{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T04:36:14Z","timestamp":1790742974092,"version":"4.1.0"},"reference-count":55,"publisher":"PeerJ","license":[{"start":{"date-parts":[[2025,6,12]],"date-time":"2025-06-12T00:00:00Z","timestamp":1749686400000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>The study aimed to examine the impact of combined oral contraceptive pill (OC) use on patellar tendon (PT) adaptation to resistance training in young women.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Fifteen users of OC (28\u00a0\u00b1\u00a03 years) (OC group) and 17 eumenorrheic non-users (32\u00a0\u00b1\u00a05 years) (NOC group) performed heavy resistance training of the knee extensors over a period equivalent to three menstrual or pill cycles. Maximal isometric strength of the knee extensor muscles, PT cross-sectional area (CSA), tensile stiffness, and shear wave velocity (SWV) were measured before and after the intervention using combined ultrasonography and dynamometry.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      The training period increased maximal isometric strength in both groups (\u224811%,\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0&lt;\u00a00.001) with no significant interaction with OC use (\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u00a00.965). Likewise, a small yet significant increase in proximal tendon CSA was observed (1.5\u00a0\u00b1\u00a01.6% for both groups, main training effect\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0&lt;\u00a00.001) without any significant interaction with OC use (\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u00a00.267). Tendon tensile stiffness also increased significantly (18.9\u00a0\u00b1\u00a026.3% in the OC group and 28.2\u00a0\u00b1\u00a035.1% in the NOC group, main effect:\n                      <jats:italic>P<\/jats:italic>\n                      \u00a0&lt;\u00a00.001) but was not significantly affected by OC use (interaction effect:\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u00a00.428). Tendon SWV measurements yielded similar results, indicating a main effect of training (+12% on average,\n                      <jats:italic>p<\/jats:italic>\n                      \u00a0=\u00a00.024) but no significant interaction with OC use.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>These findings suggest that OC use does not affect the increase in PT CSA and mechanical properties following short-term resistance training in young untrained females.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.7717\/peerj.19581","type":"journal-article","created":{"date-parts":[[2025,6,12]],"date-time":"2025-06-12T04:45:48Z","timestamp":1749703548000},"page":"e19581","source":"Crossref","is-referenced-by-count":5,"title":["Patellar tendon adaptations to resistance training in young women using combined oral contraceptives"],"prefix":"10.7717","volume":"13","author":[{"given":"Ingvild","family":"Vesterhus","sequence":"first","affiliation":[{"name":"Department for Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eirik R.","family":"Hesseberg","sequence":"additional","affiliation":[{"name":"Department for Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ken","family":"Fjeldberg","sequence":"additional","affiliation":[{"name":"Department for Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin K.","family":"Engstad","sequence":"additional","affiliation":[{"name":"Department for Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway"},{"name":"Department of Nutrution, University of Oslo, Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G\u00f8ran","family":"Paulsen","sequence":"additional","affiliation":[{"name":"Department for Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mette","family":"Hansen","sequence":"additional","affiliation":[{"name":"Department for Public Health, Aarhus University, Aarhus, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antoine","family":"Nordez","sequence":"additional","affiliation":[{"name":"Mouvement - Interactions - Performance, Universit\u00e9 de Nantes, Nantes, France"},{"name":"Institut Universitaire de France, Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lilian","family":"Lacourpaille","sequence":"additional","affiliation":[{"name":"Mouvement - Interactions - Performance, Universit\u00e9 de Nantes, Nantes, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olivier R.","family":"Seynnes","sequence":"additional","affiliation":[{"name":"Department for Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"4443","published-online":{"date-parts":[[2025,6,12]]},"reference":[{"key":"10.7717\/peerj.19581\/ref-1","doi-asserted-by":"publisher","first-page":"58","DOI":"10.1034\/j.1600-0838.2000.010002058.x","article-title":"Antagonist