update 2007; 13: 433-44.
18.Candeloro M, Di Nisio M, Ponzano A, et al. Effects of Obesity and Thrombophilia on the Risk of Abortion in Women Undergoing In Vitro Fertilization. Front Endocrinol (Lausanne) 2020; 11: 594867.
19.Setton R, Chung A, Zimmerman L, Melnick A, Rosenwaks Z, Spandorfer SD. Body mass index is not associated with donor oocyte recipient success: an ideal study using a paired analysis of sibling-oocytes. F S Rep 2020; 1: 25-29.
20.Abdulkhalikova D, Sustarsic A, Vrtačnik Bokal E, Jancar N, Jensterle M, Burnik Papler T. The Lifestyle Modifications and Endometrial Proteome Changes of Women With Polycystic Ovary Syndrome and Obesity. Front Endocrinol (Lausanne) 2022; 13: 888460.
21.Zeng X, Pang H, Li X, Luo S, Jin S, Li S. Impact of obesity on endometrial blood flow in women without polycystic ovarian syndrome during intracytoplasmic sperm injection. Reprod Biol Endocrinol 2013; 11: 57.
22.Dabbagh Rezaeiyeh R, Mehrara A, Mohammad Ali Pour A, Fallahi J, Forouhari S. Impact of Various Parameters as Predictors of The Success Rate of In Vitro Fertilization. Int J Fertil Steril 2022; 16: 76-84.
23.van Swieten EC, van der Leeuw-Harmsen L, Badings EA, van der Linden PJ. Obesity and clomiphene challenge test as predictors of outcome of in vitro fertilization and intracytoplasmic sperm injection. Gynecol Obstet Invest 2005; 59: 220-4.
24.Gullo G, Petousis S, Papatheodorou A, et al. Closed vs. Open Oocyte Vitrification Methods Are Equally Effective for Blastocyst Embryo Transfers: Prospective Study from a Sibling Oocyte Donation Program. Gynecol Obstet Invest 2020; 85: 206-12.
25.Prapas Y, Ravanos K, Petousis S, et al. GnRH antagonist administered twice the day before hCG trigger combined with a step-down protocol may prevent OHSS in IVF/ICSI antagonist cycles at risk for OHSS without affecting the reproductive outcomes: a prospective randomized control trial. J Assist Reprod Genet 2017; 34: 1537-45.
26.Capozzi VA, Rosati A, Rumolo V, et al. Novelties of ultrasound imaging for endometrial cancer preoperative workup. Minerva Med 2021; 112: 3-11.
27.Gullo G, Etrusco A, Cucinella G, et al. Fertility-Sparing Approach in Women Affected by Stage I and Low-Grade Endometrial Carcinoma: An Updated Overview. Int J Mol Sci 2021; 22: 11825.
28.Andress J, Pasternak J, Walter C, Kommoss S, Krämer B, Hartkopf A, Brucker SY, Schönfisch B, Steinmacher S. Fertility preserving management of early endometrial cancer in a patient cohort at the department of women's health at the university of Tuebingen. Arch Gynecol Obstet 2021; 304: 215-221.
29.Prapas Y, Petousis S, Panagiotidis Y, et al. Injection of embryo culture supernatant to the endometrial cavity does not affect outcomes in IVF/ICSI or oocyte donation cycles: a randomized clinical trial. Eur J Obstet Gynecol Reprod Biol 2012; 162: 169-73.
30.Campisciano G, de Manzini N, Delbue S, et al. The Obesity-Related Gut Bacterial and Viral Dysbiosis Can Impact the Risk of Colon Cancer Development. Microorganisms 2020; 8: 431.
31.Bartolacci A, Buratini J, Moutier C, et al. Maternal body mass index affects embryo morphokinetics: a time-lapse study. J Assist Reprod Genet 2019; 36: 1109-1116.
32.Wang Y, Wang Y. Accelerated Ovarian Aging Among Type 2 Diabetes Patients and Its Association With Adverse Lipid Profile. Front Endocrinol (Lausanne) 2022; 13: 780979.
33.Chen R, Chen L, Liu Y, et al. Association of parental prepregnancy BMI with neonatal outcomes and birth defect in fresh embryo transfer cycles: a retrospective cohort study. BMC Pregnancy Childbirth 2021; 21: 793.
