Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries
Authors: Calvert Clara , Brockway Meredith , Zoega Helga , Miller Jessica E. , Been Jasper V. , Amegah Adeladza Kofi , Racine-Poon Amy , Oskoui Solmaz Eradat , Abok Ishaya I. , Aghaeepour Nima , Akwaowo Christie D. , Alshaikh Belal N. , Ayede Adejumoke I. , Bacchini Fabiana , Barekatain Behzad , Barnes Rodrigo , Bebak Karolina , Berard Anick , Bhutta Zulfiqar A. , Brook Jeffrey R. , Bryan Lenroy R. , Cajachagua-Torres Kim N. , Campbell-Yeo Marsha , Chu Dinh-Toi , Connor Kristin L. , Cornette Luc , Cortés Sandra , Daly Mandy , Debauche Christian , Dedeke Iyabode Olabisi F. , Einarsdóttir Kristjana , Engjom Hilde , Estrada-Gutierrez Guadalupe , Fantasia Ilaria , Fiorentino Nicole M. , Franklin Meredith , Fraser Abigail , Gachuno Onesmus W. , Gallo Linda A. , Gissler Mika , Håberg Siri E. , Habibelahi Abbas , Häggström Jonas , Hookham Lauren , Hui Lisa , Huicho Luis , Hunter Karen J. , Huq Sayeeda , KC Ashish , Kadambari Seilesh , Kelishadi Roya , Khalili Narjes , Kippen Joanna , Le Doare Kirsty , Llorca Javier , Magee Laura A. , Magnus Maria C. , Man Kenneth K. C. , Mburugu Patrick M. , Mediratta Rishi P. , Morris Andrew D. , Muhajarine Nazeem , Mulholland Rachel H. , Bonnard Livia Nagy , Nakibuuka Victoria , Nassar Natasha , Nyadanu Sylvester D. , Oakley Laura , Oladokun Adesina , Olayemi Oladapo O. , Olutekunbi Olanike A. , Oluwafemi Rosena O. , Ogunkunle Taofik O. , Orton Chris , Örtqvist Anne K. , Ouma Joseph , Oyapero Oyejoke , Palmer Kirsten R. , Pedersen Lars H. , Pereira Gavin , Pereyra Isabel , Philip Roy K. , Pruski Dominik , Przybylski Marcin , Quezada-Pinedo Hugo G. , Regan Annette K. , Rhoda Natasha R. , Rihs Tonia A. , Riley Taylor , Rocha Thiago Augusto Hernandes , Rolnik Daniel L. , Saner Christoph , Schneuer Francisco J. , Souter Vivienne L. , Stephansson Olof , Sun Shengzhi , Swift Emma M. , Szabó Miklós , Temmerman Marleen , Tooke Lloyd , Urquia Marcelo L. , von Dadelszen Peter , Wellenius Gregory A. , Whitehead Clare , Wong Ian C. K. , Wood Rachael , Wróblewska-Seniuk Katarzyna , Yeboah-Antwi Kojo , Yilgwan Christopher S. , Zawiejska Agnieszka , Sheikh Aziz , Rodriguez Natalie , Burgner David , Stock Sarah J. , Azad Meghan B. 
Published: February 2023

Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from −90% to +30%, were reported in many countries following early COVID-19 pandemic response measures (‘lockdowns’). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95–0.98, P value <0.0001), second (0.96, 0.92–0.99, 0.03) and third (0.97, 0.94–1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96–1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88–1.14, 0.98), third (0.99, 0.88–1.12, 0.89) and fourth (1.01, 0.87–1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02–1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03–1.15, 0.002), third (1.10, 1.03–1.17, 0.003) and fourth (1.12, 1.05–1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways.