Combined Oral Contraceptive Adherence and Pregnancy Rates.

To assess the relationship of adherence and pregnancy in participants using an estetrol and drospirenone combined oral contraceptive. We performed a secondary analysis for which we pooled data from two parallel, multicenter, phase 3 trials (United States and Canada, Europe and Russia) that enrolled participants 16-50 years of age to receive estetrol 15 mg and drospirenone 3 mg in a 24 hormone and four placebo pills regimen for up to 13 cycles. Participants reported pill intake, sexual intercourse, and other contraceptive use on paper diaries. We limited this efficacy analysis to at-risk cycles (one or more reported acts of intercourse and no other contraceptive use) in participants 16-35 years of age at screening. We excluded cycles with other contraceptive use unless pregnancy occurred in that cycle. We assessed primarily the relationship between number of pills not taken per cycle and pregnancies and, secondarily, when pregnancies occurred during product use with a test for trend and χ 2 analyses as appropriate. Among 2,837 participants in this analysis, 31 on-treatment pregnancies occurred during 26,455 at-risk cycles. Pregnancies occurred in 0.09%, 0.25%, 0.83%, and 1.6% of cycles in which participants reported they took all hormone pills (n=25,613 cycles) or did not take one (n=405 cycles), two (n=121 cycles), and more than two (n=314 cycles) hormone-containing pills, respectively ( P <.001). No pregnancies occurred in 2,216 cycles when one or more pills were missed and missed-pill instructions were followed. All pregnancies related to not taking pills occurred in the first three cycles. Pregnancy rates ranged from 0% to 0.21% per cycle with no significant trend by cycle ( P =.45). Pregnancy occurs more frequently when combined oral contraceptive users report not taking all hormone-containing pills per 28-day cycle and exceeds 1% only when more than two pills are not taken. Pregnancies in participants who reported missed pills occurred only when missed-pill instructions were not followed. A 0.09% pregnancy risk per cycle among users of a 24 hormone and four placebo pills formulation who report taking all pills likely approximates a true method-failure rate. Estetra SRL, an affiliate company of Mithra Pharmaceuticals. ClinicalTrials.gov , NCT02817828 and NCT02817841.

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Copyright © 2023 by the American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.

Déclaration de conflit d'intérêts

Financial Disclosure Mitchell D. Creinin has received speaking honoraria from Gedeon Richter, Mayne and Organon. He has served on the Advisory Boards for Evofem, Fuji Pharma, Gedeon Richter, GlaxoSmithKline, Mayne, Merck & Co., OLIC, Organon, and Searchlight. He has been a Consultant for Estetra SRL (an affiliate company of Mithra Pharmaceuticals [includes support for medical and safety oversight of these studies]), Libbs, Mayne, and Medicines360, and his university department receives contraceptive research funding for Dr. Creinin from Chemo Research SL, Evofem, HRA Pharma, Medicines360, Merck & Co., and Sebela. Jeffrey T. Jensen has received payments for consulting from Bayer Healthcare, Evofem, Hope Medicine, Foundation Consumer Healthcare, Mayne Pharma, ViiV Healthcare, and TherapeuticsMD. OHSU has received research support from AbbVie, Bayer Healthcare, Daré, Estetra SPRL, Hope Medicine, Medicines360, Merck, Myovant, and Sebela. These companies and organizations may have a commercial or financial interest in the results of this research and technology. These potential conflicts of interest have been reviewed and managed by OHSU. Melissa J. Chen serves as an ad hoc speaker for Mayne Pharma and her university department received contraceptive research funding for Dr. Chen from Estetra SRL (an affiliate company of Mithra Pharmaceuticals). Amanda Black has received honoraria from Bayer, Organon, Pfizer, Searchlight and Mithra. She has received research funding from Linepharma and Bayer for the conduct of clinical trials. Dustin Costescu has received honoraria from Bayer, Organon, Merck, Duchesnay, and Searchlight Pharma. They serve on advisory boards for Bayer and Organon, and has previously served on an advisory board for Merck. Their department has received research funding from Bayer, Linepharma, and Mithra for the conduct of contraception and family planning studies. Jean-Michel Foidart is a member of the board at Mithra Pharmaceuticals, received honoraria from Gedeon Richter, and received financial support for the supervision of these studies.