34.Alizadeh A, Omani-Samani R, Mansournia MA, Akbari Sene A, Rahimi Foroushani A. Causal Effects of Body Mass Index and Maternal Age on Oocyte Maturation in Assisted Reproductive Technology: Model-Average Causal Effect and Bayesian LASSO Method. Iran J Public Health 2020; 49: 2161-2169.
35.Gullo G, Cucinella G, Perino A, et al. The Gender Gap in the Diagnostic-Therapeutic Journey of the Infertile Couple. Int J Environ Res Public Health 2021; 18: 6184.
36.Buzzaccarini G, Vitagliano A, Busnelli A, et al. Perceived Elementary Grid (PEG) proposal for dyadic coping evaluation in the infertile couple during assisted reproductive treatments. Clin Exp Obstet Gynecol 2022; 49: 40.
37.Burgio S, Polizzi C, Buzzaccarini G, et al. Psychological variables in medically assisted reproduction: a systematic review. Prz Menopauzalny 2022; 21: 47-63.
38.García-Ferreyra J, Carpio J, Zambrano M, Valdivieso-Mejía P, Valdivieso-Rivera P. Overweight and obesity significantly reduce pregnancy, implantation, and live birth rates in women undergoing In Vitro Fertilization procedures. JBRA Assist Reprod 2021; 25: 394-402.
39.Tang K, Guo Y, Wu L, Luo Y, Gong B, Feng L. A non-linear dose-response relation of female body mass index and in vitro fertilization outcomes. J Assist Reprod Genet 2021; 38: 931-939.
40.Casu G, Zaia V, Montagna E, et al. The Infertility-Related Stress Scale: Validation of a Brazilian-Portuguese Version and Measurement Invariance Across Brazil and Italy. Front Psychol 2022; 12: 784222.
41.Mandelbaum RS, Bainvoll L, Violette CJ, et al. The influence of obesity on incidence of complications in patients hospitalized with ovarian hyperstimulation syndrome. Arch Gynecol Obstet 2022; 305: 483-493.
42.Guan HJ, Pan LQ, Song H, Tang HY, Tang LS. Predictors of pregnancy after intrauterine insemination in women with polycystic ovary syndrome. J Int Med Res 2021; 49: 3000605211018600.
43.Snider AP, Wood JR. Obesity induces ovarian inflammation and reduces oocyte quality. Reproduction. 2019; 158: R79-R90.
44.Kochar Kaur K. An update of impact of obesity on female infertility and its management. IPCB 2018;4.;
45.Barbe A, Bongrani A, Mellouk N, Estienne A, Kurowska P, Grandhaye J, Elfassy Y, Levy R, Rak A, Froment P, Dupont J. Mechanisms of Adiponectin Action in Fertility: An Overview from Gametogenesis to Gestation in Humans and Animal Models in Normal and Pathological Conditions. Int J Mol Sci 2019; 20: 1526.
46.Ruebel ML, Cotter M, Sims CR, Moutos DM, Badger TM, Cleves MA, Shankar K, Andres A. Obesity Modulates Inflammation and Lipid Metabolism Oocyte Gene Expression: A Single-Cell Transcriptome Perspective. J Clin Endocrinol Metab 2017; 102: 2029-2038.
47.Silvestris E, de Pergola G, Rosania R, Loverro G. Obesity as disruptor of the female fertility. Reprod Biol Endocrinol 2018; 16: 22.
48.Broughton DE, Moley KH. Obesity and female infertility: potential mediators of obesity's impact. Fertil Steril 2017; 107: 840-847.
49.Eastman AJ, Moore RE, Townsend SD, Gaddy JA, Aronoff DM. The Influence of Obesity and Associated Fatty Acids on Placental Inflammation. Clin Ther 2021; 43: 265-278.
50.Callaway LK, Prins JB, Chang AM, McIntyre HD. The prevalence and impact of overweight and obesity in an Australian Obstetric population. Med J Aust 2006; 184: 56-9.
51.Ruofan Y, Goetzinger KR, Crimmins S, Kopelman JN, Contag SA. Association of Maternal Obesity With Maternal and Neonatal Outcomes in Cases of Uterine Rupture. Obstet Gynecol 2017; 129: 683-8.
52.Poston L, Caleyachetty R, Cnattingius S, et al. Preconceptional and maternal obesity: epidemiology and health consequences. Lancet Diabetes Endocrinol 2016; 4: 1025-36.
