{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,24]],"date-time":"2026-10-24T02:31:09Z","timestamp":1792809069253,"version":"4.5.0"},"reference-count":82,"publisher":"Elsevier BV","license":[{"start":{"date-parts":[[2023,3,1]],"date-time":"2023-03-01T00:00:00Z","timestamp":1677628800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/tdm\/userlicense\/1.0\/"},{"start":{"date-parts":[[2023,3,1]],"date-time":"2023-03-01T00:00:00Z","timestamp":1677628800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.elsevier.com\/legal\/tdmrep-license"},{"start":{"date-parts":[[2022,12,20]],"date-time":"2022-12-20T00:00:00Z","timestamp":1671494400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100014848","name":"Arnold Ventures","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100014848","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000008","name":"David and Lucile Packard Foundation","doi-asserted-by":"publisher","award":["2015-63012"],"award-info":[{"award-number":["2015-63012"]}],"id":[{"id":"10.13039\/100000008","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["clinicalkey.com","clinicalkey.com.au","clinicalkey.es","clinicalkey.fr","clinicalkey.jp","contraceptionjournal.org","elsevier.com","sciencedirect.com"],"crossmark-restriction":true},"short-container-title":["Contraception"],"published-print":{"date-parts":[[2023,3]]},"DOI":"10.1016\/j.contraception.2022.109925","type":"journal-article","created":{"date-parts":[[2022,12,16]],"date-time":"2022-12-16T20:09:07Z","timestamp":1671221347000},"page":"109925","update-policy":"https:\/\/doi.org\/10.1016\/elsevier_cm_policy","source":"Crossref","is-referenced-by-count":26,"special_numbering":"C","title":["Effectiveness and efficacy rates of progestin-only pills: A comprehensive literature review"],"prefix":"10.1016","volume":"119","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6016-1568","authenticated-orcid":false,"given":"Carmela","family":"Zuniga","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kelly","family":"Blanchard","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cynthia C.","family":"Harper","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandra","family":"Wollum","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katherine","family":"Key","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jillian T.","family":"Henderson","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"78","reference":[{"key":"10.1016\/j.contraception.2022.109925_bib0001","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1089\/jwh.2015.5312","article-title":"Prescription birth control access among U.S. women at risk of unintended pregnancy","volume":"25","author":"Grindlay","year":"2016","journal-title":"J Womens Health (Larchmt)"},{"key":"10.1016\/j.contraception.2022.109925_bib0002","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1363\/4408412","article-title":"Barriers to contraception and interest in over-the-counter access among low-income women: a qualitative study","volume":"44","author":"Dennis","year":"2012","journal-title":"Perspect Sex Reprod Health"},{"key":"10.1016\/j.contraception.2022.109925_bib0003","unstructured":"HRA Pharma. Perrigo's HRA Pharma submits application to FDA for first-ever OTC birth control pill. n.d. https:\/\/www.hra-pharma.com\/articles\/perrigos-hra-pharma-submits-application-to-fda-for-first-ever-otc-birth-control-pill-66 (accessed October 7, 2022)."},{"key":"10.1016\/j.contraception.2022.109925_bib0004","unstructured":"OCs OTC Working Group. Statement of purpose. n.d. https:\/\/ocsotc.org\/statement-of-purpose\/ (accessed March 1, 2022)."},{"key":"10.1016\/j.contraception.2022.109925_bib0005","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.whi.2017.11.006","article-title":"Interest in over-the-counter access to a progestin-only pill among women in the United States","volume":"28","author":"Grindlay","year":"2018","journal-title":"Women's Heal Issues"},{"key":"10.1016\/j.contraception.2022.109925_bib0006","doi-asserted-by":"crossref","first-page":"666","DOI":"10.1016\/j.contraception.2012.05.018","article-title":"User characteristics and out-of-pocket expenditures for progestin-only versus combined oral contraceptives","volume":"86","author":"Liang","year":"2012","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0007","doi-asserted-by":"crossref","first-page":"1626","DOI":"10.1089\/jwh.2020.8706","article-title":"A randomized study evaluating the effect of evidence-based information on clinician attitudes about moving oral contraceptives over the counter","volume":"30","author":"Wollum","year":"2021","journal-title":"J