{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,25]],"date-time":"2026-07-25T05:51:24Z","timestamp":1784958684166,"version":"3.55.0"},"reference-count":43,"publisher":"Oxford University Press (OUP)","issue":"10","license":[{"start":{"date-parts":[[2025,9,1]],"date-time":"2025-09-01T00:00:00Z","timestamp":1756684800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"funder":[{"name":"French Agence Nationale de Recherches sur le SIda et les H\u00e9patite Virales"},{"name":"Maladies Infectieuses Emegentes"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,10,3]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Objectives<\/jats:title>\n                  <jats:p>There have been few studies in pregnant women of medications that are used to reduce severe complications from COVID-19 infection. Currently, nirmatrelvir\/ritonavir (Paxlovid) is recommended by the National Institutes for Health to treat non-hospitalized pregnant patients with mild-to-moderate COVID-19 illness. The aim of this study was to determine the transplacental passage of molnupiravir, nirmatrelvir\/ritonavir and favipiravir utilizing an ex vivo placental perfusion model.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>Human placental cotyledons were continuously perfused in a double open circuit. The study molecules and antipyrine, a marker of placental viability, were dissolved in the maternal solution. The experiment was conducted over 90\u2005minutes, and every 5\u2005minutes, samples of the maternal solution and fetal exchange solutions were collected for analysis. We calculated the concentrations of study molecules, fetal transfer ratios and the clearance indexes to determine placental transfer.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>Of 18 placentas analysed, 14 were validated by antipyrine transfer. Nirmatrelvir alone had low placental transfer, with a fetal transfer ratio of 0.025. Its placenta transfer increased in the presence of ritonavir, with a fetal transfer ratio of 0.06. The molnupiravir metabolite, \u03b2-D-N-4-hydroxycytidine (EIDD 1931), showed low placental transfer, with an average fetal transfer ratio of 0.04. By contrast, favipiravir crossed the placenta with an average fetal transfer ratio of 0.425.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>Placental transfer was high for the nucleoside analogue favipiravir, while it was low for molnupiravir and low for the protease inhibitor nirmatrelvir but increased by ritonavir. Clinical data are required to confirm the placental transfer and determine the safety of COVID antivirals in pregnancy.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/jac\/dkaf302","type":"journal-article","created":{"date-parts":[[2025,9,1]],"date-time":"2025-09-01T14:33:13Z","timestamp":1756737193000},"page":"2807-2813","source":"Crossref","is-referenced-by-count":1,"title":["Placental transfer of medications to treat COVID-19, molnupiravir, favipiravir and nirmatrelvir\/ritonavir, in the <i>ex vivo<\/i> human cotyledon model"],"prefix":"10.1093","volume":"80","author":[{"given":"Solene","family":"Labaye","sequence":"first","affiliation":[{"name":"Assistance Publique-H\u00f4pitaux de Paris, Service de Gyn\u00e9cologie-Obst\u00e9trique, H\u00f4pital Louis Mourier , Colombes ,","place":["France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fatima","family":"Djellali","sequence":"additional","affiliation":[{"name":"Assistance Publique-H\u00f4pitaux de Paris, Service de Gyn\u00e9cologie-Obst\u00e9trique, H\u00f4pital Louis Mourier , Colombes ,","place":["France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4359-537X","authenticated-orcid":false,"given":"Gilles","family":"Peytavin","sequence":"additional","affiliation":[{"name":"Universit\u00e9 Paris Cit\u00e9 , Facult\u00e9 de M\u00e9decine, Paris ,","place":["France"]},{"name":"Inserm IAME 1137 Infection Antimicrobials Modelling Evolution, Paris ,","place":["France"]},{"name":"Assistance Publique-H\u00f4pitaux de Paris, Laboratoire de Pharmacologie-Toxicologie, H\u00f4pital Bichat-Claude Bernard , Paris ,","place":["France"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5883-7597","authenticated-orcid":false,"given":"Laurent","family":"Mandelbrot","sequence":"additional","affiliation":[{"name":"Assistance Publique-H\u00f4pitaux de Paris, Service de Gyn\u00e9cologie-Obst\u00e9trique, H\u00f4pital Louis Mourier , Colombes ,","place":["France"]},{"name":"Universit\u00e9 Paris Cit\u00e9 , Facult\u00e9 de M\u00e9decine, Paris ,","place":["France"]},{"name":"Inserm IAME 1137 Infection Antimicrobials Modelling Evolution, Paris ,","place":["France"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2025,9,1]]},"reference":[{"key":"2025100314251845600_dkaf302-B1","author":"World Health Organization"},{"key":"2025100314251845600_dkaf302-B2","doi-asserted-by":"publisher","first-page":"m3320","DOI":"10.1136\/bmj.m3320","article-title":"Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis","volume":"370","author":"Allotey","year":"2020","journal-title":"BMJ"},{"key":"2025100314251845600_dkaf302-B3","doi-asserted-by":"publisher","first-page":"177","DOI":"10.1016\/j.ajog.2021.08.054","article-title":"An update on COVID-19 and pregnancy","volume":"226","author":"Jamieson","year":"2022","journal-title":"Am J Obstet Gynecol"},{"key":"2025100314251845600_dkaf302-B4","doi-asserted-by":"publisher","first-page":"100107","DOI":"10.1016\/j.ajogmf.2020.100107","article-title":"Outcome of coronavirus spectrum infections (SARS, MERS, COVID-19) during pregnancy: a systematic review and meta-analysis","volume":"2","author":"Di Mascio","year":"2020","journal-title":"Am J Obstet Gynecol MFM"},{"key":"2025100314251845600_dkaf302-B5","doi-asserted-by":"publisher","first-page":"512","DOI":"10.1093\/cid\/ciae580","article-title":"COVID-19 antiviral medication use among pregnant and recently pregnant US outpatients","volume":"80","author":"Regan","year":"2025","journal-title":"Clin Infect Dis"},{"key":"2025100314251845600_dkaf302-B6","volume-title":"Publications & Clinical Guidance","author":"COVID Clinical. 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