53.Alsheef MA, Alabbad AM, Albassam RA, et al. Pregnancy and Venous Thromboembolism: Risk Factors, Trends, Management, and Mortality. Biomed Res Int 2020; 2020: 4071892.
54.Main EK, McCain CL, Morton CH, Holtby S, Lawton ES. Pregnancy-Related Mortality in California. Obstet Gynecol 2015; 125: 938-47.
55.Malvasi A, Zaami S, Tinelli A, Trojano G, Montanari Vergallo G, Marinelli E. Kristeller maneuvers or fundal pressure and maternal/neonatal morbidity: obstetric and judicial literature review. J Matern Fetal Neonatal Med 2019; 32: 2598-607.
56.Frati P, Foldes-Papp Z, Zaami S, Busardo FP. Amniotic fluid embolism: what level of scientific evidence can be drawn? A systematic review. Curr Pharm Biotechnol 2014; 14: 1157-62.
57.Watkins ML, Rasmussen SA, Honein MA, Botto LD, Moore CA. Maternal obesity and risk for birth defects. Pediatrics 2003; 111: 1152-8.
58.McAuliffe FM, Killeen SL, Jacob CM, et al. Management of prepregnancy, pregnancy, and postpartum obesity from the FIGO Pregnancy and Non-Communicable Diseases Committee: A FIGO (International Federation of Gynecology and Obstetrics) guideline. Int J Gynaecol Obstet 2020; 151:16-36.
59.Baldini D, Beck R, Negro F, De Viti D. Assisted reproductive technologies and metabolic syndrome complications: medico-legal reappraisal. Clin Ter 2019; 170: e364-e367.
60.Golden A. Obesity's Impact. Nurs Clin North Am 2021; 56: xiii-xiv.
61.Harrison S, Dixon P, Jones HE, Davies AR, Howe LD, Davies NM. Long-term cost-effectiveness of interventions for obesity: A mendelian randomisation study. PLoS Med 2021; 18: e1003725.
62.Greer AG, Butler Ryckeley J. Ethics of Obesity Legislation and Litigation: A Public Health Policy Debate. Bariat Nurs Surg Pat 2011; 6: 173-7.
63.Best D, Avenell A, Bhattacharya S, Stadler G. New debate: is it time for infertility weight-loss programmes to be couple-based? Hum Reprod 2017; 32: 2359-2365.
64.Gaillard R. Maternal obesity during pregnancy and cardiovascular development and disease in the offspring. Eur J Epidemiol. 2015;30:1141–1152.
65.Ferretti G, Cester AM, Bacchetti T, et al. Leptin and paraoxonase activity in cord blood from obese mothers. J Matern Fetal Neonatal Med 2014;27:1353–1356.
66.Gaillard R, Steegers EA, Duijts L, et al. Childhood cardiometabolic outcomes of maternal obesity during pregnancy: the Generation R Study. Hypertension 2014; 63: 683–691.
67.Yu Z, Han S, Zhu J, et al. Prepregnancy body mass index in relation to infant birth weight and offspring overweight/obesity: a systematic review and meta-analysis. PLoS One 2013; 8: e61627.
68.Alfaradhi MZ, Fernandez-Twinn DS, Martin-Gronert MS, et al. Oxidative stress and altered lipid homeostasis in the programming of offspring fatty liver by maternal obesity. Am J Physiol Regul Integr Comp Physiol 2014; 307: R26–R34.
69.Martin-Gronert MS, Fernandez-Twinn DS, Poston L, Ozanne SE. Altered hepatic insulin signalling in male offspring of obese mice. J Dev Orig Health Dis 2010; 1: 184–191.
70.Ricci G, Pirillo I, Tomassoni D, Sirignano A, Grappasonni I. Metabolic syndrome, hypertension, and nervous system injury: Epidemiological correlates. Clin Exp Hypertens 2017; 39: 8-16.
71.Chandrasekaran S, Neal-Perry G. Long-term consequences of obesity on female fertility and the health of the offspring. Curr Opin Obstet Gynecol. 2017; 29: 180-187.
72.Pan L, Li X, Feng Y, Hong L. Psychological assessment of children and adolescents with obesity. J Int Med Res 2018; 46: 89-97.
73.Cawley J, Biener A, Meyerhoefer C, Ding Y, Zvenyach T, Smolarz BG, Ramasamy A. Direct medical costs of obesity in the United States and the most populous states. J Manag Care Spec Pharm 2021; 27: 354-366.
