{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T15:52:48Z","timestamp":1791388368200,"version":"4.3.3"},"reference-count":38,"publisher":"Wiley","issue":"5","license":[{"start":{"date-parts":[[2021,11,1]],"date-time":"2021-11-01T00:00:00Z","timestamp":1635724800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["obgyn.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Ultrasound in Obstet &amp;amp; Gyne"],"published-print":{"date-parts":[[2021,11]]},"abstract":"<jats:title>ABSTRACT<\/jats:title><jats:sec><jats:title>Objective<\/jats:title><jats:p>To investigate the effect of restriction measures implemented to mitigate severe acute respiratory syndrome coronavirus 2 (SARS\u2010CoV\u20102) transmission during the coronavirus disease 2019 (COVID\u201019) pandemic on pregnancy duration and outcome.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>A before\u2010and\u2010after study was conducted with cohort sampling in three maternity hospitals in Melbourne, Australia, including women who were pregnant when restriction measures were in place during the COVID\u201019 pandemic (estimated conception date between 1 November 2019 and 29 February 2020) and women who were pregnant before the restrictions (estimated conception date between 1 November 2018 and 28 February 2019). The primary outcome was delivery before 34\u2009weeks' gestation or stillbirth. The main secondary outcome was a composite of adverse perinatal outcomes. Pregnancy outcomes were compared between women exposed to restriction measures and unexposed controls using the \u03c7\u2010square test and modified Poisson regression models, and duration of pregnancy was compared between the groups using survival analysis.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>In total, 3150 women who were exposed to restriction measures during pregnancy and 3175 unexposed controls were included. Preterm birth before 34\u2009weeks or stillbirth occurred in 95 (3.0%) exposed pregnancies and in 130 (4.1%) controls (risk ratio (RR), 0.74 (95%\u2009CI, 0.57\u20130.96); <jats:italic>P<\/jats:italic>\u2009=\u20090.021). Preterm birth before 34\u2009weeks occurred in 2.4% of women in the exposed group and in 3.4% of women in the control group (RR, 0.71 (95%\u2009CI, 0.53\u20130.95); <jats:italic>P<\/jats:italic>\u2009=\u20090.022), without evidence of an increase in the rate of stillbirth in the exposed group (0.7% <jats:italic>vs<\/jats:italic> 0.9%; RR, 0.83 (95%\u2009CI, 0.48\u20131.44); <jats:italic>P<\/jats:italic>\u2009=\u20090.515). Competing\u2010risks regression analysis showed that the effect of the restriction measures on spontaneous preterm birth was stronger and started earlier (subdistribution hazard ratio (HR), 0.81 (95%\u2009CI, 0.64\u20131.03); <jats:italic>P<\/jats:italic>\u2009=\u20090.087) than the effect on medically indicated preterm birth (subdistribution HR, 0.89 (95%\u2009CI, 0.70\u20131.12); <jats:italic>P<\/jats:italic>\u2009=\u20090.305). The effect was stronger in women with a previous preterm birth (RR, 0.42 (95%\u2009CI, 0.21\u20130.82); <jats:italic>P<\/jats:italic>\u2009=\u20090.008) than in parous women without a previous preterm birth (RR, 0.93 (95%\u2009CI, 0.63\u20131.38); <jats:italic>P<\/jats:italic>\u2009=\u20090.714) (<jats:italic>P<\/jats:italic> for interaction\u2009=\u20090.044). Composite adverse perinatal outcome was less frequent in the exposed group than in controls (all women: 2.1% <jats:italic>vs<\/jats:italic> 2.9%; RR, 0.73 (95%\u2009CI, 0.54\u20130.99); <jats:italic>P<\/jats:italic>\u2009=\u20090.042); women with a previous preterm birth: 4.5% <jats:italic>vs<\/jats:italic> 8.4%; RR, 0.54 (95%\u2009CI, 0.25\u20131.18); <jats:italic>P<\/jats:italic>\u2009=\u20090.116).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>Restriction measures implemented to mitigate SARS\u2010CoV\u20102 transmission during the COVID\u201019 pandemic were associated with a reduced rate of preterm birth before 34\u2009weeks. This reduction was mainly due to a lower rate of spontaneous prematurity. The effect was more substantial in women with a previous preterm birth and was not associated with an increased stillbirth rate. \u00a9 2021 International Society of Ultrasound in Obstetrics and Gynecology.<\/jats:p><\/jats:sec>","DOI":"10.1002\/uog.23743","type":"journal-article","created":{"date-parts":[[2021,7,26]],"date-time":"2021-07-26T14:38:23Z","timestamp":1627310303000},"page":"677-687","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":53,"title":["Impact of <scp>COVID<\/scp>\u201019 pandemic restrictions on pregnancy duration and outcome in Melbourne, Australia"],"prefix":"10.1002","volume":"58","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2263-3592","authenticated-orcid":false,"given":"D. L.","family":"Rolnik","sequence":"first","affiliation":[{"name":"Department of Obstetrics and Gynaecology Monash University  Melbourne Australia"},{"name":"Department of Obstetrics and Gynaecology Women's and Newborn Program, Monash Health  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"Matheson","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynaecology Women's and Newborn Program, Monash Health  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Y.","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynaecology Monash University  Melbourne Australia"},{"name":"Department of Obstetrics and Gynaecology Women's and Newborn Program, Monash Health  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S.","family":"Chu","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynaecology Monash University  Melbourne Australia"},{"name":"Department of Obstetrics and Gynaecology Women's and Newborn Program, Monash Health  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C.","family":"Mcgannon","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynaecology Monash University  Melbourne Australia"},{"name":"Department of Obstetrics and Gynaecology Women's and Newborn Program, Monash Health  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"B.","family":"Mulcahy","sequence":"additional","affiliation":[{"name":"Monash Newborn, Monash Children's Hospital  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9664-4182","authenticated-orcid":false,"given":"A.","family":"Malhotra","sequence":"additional","affiliation":[{"name":"Monash Newborn, Monash Children's Hospital  Melbourne Australia"},{"name":"Department of Paediatrics Monash University  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K. R.","family":"Palmer","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynaecology Monash University  Melbourne Australia"},{"name":"Department of Obstetrics and Gynaecology Women's and Newborn Program, Monash Health  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R. J.","family":"Hodges","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynaecology Monash University  Melbourne Australia"},{"name":"Department of Obstetrics and Gynaecology Women's and Newborn Program, Monash Health  Melbourne Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8337-550X","authenticated-orcid":false,"given":"B. 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