Womens Health (Larchmt)"},{"key":"10.1016\/j.contraception.2022.109925_bib0008","doi-asserted-by":"crossref","DOI":"10.1002\/14651858.CD007541.pub3","article-title":"Progestin-only pills for contraception","author":"Grimes","year":"2013","journal-title":"Cochrane Database Syst Rev"},{"key":"10.1016\/j.contraception.2022.109925_bib0009","series-title":"Contracept Technol","first-page":"95","article-title":"Efficacy, safety, and personal considerations","author":"Trussell","year":"2018"},{"issue":"9","key":"10.1016\/j.contraception.2022.109925_bib0010","doi-asserted-by":"crossref","first-page":"2422","DOI":"10.1093\/humrep\/dem184","article-title":"Contraceptive failure rates in France: results from a population-based survey","volume":"22","author":"Moreau","year":"2007","journal-title":"Hum Reprod"},{"key":"10.1016\/j.contraception.2022.109925_bib0011","series-title":"Contraceptive Efficacy","first-page":"829","author":"Trussel","year":"2018"},{"key":"10.1016\/j.contraception.2022.109925_bib0012","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1111\/j.1745-7599.2009.00473.x","article-title":"Considerations for the use of progestin-only contraceptives","volume":"22","author":"Freeman","year":"2010","journal-title":"J Am Acad Nurse Pract"},{"key":"10.1016\/j.contraception.2022.109925_bib0013","doi-asserted-by":"crossref","first-page":"310","DOI":"10.1016\/j.contraception.2017.07.168","article-title":"Cervical mucus and contraception: what we know and what we don't","volume":"96","author":"Han","year":"2017","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0014","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.contraception.2004.07.016","article-title":"Maintenance of ovulation inhibition with the 75-microg desogestrel-only contraceptive pill (Cerazette) after scheduled 12-h delays in tablet intake","volume":"71","author":"Korver","year":"2005","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0015","doi-asserted-by":"crossref","first-page":"303","DOI":"10.1016\/j.contraception.2015.12.007","article-title":"Maintenance of ovulation inhibition with a new progestogen-only pill containing drospirenone after scheduled 24-h delays in pill intake","volume":"93","author":"Duijkers","year":"2016","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0016","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.contraception.2022.09.002","article-title":"The effect of deliberate non-adherence to a norgestrel progestin-only pill: a randomized, crossover study","volume":"117","author":"Glasier","year":"2023","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0017","first-page":"153","article-title":"Clinical pearls: factors affecting reported contraceptive efficacy rates in clinical studies","volume":"47","author":"Burkman","year":"2002","journal-title":"Int J Fertil Womens Med"},{"key":"10.1016\/j.contraception.2022.109925_bib0018","doi-asserted-by":"crossref","first-page":"199","DOI":"10.1016\/j.bpobgyn.2008.11.008","article-title":"Understanding contraceptive failure","volume":"23","author":"Trussell","year":"2009","journal-title":"Best Pract Res Clin Obstet Gynaecol"},{"key":"10.1016\/j.contraception.2022.109925_bib0019","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.contraception.2021.08.016","article-title":"A review of the effectiveness of a progestogen-only pill containing norgestrel 75 \u00b5g\/day","volume":"105","author":"Glasier","year":"2022","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0020","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1016\/0010-7824(82)90104-4","article-title":"The progestogen-only mini-pill","volume":"26","author":"Graham","year":"1982","journal-title":"Contraception"},{"issue":"12","key":"10.1016\/j.contraception.2022.109925_bib0021","doi-asserted-by":"crossref","first-page":"1549","DOI":"10.1111\/aogs.13688","article-title":"Multicenter, phase III trials on the contraceptive efficacy, tolerability and safety of a new drospirenone-only pill","volume":"98","author":"Palacios","year":"2019","journal-title":"Acta Obstet Gynecol Scand"},{"key":"10.1016\/j.contraception.2022.109925_bib0022","unstructured":"R Core Team (2022). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL https:\/\/www.R-project.org\/."