74.Tourangeau K, Nord C, Lê T, Sorongon AG, Najarian M. (2009). Early Childhood Longitudinal Study, Kindergarten Class of 1998–99 (ECLS-K), Combined User’s Manual for the ECLS-K Eighth-Grade and K–8 Full Sample Data Files and Electronic Codebooks (NCES 2009–004). National Center for Education Statistics, Institute of Education Sciences, U.S. Department of Education. Washington, DC.
75.Lee EY, Yoon KH. Epidemic obesity in children and adolescents: risk factors and prevention. Front Med 2018; 12: 658-666.
76.Kim CH, Lee SH. Effectiveness of Lifestyle Modification in Polycystic Ovary Syndrome Patients with Obesity: A Systematic Review and Meta-Analysis. Life (Basel) 2022; 12: 308.
77.Eskew AM, Bedrick BS, Chavarro JE, Riley JK, Jungheim ES. Dietary patterns are associated with improved ovarian reserve in overweight and obese women: a cross-sectional study of the Lifestyle and Ovarian Reserve (LORe) cohort. Reprod Biol Endocrinol 2022; 20: 33.
78.Belan M, Gélinas M, Carranza-Mamane B, et al. Protocol of the Fit-For-Fertility study: a multicentre randomised controlled trial assessing a lifestyle programme targeting women with obesity and infertility. BMJ Open 2022; 12: e061554.
79.Valent AM, Hall ES, DeFranco EA. The influence of obesity on perinatal outcomes in pregnancies achieved with assisted reproductive technology: A population-based retrospective cohort study. Obstet Med 2016; 9: 34-9.
80.Maheshwari A, Stofberg L, Bhattacharya S. Effect of overweight and obesity on assisted reproductive technology – a systematic review. Hum Reprod Update 2007; 13: 433-44.
81.Amiri M, Ramezani Tehrani F. Potential Adverse Effects of Female and Male Obesity on Fertility: A Narrative Review. Int J Endocrinol Metab 2020; 18: e101776.
82.Sheng Y, Lu G, Liu J, et al. Effect of body mass index on the outcomes of controlled ovarian hyperstimulation in Chinese women with polycystic ovary syndrome: a multicenter, prospective, observational study. J Assist Reprod Genet 2017; 34: 61-70.
83.Lashen H, Ledger W, Bernal AL, Barlow D. Extremes of body mass do not adversely affect the outcome of superovulation and in vitro fertilization. Hum Reprod 1999; 14: 712-5.
84.Martinuzzi K, Ryan S, Luna M, Copperman AB. Elevated body mass index (BMI) does not adversely affect in vitro fertilization outcome in young women. J Assist Reprod Genet 2008; 25: 169-75.
85.Fridstrom M, Sjoblom P, Pousette A, Hillensjo T. Serem FSH levels in women with polycystic ovary syndrome during ovulation induction using down-regulation and urofollitropin. Eur J Endocrinol 1997; 136: 488-92.
86.Bellver J, Busso C, Pellicer A, Remohi J, Simon C. Obesity and assisted reproductive technology outcomes. Reprod Biomed Online 2006; 12: 562-8.
87.Balen AH, Anderson RA; Policy & Practice Committee of the BFS. Impact of obesity on female reproductive health: British Fertility Society, Policy and Practice Guidelines. Hum Fertil (Camb) 2007; 10: 195-206.
88.Wass P, Waldenstrom U, Rossner S, Hellberg D. An android body fat distribution in females impairs the pregnancy rate of in-vitro fertilization-embryo transfer. Hum Reprod 1997; 12: 2057-60.
89.Belan M, Harnois-Leblanc S, Laferrère B, Baillargeon JP. Optimizing reproductive health in women with obesity and infertility. CMAJ 2018; 190: E742-E745.
90.Ferlitsch K, Sator MO, Gruber DM, Rucklinger E, Gruber CJ, Huber JC. Body mass index, follicle-stimulating hormone and their predictive value in in vitro fertilization. J Assist Reprod Genet 2004; 21: 431-6.
91.Calhaz-Jorge C, De Geyter CH, Kupka MS, et al. Survey on ART and IUI: legislation, regulation, funding and registries in European countries: The European IVF-monitoring Consortium (EIM) for the European Society of Human Reproduction and Embryology (ESHRE). Hum Reprod Open 2020; 2020: hoz044.