muscle coactivation during isokinetic knee extension","volume":"10","author":"Aagaard","year":"2000","journal-title":"Scandinavian Journal of Medicine & Science in Sports"},{"key":"10.7717\/peerj.19581\/ref-2","doi-asserted-by":"publisher","first-page":"495","DOI":"10.1002\/jor.1100090405","article-title":"Recombinant human insulin-like growth factor-I stimulates in vitro matrix synthesis and cell proliferation in rabbit flexor tendon","volume":"9","author":"Abrahamsson","year":"1991","journal-title":"Journal of Orthopaedic Research"},{"key":"10.7717\/peerj.19581\/ref-3","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1186\/s40798-015-0009-9","article-title":"Human tendon adaptation in response to mechanical loading: a systematic review and meta-analysis of exercise intervention studies on healthy adults","volume":"1","author":"Bohm","year":"2015","journal-title":"Sports Medicine\u2014Open"},{"key":"10.7717\/peerj.19581\/ref-4","doi-asserted-by":"publisher","first-page":"505","DOI":"10.1088\/0031-9155\/59\/3\/505","article-title":"In vivo evaluation of the elastic anisotropy of the human Achilles tendon using shear wave dispersion analysis","volume":"59","author":"Brum","year":"2014","journal-title":"Physics in Medicine and Biology"},{"key":"10.7717\/peerj.19581\/ref-5","doi-asserted-by":"publisher","first-page":"1035","DOI":"10.1152\/japplphysiol.01281.2007","article-title":"Effects of estrogen on the mechanical behavior of the human Achilles tendon in vivo","volume":"105","author":"Bryant","year":"2008","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-6","doi-asserted-by":"publisher","first-page":"557","DOI":"10.2165\/00007256-200737070-00001","article-title":"The influence of oral contraceptives on athletic performance in female athletes","volume":"37","author":"Burrows","year":"2007","journal-title":"Sports Medicine"},{"issue":"4","key":"10.7717\/peerj.19581\/ref-7","doi-asserted-by":"publisher","first-page":"582","DOI":"10.1249\/MSS.0000000000002824","article-title":"Low-load blood flow restriction and high-load resistance training induce comparable changes in patellar tendon properties","volume":"54","author":"Centner","year":"2021","journal-title":"Medicine & Science in Sports & Exercise"},{"key":"10.7717\/peerj.19581\/ref-8","doi-asserted-by":"publisher","first-page":"269","DOI":"10.1016\/j.maturitas.2003.11.009","article-title":"Are all estrogens the same?","volume":"47","author":"Coelingh\u00a0Bennink","year":"2004","journal-title":"Maturitas"},{"key":"10.7717\/peerj.19581\/ref-9","article-title":"Oral contraceptive pills","volume-title":"StatPearls","author":"Cooper","year":"2024"},{"key":"10.7717\/peerj.19581\/ref-10","doi-asserted-by":"publisher","first-page":"824","DOI":"10.3389\/fphys.2019.00824","article-title":"Influence of oral contraceptive use on adaptations to resistance training","volume":"10","author":"Dalgaard","year":"2019","journal-title":"Frontiers in Physiology"},{"key":"10.7717\/peerj.19581\/ref-11","doi-asserted-by":"publisher","first-page":"115","DOI":"10.1016\/j.cca.2017.05.002","article-title":"Reference intervals for plasma concentrations of adrenal steroids measured by LC-MS\/MS: impact of gender, age, oral contraceptives, body mass index and blood pressure status","volume":"470","author":"Eisenhofer","year":"2017","journal-title":"Clinica Chimica Acta"},{"key":"10.7717\/peerj.19581\/ref-12","doi-asserted-by":"publisher","first-page":"843","DOI":"10.1007\/s40279-021-01435-8","article-title":"Methodological considerations for studies in sport and exercise science with women as participants: a working guide for standards of practice for research on women","volume":"51","author":"Elliott-Sale","year":"2021","journal-title":"Sports Medicine"},{"key":"10.7717\/peerj.19581\/ref-13","doi-asserted-by":"publisher","first-page":"30","DOI":"10.1186\/s12877-019-1043-0","article-title":"Load magnitude affects patellar tendon mechanical properties but not collagen or collagen cross-linking after long-term strength training in older adults","volume":"19","author":"Eriksen","year":"2019","journal-title":"BMC Geriatrics"},{"key":"10.7717\/peerj.19581\/ref-14","doi-asserted-by":"publisher","first-page":"176","DOI":"10.1290\/0512089.1","article-title":"Quantitation of estrogen receptors and relaxin binding in human anterior cruciate ligament fibroblasts","volume":"42","author":"Faryniarz","year":"2006","journal-title":"In Vitro Cellular & Developmental Biology\u2014Animal"},{"key":"10.7717\/peerj.19581\/ref-15","doi-asserted-by":"publisher","first-page":"4","DOI":"10.1016\/j.contraception.2008.02.020","article-title":"Oral