},{"key":"10.1016\/j.contraception.2022.109925_bib0023","article-title":"RoB 2: a revised tool for assessing risk of bias in randomised trials","volume":"366","author":"Sterne","year":"2019","journal-title":"BMJ"},{"key":"10.1016\/j.contraception.2022.109925_bib0024","article-title":"ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions","volume":"355","author":"Sterne","year":"2016","journal-title":"BMJ"},{"key":"10.1016\/j.contraception.2022.109925_bib0025","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1002\/sim.4780100206","article-title":"Methodological pitfalls in the analysis of contraceptive failure","volume":"10","author":"Trussell","year":"1991","journal-title":"Stat Med"},{"key":"10.1016\/j.contraception.2022.109925_bib0026","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1016\/S0015-0282(16)39552-8","article-title":"Clinical experience with microdose d-Norgestrel as an oral contraceptive","volume":"24","author":"Apelo","year":"1973","journal-title":"Fertil Steril"},{"key":"10.1016\/j.contraception.2022.109925_bib0027","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1016\/0010-7824(89)90035-8","article-title":"Mini-pill in lactating women","volume":"39","author":"Canto","year":"1989","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0028","doi-asserted-by":"crossref","first-page":"185","DOI":"10.5694\/j.1326-5377.1969.tb105693.x","article-title":"Chlormadinone acetate 0-5 mg. A report on its effectiveness in continuous use as an oral contraceptive","volume":"2","author":"Christie","year":"1969","journal-title":"Med J Aust"},{"key":"10.1016\/j.contraception.2022.109925_bib0029","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1136\/bmj.3.5668.471-c","article-title":"Progestogen-only oral contraceptives","volume":"3","author":"Cox","year":"1969","journal-title":"Br Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0030","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1016\/0010-7824(93)90106-H","article-title":"A multicenter clinical trial of a progestin-only oral contraceptive in lactating women","volume":"47","author":"Dunson","year":"1993","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0031","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1136\/bmj.3.5820.195","article-title":"Clinical and laboratory findings in a trial of norgestrel, a low-does progestogen-only contraceptive","volume":"3","author":"Eckstein","year":"1972","journal-title":"Br Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0032","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1017\/S0021932000010154","article-title":"Long-term use of daily administration of low doses of norgestrel as an oral contraceptive","volume":"7","author":"Foss","year":"1975","journal-title":"J Biosoc Sci"},{"key":"10.1016\/j.contraception.2022.109925_bib0033","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1136\/bmj.4.5629.489","article-title":"Contraceptive action of continuous low doses of norgestrel","volume":"4","author":"Foss","year":"1968","journal-title":"Br Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0034","doi-asserted-by":"crossref","first-page":"708","DOI":"10.1111\/j.1471-0528.1977.tb12686.x","article-title":"A comparative study of three low dose progestogens, chlormadinone acetate, megestrol acetate and norethisterone, as oral contraceptives","volume":"84","author":"Hawkins","year":"1977","journal-title":"Br J Obstet Gynaecol"},{"key":"10.1016\/j.contraception.2022.109925_bib0035","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/0010-7824(71)90040-0","article-title":"Hormonal contraception with 0.5 mg chlormadinone acetate by continuous administration","volume":"3","author":"Heinen","year":"1971","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0036","first-page":"125","article-title":"Preliminary evaluation of fertility control with continuous microdose norgestrel","volume":"5","author":"Hernandez-Torres","year":"1970","journal-title":"Adv Plan Parent"},{"key":"10.1016\/j.contraception.2022.109925_bib0037","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1016\/j.contraception.2015.07.014","article-title":"Drospirenone-only oral contraceptive: results from a multicenter noncomparative trial of efficacy, safety and tolerability","volume":"92","author":"Archer","year":"2015","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0038","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1016\/S0140-6736(69)92599-9","article-title":"Low-dose continuous chlormadinone acetate as an oral contraceptive","volume":"294","author":"Howard","year":"1969","journal-title":"Lancet"},{"key":"10.1016\/j.contraception.2022.109925_bib0039","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/S0015-0282(16)37446-5","article-title":"Experience with chlormadinone acetate in continuous low dose as an oral contraceptive","volume":"21","author":"Jeppsson","year":"1970","journal-title":"Fertil Steril"},{"key":"10.1016\/j.contraception.2022.109925_bib0040","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/0010-7824(74)90012-2","article-title":"Continuous