{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,10]],"date-time":"2026-03-10T02:20:33Z","timestamp":1773109233070,"version":"3.50.1"},"reference-count":40,"publisher":"BMJ","issue":"1","license":[{"start":{"date-parts":[[2026,3,9]],"date-time":"2026-03-09T00:00:00Z","timestamp":1773014400000},"content-version":"unspecified","delay-in-days":67,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"name":"A Better Start National Science Challenge","award":["UOAX1901"],"award-info":[{"award-number":["UOAX1901"]}]},{"name":"Otago Medical School (Dunedin), University of Otago","award":["Not applicable"],"award-info":[{"award-number":["Not applicable"]}]},{"name":"Istar Ltd","award":["Not applicable"],"award-info":[{"award-number":["Not applicable"]}]},{"DOI":"10.13039\/501100009477","name":"Lottery Health Research","doi-asserted-by":"publisher","award":["R-LHR-2021-152823"],"award-info":[{"award-number":["R-LHR-2021-152823"]}],"id":[{"id":"10.13039\/501100009477","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001505","name":"Health Research Council of New Zealand","doi-asserted-by":"publisher","award":["HRC 20\/115"],"award-info":[{"award-number":["HRC 20\/115"]}],"id":[{"id":"10.13039\/501100001505","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001505","name":"Health Research Council of New Zealand","doi-asserted-by":"publisher","award":["HRC 20\/116"],"award-info":[{"award-number":["HRC 20\/116"]}],"id":[{"id":"10.13039\/501100001505","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["bmjph"],"accepted":{"date-parts":[[2026,1,26]]},"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Pregnancy rates amongst users of combined oral contraceptives (COCs) in Aotearoa New Zealand (Aotearoa\/NZ) are unknown. Filling this gap aims to help guide future research and initiatives for achieving equitable contraceptive services in Aotearoa\/NZ.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To estimate the rate of pregnancy among users of COCs in Aotearoa\/NZ in 2019, and explore correlates of pregnancy rate across sociodemographic and geographic factors.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This retrospective cohort study used whole-of-population data from the Integrated Data Infrastructure, a research database containing deidentified routinely collected government data. Users of COCs were identified using pharmaceutical dispensing data, and pregnancy events were identified in maternity and hospital discharge datasets. Pregnancy events were included if they were estimated to have been conceived during a period of COC use. Observed pregnancy rates were calculated for the entire study population, new and established users, and sociodemographic and geographic subgroups. Rates were analysed using Poisson regression models to produce comparative risk ratios and 95% CIs that were adjusted for covariates.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A pregnancy rate of 3.50 per 100 person-years of COC use was identified from a cohort of 208\u2009197 individuals using COCs in Aotearoa\/NZ in 2019. There was significant variation in pregnancy rates by several key sociodemographic and geographic factors including by whether a user was new\/restarting or established (reference) on COCs (adjusted risk ratio 1.28, 95%\u2009CI 1.19 to 1.37), or lived in a rural or urban (reference) area (adjusted risk ratio 1.32, 95%\u2009CI 1.21 to 1.44). There were also significant differences in pregnancy rate by age group, ethnicity, parity, highest qualification, household income, and neighbourhood deprivation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The estimated pregnancy rate among users of COCs in Aotearoa\/NZ is comparable to international findings. Sociodemographic and geographic variation in pregnancy rates may be explained by inconsistent pill use, access barriers, contraceptive failure, and early discontinuation of COCs with intended pregnancy conception. An opportunity remains for further research to fully understand the drivers of such variation. Nevertheless, these findings will inform family planning services, clinical practice, and public health policy. Furthermore, they have implications for whether healthcare services are providing equitable contraceptive care and meeting the needs of contraceptive users.