Hormonal contraceptives for contraception in overweight or obese women

Cochrane Database of Systematic Reviews

Volumn 2016, Issue 8, 2016, Pages

  Lopez, Laureen M ^a   Bernholc, Alissa ^a   Chen, Mario ^a   Grey, Thomas W ^a   Otterness, Conrad ^b   Westhoff, Carolyn ^c   Edelman, Alison ^d   Helmerhorst, Frans M ^e  

^a FAMILY HEALTH INTERNATIONAL   (United States)

^b Tak   (Thailand)

^c Och Spine at New York Presbyterian Hospitals   (United States)

^d OREGON HEALTH AND SCIENCE UNIVERSITY   (United States)

^e LEIDEN UNIVERSITY MEDICAL CENTER   (Netherlands)

Author keywords

[No Author keywords available]

Indexed keywords

CONTRACEPTIVE AGENT; DESOGESTREL; DROSPIRENONE; ETHINYLESTRADIOL; ETONOGESTREL; GESTAGEN; LEVONORGESTREL; MEDROXYPROGESTERONE ACETATE; NOMEGESTROL ACETATE; NORELGESTROMIN; NORETHISTERONE; NORETHISTERONE ACETATE; NORGESTIMATE; ORAL CONTRACEPTIVE AGENT;

BIRTH CONTROL; BODY COMPOSITION; BODY MASS; CONTRACEPTION; CONTRACEPTIVE PATCH; DRUG EFFICACY; FEMALE; HUMAN; INTRAUTERINE CONTRACEPTIVE DEVICE; OBESITY; PREGNANCY; PREGNANCY RATE; PRIORITY JOURNAL; REVIEW; SYSTEMATIC REVIEW; TRANSDERMAL PATCH; VAGINA RING; BODY WEIGHT; META ANALYSIS; PROCEDURES; PROSPECTIVE STUDY; RANDOMIZED CONTROLLED TRIAL (TOPIC); UNPLANNED PREGNANCY;

BODY MASS INDEX; BODY WEIGHT; CONTRACEPTION; CONTRACEPTIVE AGENTS, FEMALE; FEMALE; HUMANS; OBESITY; OVERWEIGHT; PREGNANCY; PREGNANCY RATE; PREGNANCY, UNPLANNED; PROSPECTIVE STUDIES; RANDOMIZED CONTROLLED TRIALS AS TOPIC;

EID: 84982214183     PISSN: None     EISSN: 1469493X     Source Type: Journal    
DOI: 10.1002/14651858.CD008452.pub4     Document Type: Review

References (96)