microdose (0.3 mg) quingestanol acetate as an oral contraceptive agent","volume":"9","author":"Jubhari","year":"1974","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0041","first-page":"17","article-title":"Fertility control by continuous administration of d-Norgestrel, 0.03 mg","volume":"17","author":"Kesser\u00fc","year":"1972","journal-title":"Int J Fertil"},{"key":"10.1016\/j.contraception.2022.109925_bib0042","first-page":"71","article-title":"Five years of fertility control with microdose norgestrel: an updated clinical review","volume":"13","author":"Korba","year":"1974","journal-title":"J Reprod Med"},{"key":"10.1016\/j.contraception.2022.109925_bib0043","first-page":"169","article-title":"A double-blind study comparing the contraceptive efficacy, acceptability and safety of two progestogen-only pills containing desogestrel 75 \u03bcg\/day or levonorgestrel 30 \u03bcg\/day: Collaborative Study Group on the Desogestrel-containing Progestogen-only Pill","volume":"3","author":"Korver","year":"1998","journal-title":"Eur J Contracept Reprod Heal Care"},{"key":"10.1016\/j.contraception.2022.109925_bib0044","doi-asserted-by":"crossref","first-page":"2428","DOI":"10.1093\/humrep\/dem177","article-title":"A novel estrogen-free oral contraceptive pill for women: multicentre, double-blind, randomized controlled trial of mifepristone and progestogen-only pill (levonorgestrel)","volume":"22","author":"Lakha","year":"2007","journal-title":"Hum Reprod"},{"key":"10.1016\/j.contraception.2022.109925_bib0045","first-page":"165","article-title":"Fertility control with continuous microdose norgestrel","volume":"8","author":"Laurie","year":"1972","journal-title":"J Reprod Med"},{"key":"10.1016\/j.contraception.2022.109925_bib0046","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1185\/03007997209111145","article-title":"Experience with norethisterone 0.35\u2009mg. as an oral contraceptive - a preliminary report","volume":"1","author":"Lawson","year":"1972","journal-title":"Curr Med Res Opin"},{"key":"10.1016\/j.contraception.2022.109925_bib0047","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1016\/0010-7824(72)90053-4","article-title":"The evaluation of quingestanol acetate as a low dose oral contraceptive","volume":"6","author":"Maqueo","year":"1972","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0048","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/0010-7824(71)90014-X","article-title":"Contraceptive efficacy of single and divided doses of chlormadinone acetate","volume":"4","author":"Aznar-Ramos","year":"1971","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0049","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/S0015-0282(16)36185-4","article-title":"Continuous progestogen contraception: a dose relationship study with chlormadinone acetate","volume":"18","author":"Martinez-Manautou","year":"1967","journal-title":"Fertil Steril"},{"key":"10.1016\/j.contraception.2022.109925_bib0050","doi-asserted-by":"crossref","first-page":"730","DOI":"10.1136\/bmj.2.5554.730","article-title":"Daily progestogen for contraception: a clinical study","volume":"2","author":"Martinez-Manautou","year":"1967","journal-title":"Br Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0051","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/S0015-0282(16)35825-3","article-title":"Low doses of progestogen as an approach to fertility control","volume":"17","author":"Martinez-Manautou","year":"1966","journal-title":"Fertil Steril"},{"key":"10.1016\/j.contraception.2022.109925_bib0052","series-title":"Adv. Plan. Parenthood. Proc. 9th Annu. Meet. Am. Assocation Plan. Parent. Physicians, Kansas City, MO","first-page":"124","article-title":"The clinical evaluation of norethindrone in cyclic and continous regimens","author":"McQuarrie","year":"1972"},{"key":"10.1016\/j.contraception.2022.109925_bib0053","doi-asserted-by":"crossref","first-page":"730","DOI":"10.1136\/bmj.2.5659.730","article-title":"Preliminary evaluation of four oral contraceptives containing only progestogens","volume":"2","author":"Mears","year":"1969","journal-title":"Br Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0054","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1016\/0010-7824(91)90104-N","article-title":"A comparative study of a progestin-only oral contraceptive versus non-hormonal methods in lactating women in Buenos Aires, Argentina","volume":"44","author":"Moggia","year":"1991","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0055","first-page":"169","article-title":"Evaluation of the contraceptive efficacy of quingestanol