contraceptives and individual variability of circulating levels of ethinyl estradiol and progestins","volume":"78","author":"Goldzieher","year":"2008","journal-title":"Contraception"},{"key":"10.7717\/peerj.19581\/ref-16","doi-asserted-by":"publisher","first-page":"858610","DOI":"10.3389\/fbioe.2022.858610","article-title":"Patellar tendon shear wave velocity is higher and has different regional patterns in elite competitive alpine skiers than in healthy controls","volume":"10","author":"G\u00f6tschi","year":"2022","journal-title":"Frontiers in Bioengineering and Biotechnology"},{"key":"10.7717\/peerj.19581\/ref-17","doi-asserted-by":"publisher","first-page":"1207","DOI":"10.1007\/s40279-018-0872-x","article-title":"Effect of resistance training frequency on gains in muscular strength: a systematic review and meta-analysis","volume":"48","author":"Grgic","year":"2018","journal-title":"Sports Medicine"},{"key":"10.7717\/peerj.19581\/ref-18","doi-asserted-by":"publisher","first-page":"178","DOI":"10.1016\/j.jmbbm.2017.01.007","article-title":"Shear waves elastography for assessment of human Achilles tendon\u2019s biomechanical properties: an experimental study","volume":"69","author":"Haen","year":"2017","journal-title":"Journal of the Mechanical Behavior of Biomedical Materials"},{"key":"10.7717\/peerj.19581\/ref-19","doi-asserted-by":"publisher","first-page":"998","DOI":"10.1152\/japplphysiol.01255.2012","article-title":"Impact of oral contraceptive use and menstrual phases on patellar tendon morphology, biochemical composition, and biomechanical properties in female athletes","volume":"114","author":"Hansen","year":"2013","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-20","doi-asserted-by":"publisher","first-page":"139","DOI":"10.1007\/978-3-319-33943-6_13","article-title":"Sex hormones and tendon","volume":"920","author":"Hansen","year":"2016","journal-title":"Advances in Experimental Medicine and Biology"},{"key":"10.7717\/peerj.19581\/ref-21","doi-asserted-by":"publisher","first-page":"1385","DOI":"10.1152\/japplphysiol.90935.2008","article-title":"Effect of estrogen on tendon collagen synthesis, tendon structural characteristics, and biomechanical properties in postmenopausal women","volume":"106","author":"Hansen","year":"2009","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-22","doi-asserted-by":"publisher","first-page":"3005","DOI":"10.1113\/jphysiol.2007.147348","article-title":"Ethinyl oestradiol administration in women suppresses synthesis of collagen in tendon in response to exercise","volume":"586","author":"Hansen","year":"2008","journal-title":"Journal of Physiology"},{"key":"10.7717\/peerj.19581\/ref-23","doi-asserted-by":"publisher","first-page":"1435","DOI":"10.1152\/japplphysiol.90933.2008","article-title":"Effect of administration of oral contraceptives in vivo on collagen synthesis in tendon and muscle connective tissue in young women","volume":"106","author":"Hansen","year":"2009","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-24","doi-asserted-by":"publisher","first-page":"1715","DOI":"10.1007\/s00421-018-3903-2","article-title":"Shear-wave velocity of the patellar tendon and quadriceps muscle is increased immediately after maximal eccentric exercise","volume":"118","author":"Heales","year":"2018","journal-title":"European Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-25","doi-asserted-by":"publisher","first-page":"2485","DOI":"10.1088\/0031-9155\/61\/6\/2485","article-title":"In vivo quantification of the shear modulus of the human Achilles tendon during passive loading using shear wave dispersion analysis","volume":"61","author":"Helfenstein-Didier","year":"2016","journal-title":"Physics in Medicine and Biology"},{"key":"10.7717\/peerj.19581\/ref-26","doi-asserted-by":"publisher","first-page":"1393","DOI":"10.1007\/s00421-017-3629-6","article-title":"Oral contraceptive pill use and the susceptibility to markers of exercise-induced muscle damage","volume":"117","author":"Hicks","year":"2017","journal-title":"European Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-27","doi-asserted-by":"publisher","first-page":"111585","DOI":"10.1016\/j.jbiomech.2023.111585","article-title":"Muscle-tendon unit design and tuning for power enhancement, power attenuation, and reduction of metabolic cost","volume":"153","author":"Holt","year":"2023","journal-title":"Journal of Biomechanics"},{"key":"10.7717\/peerj.19581\/ref-28","doi-asserted-by":"publisher","first-page":"125","DOI":"10.1249\/JES.0000000000000049","article-title":"Elastography for muscle biomechanics: toward the estimation of individual muscle