1. Burkman RT, Fisher AC, Wan GJ, Barnowski CE, LaGuardia KD. Association between efficacy and body weight or body mass index for two low-dose oral contraceptives. Contraception 2009;79(6):424-7.
2. Hampton RM, Short M, Bieber E, Bouchard C, Ayotte N, et al. Comparison of a novel norgestimate/ethinyl estradiol oral contraceptive (Ortho Tri-Cyclen Lo) with the oral contraceptive Loestrin Fe 1/20. Contraception 2001;63(6):289-95.
3. Hampton RM, Zhang HF, Barnowski C, Wan GJ. Bleeding patterns with monophasic and triphasic low-dose ethinyl estradiol combined oral contraceptives. Contraception 2008;77(6):415-9.
4. Zhang H, LaGuardia K, Creanga D. Higher body weight and body mass index are not associated with reduced efficacy in Ortho Tri-Cyclen Lo users (abstract). Obstetrics and Gynecology 2006;107(4 Suppl):50S.
5. Gemzell-Danielsson K, Apter D, Hauck B, Schmelter T, Rybowski S, Rosen K, et al. The effect of age, parity and body mass index on the efficacy, safety, placement and user satisfaction associated with two low-dose levonorgestrel intrauterine contraceptive Systems: subgroup analyses of data from a Phase III trial. PloS Pne 2015;10(9):e0135309.
6. Kaunitz AM, Dermout S, Tuppurainen M, Jensen J, Rosen K, Gemzell-Danielsson K. Efficacy and safety of two low-dose levonorgestrel intrauterine systems according to women's age: a global, multicentre, open-label, randomized 3-year Phase III Pearl Index study (conference poster abstract). European Journal of Contraception and Reproductive Health Care 2013;18(S1):S191-2.
7. Nelson A, Apter D, Hauck B, Schmelter T, Rybowski S, Rosen K, et al. Two low-dose levonorgestrel intrauterine contraceptive systems. Obstetrics and Gynecology 2013;122(6):1205-13.
8. Grubb GS, Moore D, Anderson NG. Pre-introductory clinical trials of Norplant implants: a comparison of seventeen countries' experience. Contraception 1995;52(5):287-96.
9. Gu S, Sivin I, Du M, Zhang L, Ying L, Meng F, et al. Effectiveness of Norplant implants through seven years: a large-scale study in China. Contraception 1995;52(2):99-103.
10. Gu SJ, Du MK, Zhang LD, Liu YL, Wang SH, Sivin I. A 5-year evaluation of NORPLANT contraceptive implants in China. Obstetrics and Gynecology 1994;83(5 Pt 1):673-8.
11. Jain J, Jakimiuk AJ, Bode FR, Ross D, Kaunitz AM. Contraceptive efficacy and safety of DMPA-SC. Contraception 2004;70(4):269-75.
12. Kaunitz AM, Archer DF, Mishell DR Jr, Foegh M. Safety and tolerability of a new low-dose contraceptive patch in obese and nonobese women. American Journal of Obstetrics and Gynecology 2015;212(3):318.e1-8.
13. Kaunitz AM, Portman D, Westhoff CL, Archer DF, Mishell DR Jr, Foegh M. Self-reported and verified compliance in a phase 3 clinical trial of a novel low-dose contraceptive patch and pill. Contraception 2015;91(3):204-10.
14. Kaunitz AM, Portman D, Westhoff CL, Archer DF, Mishell DR Jr, Rubin A, et al. Low-dose levonorgestrel and ethinyl estradiol patch and pill: a randomized controlled trial. Obstetrics and Gynecology 2014;123(2 Pt 1):295-303.
15. Mansour D, Sundstrom Poromaa I, Sommer W, Korver T. Effect of body mass index and age on the contraceptive effectiveness of nomegestrol acetate/17beta-oestradiol and drospirenone/ethinylestradiol. European Journal of Contraception and Reproductive Health Care 2012; Vol. 17, issue Suppl 1:S95.
16. Mansour D, Verhoeven C, Sommer W, Weisberg E, Taneepanichskul S, Melis GB, et al. Efficacy and tolerability of a monophasic combined oral contraceptive containing nomegestrol acetate and 17β-oestradiol in a 24/4 regimen, in comparison to an oral contraceptive containing ethinylestradiol and drospirenone in a 21/7 regimen. European Journal of Contraception and Reproductive Health Care. 2011/10/15 2011; Vol. 16, issue 6:430-43.
17. Archer DF, Nakajima ST, Sawyer AT, Wentworth J, Trupin S, Koltun WD, et al. Norethindrone acetate 1.0 milligram and ethinyl estradiol 10 micrograms as an ultra low-dose oral contraceptive. Obstetrics and Gynecology 2013;122(3):601-7.