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjph-2025-003252","type":"journal-article","created":{"date-parts":[[2026,3,9]],"date-time":"2026-03-09T14:35:24Z","timestamp":1773066924000},"page":"e003252","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Pregnancy rates among users of combined oral contraceptives in Aotearoa New Zealand in 2019: a nationwide retrospective cohort study"],"prefix":"10.1136","volume":"4","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3837-5476","authenticated-orcid":false,"given":"Caryn","family":"Thomas","sequence":"first","affiliation":[{"name":"Department of Obstetrics, Gynaecology, and Women\u2019s Health | Oranga W\u0101hine, University of Otago, Dunedin, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicholas","family":"Bowden","sequence":"additional","affiliation":[{"name":"Department of Paediatrics and Child Health, University of Otago, Dunedin, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rhiannon","family":"Braund","sequence":"additional","affiliation":[{"name":"Pharmacy and Biomedical Sciences, Te Huataki Waiora - School of Health, The University of Waikato, Hamilton, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jesse","family":"Kokaua","sequence":"additional","affiliation":[{"name":"Va\u2019a o Tautai - Centre for Pacific Health, Division of Health Sciences, University of Otago, Dunedin, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Matthew","family":"Hobbs","sequence":"additional","affiliation":[{"name":"Faculty of Health, University of Canterbury, Christchurch, Canterbury, New Zealand"},{"name":"GeoHealth Laboratory, Geospatial Research Institute, University of Canterbury, Christchurch, Canterbury, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8240-082X","authenticated-orcid":false,"given":"Helen","family":"Paterson","sequence":"additional","affiliation":[{"name":"Department of Obstetrics, Gynaecology, and Women\u2019s Health | Oranga W\u0101hine, University of Otago, Dunedin, New Zealand"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2026,3,9]]},"reference":[{"key":"2026030907351551000_4.1.e003252.1","doi-asserted-by":"crossref","first-page":"S42","DOI":"10.3109\/13625187.2010.533002","article-title":"Contraceptive use and behavior in the 21st century: a comprehensive study across five European countries","volume":"15 Suppl 2","author":"Skouby","year":"2010","journal-title":"Eur J Contracept Reprod Health Care"},{"key":"2026030907351551000_4.1.e003252.2","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.contraception.2016.03.011","article-title":"Typical-use contraceptive failure rates in 43 countries with Demographic and Health Survey data: summary of a detailed report","volume":"94","author":"Polis","year":"2016","journal-title":"Contraception"},{"key":"2026030907351551000_4.1.e003252.3","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1111\/ajo.13672","article-title":"Disparities in utilisation of combined oral contraceptives in Aotearoa New Zealand: A cross-sectional whole-of-population study","volume":"63","author":"Thomas","year":"2023","journal-title":"Aust N Z J Obstet Gynaecol"},{"key":"2026030907351551000_4.1.e003252.4","unstructured":"Ministry of Health . 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Contraception: which option for which patient?. 2021."},{"key":"2026030907351551000_4.1.e003252.18","unstructured":"Sexual Wellbeing Aotearoa NV . Combined oral contraceptive pill. sex. wellbeing aotearoa. Available: https:\/\/sexualwellbeing.org.nz\/adv\/contraception\/combined-oral-contraceptive-pill\/ [Accessed 30 Nov 2025]."},{"key":"2026030907351551000_4.1.e003252.19","doi-asserted-by":"publisher","DOI":"10.1093\/ije\/dyz014"},{"key":"2026030907351551000_4.1.e003252.20","unstructured":"Integrated data infrastructure (IDI) refresh: linking report: methods and design, October 2023 refresh. Wellington Stats NZ Tatauranga Aotearoa; 2023."},{"key":"2026030907351551000_4.1.e003252.21","unstructured":"Ryall T . Health and disability services eligibility direction. 2011."},{"key":"2026030907351551000_4.1.e003252.22","doi-asserted-by":"publisher","DOI":"10.1097\/01.AOG.0000239122.98508.39"},{"key":"2026030907351551000_4.1.e003252.23","doi-asserted-by":"publisher","DOI":"10.1097\/AOG.0b013e3182056309"},{"key":"2026030907351551000_4.1.e003252.24","unstructured":"National Health Board Business Unit . National Maternity Collection Data Mart Data Dictionary. Wellington: Ministry of Health, 2011."},{"key":"2026030907351551000_4.1.e003252.25","unstructured":"Ministry of Health . HISO 10001:2017 ethnicity data protocols. 2017."},{"key":"2026030907351551000_4.1.e003252.26","unstructured":"Atkinson J , Salmond C , Crampton P . NZDep2018 index of deprivation. Wellington University of Otago; December 2020."},{"key":"2026030907351551000_4.1.e003252.27","first-page":"24","article-title":"Defining rural in Aotearoa New Zealand: a novel geographic classification for health purposes","volume":"135","author":"Whitehead","year":"2022","journal-title":"N Z Med J"},{"key":"2026030907351551000_4.1.e003252.28","doi-asserted-by":"crossref","first-page":"908","DOI":"10.1093\/ije\/dyaa043","article-title":"Area-level deprivation, childhood dental ambulatory sensitive hospitalizations and community water fluoridation: evidence from New Zealand","volume":"49","author":"Hobbs","year":"2020","journal-title":"Int J Epidemiol"},{"key":"2026030907351551000_4.1.e003252.29","unstructured":"SAS . Cary, NC, USA SAS Institute Inc."},{"key":"2026030907351551000_4.1.e003252.30","unstructured":"Stata statistical software. 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