force","volume":"43","author":"Hug","year":"2015","journal-title":"Exercise and Sport Sciences Reviews"},{"key":"10.7717\/peerj.19581\/ref-29","doi-asserted-by":"publisher","first-page":"2610","DOI":"10.1249\/MSS.0000000000002073","article-title":"Methodological recommendations for menstrual cycle research in sports and exercise","volume":"51","author":"Janse\u00a0de Jonge","year":"2019","journal-title":"Medicine and Science in Sports and Exercise"},{"key":"10.7717\/peerj.19581\/ref-30","article-title":"JASP","author":"JASP\u00a0Team","year":"2024"},{"key":"10.7717\/peerj.19581\/ref-31","first-page":"41","article-title":"Metabolic activity and collagen turnover in human tendon in response to physical activity","volume":"5","author":"Kjaer","year":"2005","journal-title":"Journal of Musculoskeletal & Neuronal Interactions"},{"key":"10.7717\/peerj.19581\/ref-32","doi-asserted-by":"publisher","first-page":"111","DOI":"10.1111\/j.1748-1716.2007.01714.x","article-title":"Region specific patellar tendon hypertrophy in humans following resistance training","volume":"191","author":"Kongsgaard","year":"2007","journal-title":"Acta Physiologica"},{"key":"10.7717\/peerj.19581\/ref-33","doi-asserted-by":"publisher","first-page":"155","DOI":"10.1016\/j.jcm.2016.02.012","article-title":"A guideline of selecting and reporting intraclass correlation coefficients for reliability research","volume":"15","author":"Koo","year":"2016","journal-title":"Journal of Chiropractic Medicine"},{"key":"10.7717\/peerj.19581\/ref-34","doi-asserted-by":"publisher","first-page":"25","DOI":"10.1046\/j.1365-201X.2003.01097.x","article-title":"Effect of low-load resistance training on the tendon properties in middle-aged and elderly women","volume":"178","author":"Kubo","year":"2003","journal-title":"Acta Physiologica"},{"key":"10.7717\/peerj.19581\/ref-35","doi-asserted-by":"publisher","first-page":"48","DOI":"10.3109\/03093640309167976","article-title":"The effect of subcutaneous fat on myoelectric signal amplitude and cross-talk","volume":"27","author":"Kuiken","year":"2003","journal-title":"Prosthetics and Orthotics International"},{"key":"10.7717\/peerj.19581\/ref-36","doi-asserted-by":"publisher","first-page":"e10663","DOI":"10.7717\/peerj.10663","article-title":"Effects of subjective and objective autoregulation methods for intensity and volume on enhancing maximal strength during resistance-training interventions: a systematic review","volume":"9","author":"Larsen","year":"2021","journal-title":"PeerJ"},{"key":"10.7717\/peerj.19581\/ref-37","doi-asserted-by":"publisher","first-page":"1250","DOI":"10.1152\/japplphysiol.00823.2014","article-title":"Estrogen inhibits lysyl oxidase and decreases mechanical function in engineered ligaments","volume":"118","author":"Lee","year":"2015","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-38","doi-asserted-by":"publisher","first-page":"e0205782","DOI":"10.1371\/journal.pone.0205782","article-title":"An 8-week resistance training protocol is effective in adapting quadriceps but not patellar tendon shear modulus measured by shear wave elastography","volume":"14","author":"Mannarino","year":"2019","journal-title":"PLOS ONE"},{"key":"10.7717\/peerj.19581\/ref-39","doi-asserted-by":"publisher","first-page":"e0197852","DOI":"10.1371\/journal.pone.0197852","article-title":"Gender associated muscle\u2013tendon adaptations to resistance training","volume":"13","author":"McMahon","year":"2018","journal-title":"PLOS ONE"},{"key":"10.7717\/peerj.19581\/ref-40","doi-asserted-by":"publisher","first-page":"1813","DOI":"10.1007\/s40279-020-01319-3","article-title":"The effects of menstrual cycle phase on exercise performance in eumenorrheic women: a systematic review and meta-analysis","volume":"50","author":"McNulty","year":"2020","journal-title":"Sports Medicine"},{"key":"10.7717\/peerj.19581\/ref-41","doi-asserted-by":"publisher","first-page":"111558","DOI":"10.1016\/j.jbiomech.2023.111558","article-title":"Supersonic shear wave elastography of human tendons is associated with in vivo tendon stiffness over small strains","volume":"152","author":"Mifsud","year":"2023","journal-title":"Journal of Biomechanics"},{"key":"10.7717\/peerj.19581\/ref-42","first-page":"97","article-title":"The effect of the oral contraceptive pill on the passive stiffness of the human gastrocnemius muscle in vivo","volume":"13","author":"Morse","year":"2013","journal-title":"Journal of Musculoskeletal & Neuronal Interactions"},{"key":"10.7717\/peerj.19581\/ref-43","doi-asserted-by":"publisher","first-page":"1193","DOI":"10.1152\/japplphysiol.00825.2014","article-title":"Ultrasound reveals negligible cocontraction during isometric plantar flexion and dorsiflexion