18. Nakajima ST, Pappadakis J, Archer DF. Body mass index does not affect the efficacy or bleeding profile during use of an ultra-low-dose combined oral contraceptive. Contraception 2016;93(1):52-7.
19. Sivin I, Lahteenmaki P, Ranta S, Darney P, Klaisle C, Wan L, et al. Levonorgestrel concentrations during use of levonorgestrel rod (LNG ROD) implants. Contraception 1997;55(2):81-5.
20. Sivin I, Wan L, Ranta S, Alvarez F, Brache V, Mishell DR, et al. Levonorgestrel concentrations during 7 years of continuous use of Jadelle contraceptive implants. Contraception 2001;64(1):43-9.
21. Sivin I, Alvarez F, Mishell D R Jr, Darney P, Wan L, Brache V, et al. Contraception with two levonorgestrel rod implants. A 5-year study in the United States and Dominican Republic. Contraception 1998;58(5):275-82.
22. Sivin I, Campodonico I, Kiriwat O, Holma P, Diaz S, Wan L, et al. The performance of levonorgestrel rod and Norplant contraceptive implants: a 5 year randomized study. Human Reproduction 1998;13(12):3371-8.
23. Sivin I, Viegas O, Campodonico I, Diaz S, Pavez M, Wan L, et al. Clinical performance of a new two-rod levonorgestrel contraceptive implant: a three-year randomized study with Norplant implants as controls. Contraception 1997;55(2):73-80.
24. Sivin I, Mishell DR Jr, Darney P, Wan L, Christ M. Levonorgestrel capsule implants in the United States: a 5-year study. Obstetrics and Gynecology 1998;92(3):337-44.
25. Kroll R, Reape KZ, Margolis M. The efficacy and safety of a low-dose, 91-day, extended-regimen oral contraceptive with continuous ethinyl estradiol. Contraception 2010;81(1):41-8.
26. Westhoff CL, Hait HI, Reape KZ. Body weight does not impact pregnancy rates during use of a low-dose extended-regimen 91-day oral contraceptive. Contraception. 2011/11/10 2012; Vol. 85, issue 3:235-9.
27. World Health Organization, Task Force on Long-Acting Systemic Agents for Fertility Regulation. Microdose intravaginal levonorgestrel contraception: a multicentre clinical trial. I. Contraceptive efficacy and side effects. Contraception 1990;41(2):105-24.
28. World Health Organization, Task Force on Long-Acting Systemic Agents for Fertility Regulation. Microdose intravaginal levonorgestrel contraception: a multicentre clinical trial. II. Expulsions and removals. Contraception 1990;41(2):125-41.
29. World Health Organization, Task Force on Long-Acting Systemic Agents for Fertility Regulation. Microdose intravaginal levonorgestrel contraception: a multicentre clinical trial. III. The relationship between pregnancy rate and body weight. World Health Organization. Contraception 1990;41(2):143-50.
30. Secura GM, Allsworth JE, Madden T, Mullersman JL, Peipert JF. The Contraceptive CHOICE Project: reducing barriers to long-acting reversible contraception. American Journal of Obstetrics and Gynecology. 2010/06/15 2010; Vol. 203, issue 2:115 e1-7.
31. Xu H, Wade JA, Peipert JF, Zhao Q, Madden T, Secura GM. Contraceptive failure rates of etonogestrel subdermal implants in overweight and obese women. Obstetrics and Gynecology. 2012/06/09 2012; Vol. 120, issue 1:21-6.
32. Yamazaki M, Dwyer K, Sohban M, Davis D, Kim MJ, Soule L, et al. Effect of obesity on the effectiveness of hormonal contraceptives: an individual participant data meta-analysis. Contraception 2015 Aug 4 [Epub ahead of print].
33. Audet MC, Moreau M, Koltun WD, Waldbaum AS, Shangold G, Fisher AC, et al. Evaluation of contraceptive efficacy and cycle control of a transdermal contraceptive patch vs an oral contraceptive: a randomized controlled trial. Journal of the American Medical Association 2001;285(18):2347-54.
34. Smallwood GH, Meador ML, Lenihan JP, Shangold GA, Fisher AC, Creasy GW. Efficacy and safety of a transdermal contraceptive system. Obstetrics and Gynecology 2001;98(5 Pt 1):799-805.
35. Urdl W, Apter D, Alperstein A, Koll P, Schonian S, Bringer J, et al. Contraceptive efficacy, compliance and beyond: factors related to satisfaction with once-weekly transdermal compared with oral contraception. European Journal of Obstetrics & Gynecology and Reproductive Biology 2005;121(2):202-10.