acetate (W 4540) when administered as an oral low-dose conraceptive in the puerperium","volume":"8","author":"Moggia","year":"1972","journal-title":"J Reprod Med"},{"key":"10.1016\/j.contraception.2022.109925_bib0056","first-page":"186","article-title":"Evaluation of the contraceptive efficacy of Quingestanol acetate in daily microdose and post coitum","volume":"10","author":"Moggia","year":"1973","journal-title":"J Reprod Med"},{"key":"10.1016\/j.contraception.2022.109925_bib0057","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1016\/0010-7824(74)90061-4","article-title":"A randomized contraceptive trial comparing a daily progestogen with a combined oral contraceptive steroid","volume":"9","author":"Paulsen","year":"1974","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0058","first-page":"272","article-title":"Pregnancy rate of a progestogen oral contraceptive","volume":"222","author":"Postlethwaite","year":"1979","journal-title":"Practitioner"},{"key":"10.1016\/j.contraception.2022.109925_bib0059","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1016\/0010-7824(72)90029-7","article-title":"Daily chlormadinone acetate as an oral contraceptive","volume":"5","author":"Bernstein","year":"1972","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0060","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1016\/0010-7824(72)90067-4","article-title":"Clinical study of a continuous daily micro-dose progestogen contraceptive\u2013d-norgestrel","volume":"5","author":"Rice-Wray","year":"1972","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0061","unstructured":"Scharff H. Clinical experience with d-norgestrel as a continuous microdose. Presented at the Seventh World Congress on Fertility and Sterility, Tokyo, October 1971."},{"key":"10.1016\/j.contraception.2022.109925_bib0062","doi-asserted-by":"crossref","first-page":"243","DOI":"10.1016\/0010-7824(82)90047-6","article-title":"A randomized, double-blind study of two combined and two progestogen-only oral contraceptives","volume":"25","author":"Sheth","year":"1982","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0063","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1016\/S0010-7824(87)80003-3","article-title":"Clinical experience with ethynodiol diacetate 0.5 mg daily as an oral contraceptive","volume":"35","author":"Shroff","year":"1987","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0064","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1016\/0010-7824(74)90038-9","article-title":"Experience with 50 mcg and 75 mcg dl-norgestrel as a mini-pill in India","volume":"10","author":"Tejuja","year":"1974","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0065","first-page":"460","article-title":"Studies of \u201cmini-micro\u201d contraceptive doses of a new progestrogen","volume":"13","author":"Tyler","year":"1968","journal-title":"Int J Fertil"},{"key":"10.1016\/j.contraception.2022.109925_bib0066","doi-asserted-by":"crossref","first-page":"915","DOI":"10.1016\/S0140-6736(72)91492-4","article-title":"Randomised double-blind trial of four oral progestagen-only contraceptives","volume":"299","author":"Vessey","year":"1972","journal-title":"Lancet"},{"key":"10.1016\/j.contraception.2022.109925_bib0067","first-page":"117","article-title":"Progestogen-only oral contraception. Findings in a large prospective study with special reference to effectiveness","volume":"10","author":"Vessey","year":"1985","journal-title":"Br J Fam Plann"},{"key":"10.1016\/j.contraception.2022.109925_bib0068","first-page":"295","article-title":"Low dosage progestagen as an oral contraceptive: a clinical study","volume":"109","author":"Whyte","year":"1973","journal-title":"Can Med Assoc J"},{"key":"10.1016\/j.contraception.2022.109925_bib0069","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1136\/bmj.2.5600.263","article-title":"Antifertility effect of continuous low-dosage oral progestogen therapy","volume":"2","author":"Za\u00f1artu","year":"1968","journal-title":"Br Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0070","first-page":"84","article-title":"The efficacy of the progestogen-only pill as a contraceptive method","volume":"16","author":"Bisset","year":"1990","journal-title":"Br J Fam Plann"},{"key":"10.1016\/j.contraception.2022.109925_bib0071","first-page":"87","article-title":"Low-dosage oral progestogens to control fertility. I. Clinical investigation","volume":"43","author":"Zanartu","year":"1974","journal-title":"Obstet Gynecol"},{"key":"10.1016\/j.contraception.2022.109925_bib0072","first-page":"121","article-title":"Daily microdose norgestrel as a contraceptive: a preliminary