despite the presence of antagonist electromyographic activity","volume":"118","author":"Raiteri","year":"2015","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-44","doi-asserted-by":"publisher","first-page":"676","DOI":"10.1038\/nmeth.2019","article-title":"Fiji: an open-source platform for biological-image analysis","volume":"9","author":"Schindelin","year":"2012","journal-title":"Nature Methods"},{"key":"10.7717\/peerj.19581\/ref-45","article-title":"swepy","author":"Seynnes","year":"2023"},{"key":"10.7717\/peerj.19581\/ref-46","doi-asserted-by":"publisher","first-page":"133","DOI":"10.1152\/japplphysiol.00849.2014","article-title":"Ultrasound-based testing of tendon mechanical properties: a critical evaluation","volume":"118","author":"Seynnes","year":"2015","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-47","doi-asserted-by":"publisher","first-page":"523","DOI":"10.1152\/japplphysiol.00213.2009","article-title":"Training-induced changes in structural and mechanical properties of the patellar tendon are related to muscle hypertrophy but not to strength gains","volume":"107","author":"Seynnes","year":"2009","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-48","volume-title":"World family planning 2022: meeting the changing needs for family planning: contraceptive use by age and method","author":"UN. Population\u00a0Division","year":"2022"},{"key":"10.7717\/peerj.19581\/ref-49","doi-asserted-by":"publisher","first-page":"1432","DOI":"10.1152\/japplphysiol.00816.2012","article-title":"Local administration of growth hormone stimulates tendon collagen synthesis in elderly men","volume":"113","author":"Vestergaard","year":"2012","journal-title":"Journal of Applied Physiology"},{"key":"10.7717\/peerj.19581\/ref-50","doi-asserted-by":"publisher","first-page":"e0150799","DOI":"10.1371\/journal.pone.0150799","article-title":"Effects of heavy strength training on running performance and determinants of running performance in female endurance athletes","volume":"11","author":"Vikmoen","year":"2016","journal-title":"PLOS ONE"},{"key":"10.7717\/peerj.19581\/ref-51","doi-asserted-by":"publisher","first-page":"794","DOI":"10.3389\/fphys.2018.00794","article-title":"Effect of training-induced changes in achilles tendon stiffness on muscle-tendon behavior during landing","volume":"9","author":"Werkhausen","year":"2018","journal-title":"Frontiers in Physiology"},{"key":"10.7717\/peerj.19581\/ref-52","doi-asserted-by":"publisher","first-page":"1885","DOI":"10.1249\/MSS.0000000000000603","article-title":"Effects of increased loading on in vivo tendon properties: a systematic review","volume":"47","author":"Wiesinger","year":"2015","journal-title":"Medicine and Science in Sports and Exercise"},{"key":"10.7717\/peerj.19581\/ref-53","doi-asserted-by":"crossref","first-page":"229","DOI":"10.1097\/00003086-199909000-00030","article-title":"Effect of estrogen on cellular metabolism of the human anterior cruciate ligament","volume":"366","author":"Yu","year":"1999","journal-title":"Clinical Orthopaedics and Related Research"},{"key":"10.7717\/peerj.19581\/ref-54","doi-asserted-by":"publisher","first-page":"268","DOI":"10.1097\/00003086-200102000-00031","article-title":"Combined effects of estrogen and progesterone on the anterior cruciate ligament","volume":"383","author":"Yu","year":"2001","journal-title":"Clinical Orthopaedics and Related Research"},{"key":"10.7717\/peerj.19581\/ref-55","doi-asserted-by":"publisher","first-page":"76","DOI":"10.1093\/humupd\/dmt038","article-title":"The effect of combined oral contraception on testosterone levels in healthy women: a systematic review and meta-analysis","volume":"20","author":"Zimmerman","year":"2014","journal-title":"Human Reproduction Update"}],"container-title":["PeerJ"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/peerj.com\/articles\/19581.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/peerj.com\/articles\/19581.xml","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/peerj.com\/articles\/19581.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/peerj.com\/articles\/19581.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,6,12]],"date-time":"2025-06-12T04:45:52Z","timestamp":1749703552000},"score":1,"resource":{"primary":{"URL":"https:\/\/peerj.com\/articles\/19581"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,6,12]]},"references-count":55,"alternative-id":["10.7717\/peerj.19581"],"URL":"https:\/\/doi.org\/10.7717\/peerj.19581","archive":["CLOCKSS","LOCKSS","Portico"],"relation":{},"ISSN":["2167-8359"],"issn-type":[{"value":"2167-8359","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,6,12]]},"article-number":"e19581"}}