36. Zieman M, Guillebaud J, Weisberg E, Shangold GA, Fisher AC, Creasy GW. Contraceptive efficacy and cycle control with the Ortho Evra/Evra transdermal system: the analysis of pooled data. Fertility and Sterility 2002;77(2 Suppl 2):S13-8.
37. Banerjee SK, Baweja R, Bhatt RV, Chatterjee A, Choudhury SD, Coyaji B, et al. Comparative evaluation of contraceptive efficacy of norethisterone oenanthate (200 mg) injectable contraceptive given every two or three monthly. Indian Council of Medical Research Task Force on Hormonal Contraception. Contraception 1984, issue 6:561-74.
38. Berenson AB, van den Berg P, Williams KJ, Rahman M. Effect of injectable and oral contraceptives on glucose and insulin levels. Obstet Gynecol. 2010/12/22 2011; Vol. 117, issue 1:41-7.
39. Casey PM, Long ME, Marnach ML, Bury JE. Bleeding related to etonogestrel subdermal implant in a US population. Contraception. 2011/04/12 2011; Vol. 83, issue 5:426-30. [1879-0518: (Electronic); ]
40. Cirkel U, Schneider HPG. [Incidence of side effects caused by a three-stage preparation administered to 10, 034 women] [[Nebenwirkungsinzidenz eines Dreistufenpräparates unter der Anwendung bei 10.034 Frauen]]. Geburtshilfe und Frauenheilkunde 1991;50(12):969-73.
41. Du MK, Chow LP, Zheng HM, Chen CH. A 10-year follow-up study of contraceptive Norplant implants. International Journal of Gynaecology & Obstetrics. 2000/03/04 2000; Vol. 68, issue 3:249-56.
42. Du MK, Zheng HM, Chen HC, Chow LP. Study of Norplant implants in Shanghai: three-year experience. International Journal of Gynaecology & Obstetrics. 1990/12/01 1990; Vol. 33, issue 4:345-57.
43. Gemzell-Danielsson K, Kardos L, von Hertzen H. Impact of bodyweight/body mass index on the effectiveness of emergency contraception with levonorgestrel: a pooled-analysis of three randomized controlled trials. Current Medical Research and Opinion 2015;31(12):2241-8.
44. Graesslin O, Korver T. The contraceptive efficacy of Implanon®: a review of clinical trials and marketing experience. European Journal of Contraception and Reproductive Health Care 2008;13(Suppl 1):4-12.
45. Glasier A, Cameron ST, Blithe D, Scherrer B, Mathe H, Levy D, et al. Can we identify women at risk of pregnancy despite using emergency contraception? Data from randomized trials of ulipristal acetate and levonorgestrel. Contraception. 2011/09/17 2011; Vol. 84, issue 4:363-7.
46. Kapp N, Abitbol JL, Mathe H, Scherrer B, Guillard H, Gainer E, et al. Effect of body weight and BMI on the efficacy of levonorgestrel emergency contraception. Contraception 2015;91(2):97-104.
47. McNicholas C, Zhao Q, Secura G, Allsworth JE, Madden T, Peipert JF. Contraceptive failures in overweight and obese combined hormonal contraceptive users. Obstetrics and Gynecology 2013;121(3):585-92.
48. Moreau C, Trussell J. Results from pooled Phase III studies of ulipristal acetate for emergency contraception. Contraception. 2012/07/10 2012.
49. Mornar S, Chan L-N, Mistretta S, Neustadt A, Martins S, Gilliam M. Pharmacokinetics of the etonogestrel contraceptive implant in obese women. American Journal of Obstetrics and Gynecology August 2012; Vol. 207, issue 110:e1-6. [NCT00724438]
50. Neustadt A, Gilliam M. Pharmacokinetics of Implanon in obese women. http://clinicaltrials.gov/ct2/show/NCT00724438 (accessed 15 Sep 2009). [NCT00724438]
51. ®-2 contraceptives. Studies in Family Planning 1988;19(2):81-94.
52. Sivin I, Mishell DR, Diaz S, Biswas A, Alvarez F, Darney P, et al. Prolonged effectiveness of Norplant(R) capsule implants: a 7-year study. Contraception 2000, issue 3:187-94.
53. Weisberg E, Fraser IS, Lacarra M, Mishell DR, Jr, Alvarez F, et al. Efficacy, bleeding patterns, and side effects of a 1-year contraceptive vaginal ring. Contraception 1999;59(5):311-8.
54. American Society for Emergency Contraception. Efficacy of emergency contraception and body weight: Current understanding and recommendations. http://americansocietyforec.org/uploads/3/2/7/0/3270267/asec_ec_efficacy_and_weight_statement.pdf. [Princeton, New Jersey], American Society for Emergency Contraception [ASEC], 2015 Jan., January 2015 (accessed 12 April 2016).