report","volume":"7","author":"Statzer","year":"1972","journal-title":"Adv Plan Parent"},{"key":"10.1016\/j.contraception.2022.109925_bib0073","first-page":"55","article-title":"A study of a progestogen only oral contraceptive for lactating women in Khartoum, Sudan","volume":"29","author":"Cerais","year":"1991","journal-title":"Sudan Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0074","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.contraception.2009.02.013","article-title":"The risk of unintended pregnancies in users of the contraceptive patch compared to users of oral contraceptives in the UK General Practice Research Database","volume":"80","author":"Jick","year":"2009","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0075","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1016\/0002-9378(71)90624-7","article-title":"Continuous norethindrone, 0.35 mg, as an oral contraceptive agent","volume":"109","author":"Board","year":"1971","journal-title":"Am J Obstet Gynecol"},{"key":"10.1016\/j.contraception.2022.109925_bib0076","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1097\/00007611-197601000-00017","article-title":"Contraception with norethindrone 0.35 mg administered continuously","volume":"69","author":"Board","year":"1976","journal-title":"South Med J"},{"key":"10.1016\/j.contraception.2022.109925_bib0077","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1016\/0010-7824(90)90077-9","article-title":"Clinical experience with the progestogen-only pill","volume":"42","author":"Broome","year":"1990","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0078","doi-asserted-by":"crossref","first-page":"1116","DOI":"10.1016\/S0140-6736(69)91641-9","article-title":"Chlormadinone acetate as oral contraceptive","volume":"293","author":"Butler","year":"1969","journal-title":"Lancet"},{"key":"10.1016\/j.contraception.2022.109925_bib0079","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1016\/0010-7824(90)90077-9","article-title":"Clinical experience with the progestogen-only pill","volume":"42","author":"Broom","year":"1990","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0080","doi-asserted-by":"crossref","first-page":"604","DOI":"10.1016\/j.contraception.2013.04.001","article-title":"The creeping pearl: why has the rate of contraceptive failure increased in clinical trials of combined hormonal contraceptive pills?","volume":"88","author":"Trussell","year":"2013","journal-title":"Contraception"},{"key":"10.1016\/j.contraception.2022.109925_bib0081","doi-asserted-by":"crossref","first-page":"1017","DOI":"10.1016\/0002-9378(93)90331-C","article-title":"Contraceptive efficacy of a monophasic oral contraceptive containing desogestrel","volume":"168","author":"Corson","year":"1993","journal-title":"Am J Obstet Gynecol"},{"key":"10.1016\/j.contraception.2022.109925_bib0082","first-page":"87","article-title":"Recommendation for confidence interval and sample size calculation for the Pearl Index","volume":"8","author":"Gerlinger","year":"2003","journal-title":"Eur J Contracept Reprod Heal Care"}],"container-title":["Contraception"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0010782422004486?httpAccept=text\/xml","content-type":"text\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.elsevier.com\/content\/article\/PII:S0010782422004486?httpAccept=text\/plain","content-type":"text\/plain","content-version":"vor","intended-application":"text-mining"}],"deposited":{"date-parts":[[2025,9,14]],"date-time":"2025-09-14T20:22:00Z","timestamp":1757881320000},"score":1,"resource":{"primary":{"URL":"https:\/\/linkinghub.elsevier.com\/retrieve\/pii\/S0010782422004486"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,3]]},"references-count":82,"alternative-id":["S0010782422004486"],"URL":"https:\/\/doi.org\/10.1016\/j.contraception.2022.109925","relation":{},"ISSN":["0010-7824"],"issn-type":[{"value":"0010-7824","type":"print"}],"subject":[],"published":{"date-parts":[[2023,3]]},"assertion":[{"value":"Elsevier","name":"publisher","label":"This article is maintained by"},{"value":"Effectiveness and efficacy rates of progestin-only pills: A comprehensive literature review","name":"articletitle","label":"Article Title"},{"value":"Contraception","name":"journaltitle","label":"Journal Title"},{"value":"https:\/\/doi.org\/10.1016\/j.contraception.2022.109925","name":"articlelink","label":"CrossRef DOI link to publisher maintained version"},{"value":"article","name":"content_type","label":"Content Type"},{"value":"\u00a9 2022 The Authors. Published by Elsevier Inc.","name":"copyright","label":"Copyright"}],"article-number":"109925"}}