Agradecimentos: We would like to express aour gratitude to the remaining members of the REBRACO Study Group: Silvana F Bento, Carolina C Ribeiro-do-Valle, Adriana G Luz, Giuliane J Lajos, Fernanda G Surita, Guilherme M Nobrega, Thayna B Griggio, Carla Silveira, Maria J Miele, Ricardo P Tedesco, Karayna G Fernandes, Sérgio HA Martins-Costa, Frederico JA Peret, Francisco E Feitosa, Rosiane Mattar, Evelyn Traina, Edson V Cunha Filho, Janete Vettorazzi, Samira M Haddad, Carla B Andreucci, José P Guida, Mario D Correa Junior, Marcos AB Dias, Leandro G Oliveira, Elias F Melo Junior, Marília GQ da Luz, Sherly Metelus, Lester Castro, Stephanie Pabon, Rachel Soeiro, Amanda D Silva, Paulo S R Junior, Thais G Sardinha, Rodolfo R Japenga, Erica R F Urquiza, Maíra R Machado, Marcela Maria Simões, Larissa M Solda, Sue Yazaki-Sun, Priscilla Mota, Arimaza C Soares, Ellen Machado, Anne Bergmann, Gustavo Raupp dos Santos, Patrícia B Peres, Cristiane L Arbeli, Rafael M Quevedo, Carolina F Yamashita, Julia D Corradin, Isabella Bergamini, José Geraldo L Ramos, Maria Lúcia R Oppermann, Laisa S Quadro, Lina Marins, Érika V Paniz, Thaís Vicentini Xavier, Bruna E Parreira, Aline Tosetto, Sabrina Savazoni, Aline C Costa, Marina HL Almeida, Bruna FV Moura, Lidiane R França, Hanna Vieira, Rafael B Aquino, Débora F Leite, Isabella Monteiro, Marcos Nakamura-Pereira, Bruna O Guerra, Gabriela Gorga, Daisy Pinheiro, Denise Cordeiro, Priscila L Miná, Carol Dornellas, Kevin FA Oliveira, Caio Leal, Rayra Amana, Cristiane O Santos, Marina M dos Santos, Carlos Neto, Thiago Gomes, Isabela R Pereira, Clélia Andrade Salustrino, Valéria B Pontes, Roberto Allen da Silva Franco, João Paolo Bilibio, Gislânia P F Brito, Hana Paula C Pinto, Danielle Leal de Oliveira, Andrezza A Guerra, Andrea O Moura, Natasha Pantoja, Fernanda David, Alina Silva, Juliana Vasconcellos Freitas-Jesus, Rachel Esteves Soeiro, Angela M Bacha, Anderson BorovacPinheiro, Belmiro G Pereira, Eliana M Amaral, Elton Ferreira, Helaine MBPM Milanez, Jamil P S Caldas, Luiz F Baccaro, Marcelo Nomura, Patrícia M Rehder, Renata Z Simone, Renato Passini Jr, João L P Modena, Magnun N Nunes dos Santos, Sergio T M Marba and Tábata R Zumpano dos Santos Ver menos

Abstract: The SARS-CoV-2 (COVID-19) pandemic impacted the health systems between and within countries, and sexual and reproductive health (SRH) services were the most disrupted. Findings from high-income settings have reported significant changes in preterm birth (PTB) prevalence during the pandemic period. Our goal was to assess the PTB rates at the Brazilian national level during the COVID-19 pandemic year 2020 compared to three previous years.Methods: We conducted a population-based cross-sectional study including data from January 2017 to December 2020. We extracted individual-level live birth data from the Brazilian Live Birth Information System (SINASC), which includes all live births from 22 weeks of pregnancy. The main outcome was the PTB rate. We estimated the odds ratio (OR) of PTB using propensity score weighting analysis. In addition to the analysis for the country, we performed a stratified analysis by region. Two-sided p-value of < 1% (0.01) was considered significant. All statistical analysis was conducted using statistical packages in python 3.9 languages.Findings: The prevalence of preterm birth had a higher significant variation within Brazilian regions in 2020 compared to the pre-pandemic period (2017-2019). In Brazil, the OR of preterm births increased by 5.6% (OR: 1.052; 95% CI [1.044; 1.059]). Among the preterm births, the chance of childbirth by caesarean delivery also increased in the pairwise 2019-2020 (OR: 1.121; 95% CI [1.112 - 1.130]).Interpretation: The OR of preterm birth increased during the first year of the COVID-19 pandemic in Brazil. Among the preterm births, the chance of childbirth by caesarean delivery was higher in 2020 than in previous years, suggesting a provider-initiated PTB.Funding: SRH, part of the UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction, a cosponsored programme executed by the World Health Organisation.Funding Information: This work was supported by SRH, part of the UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction, a cosponsored programme executed by the World Health Organisation. Declaration of Interests: The authors declare that they have no conflict of interest.Ethics Approval Statement: This study was part of the REBRACO initiative, and the study protocol was approved by the Institutional Review Board (Letters of Approval numbers 4.047.168) Ver menos