55. Brunner Huber LR, Hogue CJ, Stein AD, Drews C, Zieman M. Body mass index and risk for oral contraceptive failure: a case-cohort study in South Carolina. Annals of Epidemiology 2006;16(8):637-43.
56. Brunner LR, Hogue CJ. The role of body weight in oral contraceptive failure: results from the 1995 National Survey of Family Growth. Annals of Epidemiology 2005;15(7):492-9.
57. Brunner Huber LR, Toth JL. Obesity and oral contraceptive failure: findings from the 2002 National Survey of Family Growth. American Journal of Epidemiology 2007;166(11):1306-11.
58. Callegari LS, Nelson KM, Arterburn DE, Prager SW, Schiff MA, Schwarz EB. Factors associated with lack of effective contraception among obese women in the United States. Contraception 2014;90(3):265-71.
59. Centers for Disease Control and Prevention. Defining Adult Overweight and Obesity. www.cdc.gov/obesity/adult/defining.html (accessed 12 May 2016).
60. Creinin MD, Baker JB, Eisenberg L, Ginde S, Turok DK, Westhoff CL. Levonorgestrel levels in nonobese and obese women using LNG20, a new intrauterine contraceptive. Obstetrics and Gynecology 2015;125 Suppl 1:84S-5S.
61. Dinger JC, Cronin M, Mohner S, Schellschmidt I, Minh TD, Westhoff C. Oral contraceptive effectiveness according to body mass index, weight, age, and other factors. American Journal of Obstetrics and Gynecology 2009;201(3):263.e1-9.
62. Dinger J, Minh TD, Buttmann N, Bardenheuer K. Effectiveness of oral contraceptive pills in a large U.S. cohort comparing progestogen and regimen. Obstetrics and Gynecology. 2011/01/11 2011; Vol. 117, issue 1:33-40.
63. European Consortium for Emergency Contraception. Efficacy of emergency contraception and body weight. Current understanding and recommendations. www.ec-ec.org/custom-content/uploads/2015/12/ECEC-EC-Body-Weight-November-2015.pdf November 2015 (accessed 12 Aprl 2016).
64. Edelman AB, Carlson NE, Cherala G, Munar MY, Stouffer RL, Cameron JL, et al. Impact of obesity on oral contraceptive pharmacokinetics and hypothalamic-pituitary-ovarian activity. Contraception 2009;80(2):119-27.
65. Edelman AB, Cherala G, Munar MY, McInnis M, Stanczyk FZ, Jensen JT. Correcting oral contraceptive pharmacokinetic alterations due to obesity: a randomized controlled trial. Contraception 2014;90(5):550-6.
66. Gallo MF, Lopez LM, Grimes DA, Carayon F, Schulz KF, Helmerhorst FM. Combination contraceptives: effects on weight. Cochrane Database of Systematic Reviews 2014, Issue 1. [DOI: 10.1002/14651858.CD003987.pub5]
67. Schünemann H, Brozek J, Guyatt G, Oxman A. GRADE Handbook [updated October 2013]. http://gdt.guidelinedevelopment.org/central_prod/_design/client/handbook/handbook.html (accessed 29 December 2015).
68. Grimes DA, Shields WC. Family planning for obese women: challenges and opportunities. Contraception 2005;72(1):1-4.
69. Grimes DA, Schulz KF, Raymond EG. Surrogate end points in women's health research: science, protoscience, and pseudoscience. Fertility and Sterility 2010;93(6):1731-4.
70. Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from www.cochrane-handbook.org. John Wiley & Sons, Ltd, (accessed 26 Mar 2012).
71. Holt VL, Cushing-Haugen KL, Daling JR. Body weight and risk of oral contraceptive failure. Obstetrics and Gynecology 2002;99(5 Pt 1):820-7.
72. Holt VL, Scholes D, Wicklund KG, Cushing-Haugen KL, Daling JR. Body mass index, weight, and oral contraceptive failure risk. Obstetrics and Gynecology 2005;105(1):46-52.
73. Jatlaoui TC, Curtis KM. Safety and effectiveness data for emergency contraceptive pills among women with obesity: a systematic review. Contraception 2016 May 24 [Epub ahead of print].
74. Kavanaugh ML, Jerman J, Finer LB. Changes in use of long-acting reversible contraceptive methods among U.S. women, 2009-2012. Obstetrics and Gynecology 2015;126(5):917-27.
75. Kohn JE, Lopez PM, Simons HR. Weight and body mass index among female contraceptive clients. Contraception 2015;91(6):470-3.