92.Guggenheim BL. France Tackles Reproductive Rights, Launching a Series of Reforms. South EU Summit. Issued on 2nd July 2019. Available at: https://southeusum-mit.com/europe/france/france-tackles-reproductive-rights-launching-a-series-of-reforms/ (Accessed on 31th March 2022).
93.Montanari Vergallo G, Zaami S, Bruti V, Signore F, Marinelli E. How the Legislation on Medically Assisted Procreation Has Evolved in Italy. Med Law. 2017; 36: 5-28.
94.Harper J, Geraedts J, Borry P, et al. Current issues in medically assisted reproduction and genetics in Europe: research, clinical practice, ethics, legal issues and policy. Hum Reprod 2014; 29: 1603-9.
95.Zaami S, Del Rio A, Negro F, Varone MC, Marinelli S, Montanari Vergallo G. The March 2021 Italian constitutional court ruling on surrogacy: a prelude to common European legislation for the sake of reproductive health? Eur J Contracept Reprod Health Care 2022; 27: 61-6.
96.Negro F, Marinelli S. Is there anything left of the Italian law governing medically-assisted procreation. Clin Ter 2021; 172: 57-9.
97.Piersanti V, Consalvo F, Signore F, Del Rio A, Zaami S. Surrogacy and “Procreative Tourism”. What Does the Future Hold from the Ethical and Legal Perspectives?. Medicina (Kaunas) 2021; 57: 47.
98.Bhakuni H, Miotto L. Conscientious objection to abortion in the developing world: The correspondence argument. Dev World Bioeth 2021; 21: 90-95.
99.Montanari Vergallo G, Zaami S, Di Luca NM, Marinelli E. The conscientious objection: debate on emergency contraception. Clin Ter 2017; 168: e113-e119.
100.Ricci G, Campanozzi LL, Marinelli S, Midolo E, Ruggeri L. The human embryo, subjectivity and legal capacity. Notes in the light of art. 1 of the Italian law on "medically assisted procreation". Clin Ter 2019; 170: e102-e107.
101.Pashkov V, Lyfar A. Assisted reproductive technologies: the problems of legal enforcement. Wiad Lek 2018; 71: 1066-1070.
102.Montanari Vergallo G, Marinelli E, di Luca NM, Zaami S. Gamete Donation: Are Children Entitled to Know Their Genetic Origins? A Comparison of Opposing Views. The Italian State of Affairs. Eur J Health Law 2018; 25: 322-37.
103.Delbon P, Conti A. Medically Assisted Procreation and Fast-Moving Developments in Science and Law: Ethical and Legal Issues in Heterologous Procreation in Italy. JJ Public Health Res 2015; 4: 554.
104.Zaami S. Assisted heterologous fertilization and the right of donorconceived children to know their biological origins. Clin Ter 2018; 169: e39-e43.
105.Statement from British Fertility Society (BFS) and Association of Reproductive Clinical Scientists (ARCS). Available online: https://www.britishfertilitysociety.org.uk/2020/03/30/statement-from-british-fertility-society-and-association-of-reproductive-and-clinical-scientists-for-fertility-staff/ (Accessed on 17April 2022).
106.Armocida B, Formenti B, Ussai S, Palestra F, Missoni E. The Italian health system and the COVID-19 challenge. Lancet Public Health 2020; 5: e253.
107.Rallo G, Negro F, Consalvo F, Piersanti V, Marinelli S. Medically assisted procreation in times of COVID-19: what impact on health care system organization and the reproductive rights of couples? Acta Biomed 2021; 92: e2021275.
108.Balen AH, Anderson RA. Policy & Practice Committee of the BFS. Impact of obesity on female reproductive health: British Fertility Society, Policy and Practice Guidelines. Hum Fertil (Camb) 2007; 10: 195-206.
109.Brauer P, Gorber SC, Shaw E, Singh H, Bell N, Shane ARE, Jaramillo A, Tonelli M; Canadian Task Force on Preventive Health Care. Recommendations for prevention of weight gain and use of behavioural and pharmacologic interventions to manage overweight and obesity in adults in primary care. CMAJ 2015; 187: 184-195.
110.Practice Committee of the American Society for Reproductive Medicine. Obesity and reproduction: a committee opinion. Fertil Steril 2015; 104: 1116-26.