76. Lopez LM, Edelman A, Chen M, Otterness C, Trussell J, HelmerhorstM Progestin-only contraceptives: effects on weight. Cochrane Database of Systematic Reviews 2013, Issue 7. [DOI: 10.1002/14651858.CD008815.pub3]
77. Lopez LM, Grimes DA, Schulz KF. Steroidal contraceptives: effect on carbohydrate metabolism in women without diabetes mellitus. Cochrane Database of Systematic Reviews 2014, Issue 4. [DOI: 10.1002/14651858.CD006133.pub5]
78. McKeating A, O'Higgins A, Turner C, McMahon L, Sheehan SR, Turner MJ. The relationship between unplanned pregnancy and maternal body mass index 2009-2012. European Journal of Contraception and Reproductive Health Care 2015;20(6):409-18.
79. Merki-Feld GS, Skouby S, Serfaty D, Lech M, Bitzer J, Crosignani PG, et al. European society of contraception statement on contraception in obese women. European Journal of Contraception and Reproductive Health Care 2015;20(1):19-28.
80. Morrell KM, Cremers S, Westhoff CL, Davis AR. Relationship between etonogestrel level and BMI in women using the contraceptive implant for more than 1 year. Contraception 2016;93(3):263-5. [PUBMED: 26577754]
81. Ng M, Robinson M, Thomson B, Graetz N, Margano C, Mullany EC. Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet 2014;384(9945):766-81.
82. Ogden CL, Carroll MD, Kit BK, Flegal KM. Prevalence of childhood and adult obesity in the united states, 2011-2012. JAMA 2014;311(8):806-14.
83. Segall-Gutierrez P, Taylor D, Liu X, Stanczyk F, Azen S, Mishell DR. Follicular development and ovulation in extremely obese women receiving depo-medroxyprogesterone acetate subcutaneously. Contraception 2010;81(6):487-95.
84. Sivin I, Wan L, Ranta S, Alvarez F, Brache V, Mishell DR, et al. Levonorgestrel concentrations during 7 years of continuous use of Jadelle contraceptive implants. Contraception 2001;64(1):43-9.
85. Strauss SE, Richardson WS, Glasziou P, Haynes RB. Evidence-based Medicine: How to Practice and Teach EBM. Third Edition. New York: Churchill Livingstone, 2005.
86. Trussell J, Schwarz EB, Guthrie K. Obesity and oral contraceptive pill failure. Contraception 2009;79(5):334-8.
87. United Nations, Department of Economic and Social Affairs. World Contraceptive Patterns 2015. www.un.org/en/development/desa/population/publications/ (accessed 23 February 2015).
88. Vessey M. Oral contraceptive failures and body weight: findings in a large cohort study. Journal of Family Planning and Reproductive Health Care 2001;27(2):90-1.
89. GA Wells, Shea B, O'Connell D, Peterson J, Welch V, Losos M, Tugwell P. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses. www.ohri.ca/programs/clinical_epidemiology/oxford.asp (accessed 6 October 2015).
90. Westhoff C. Higher body weight does not affect NuvaRing's efficacy (abstract). Obstetrics and Gynecology 2005;105(4 Suppl):56S.
91. Westhoff C. Subject weight and oral contraceptive efficacy in recent clinical trials (abstract). Contraception 2008;78(2):167.
92. Westhoff C, Torgal A, Mayeda ER, Lerner J, Paik M. Ovarian suppression during oral contraceptive use in normal-weight and obese women. Contraception 2009;80(2):210.
93. Westhoff CL, Torgal AH, Mayeda ER, Petrie K, Thomas T, Dragoman M, et al. Pharmacokinetics and ovarian suppression during use of a contraceptive vaginal ring in normal-weight and obese women. American Journal of Obstetrics and Gynecology 2012;207(1):39.e1-6.
94. Westhoff CL, Torgal AT, Mayeda ER, Shimoni N, Stanczyk FZ, Pike MC. Predictors of noncompliance in an oral contraceptive clinical trial. Contraception 2012;85(5):465-9.
95. Westhoff CL, Reinecke I, Bangerter K, Merz M. Impact of body mass index on suppression of follicular development and ovulation using a transdermal patch containing 0.55-mg ethinyl estradiol/2.1-mg gestodene: a multicenter, open-label, uncontrolled study over three treatment cycles. Contraception 2014;90(3):272-9.
96. World Health Organization. Obesity. http://www.euro.who.int/en/what-we-do/health-topics/noncommunicable-diseases/obesity (accessed 27 Dec 2012).