Changes in Conception Rates, Not in Pregnancy-Related Behavior, Likely Caused Decline in Pre-Term Births in Developed Countries During the First Year of the COVID-19 Pandemic 11* Corresponding author: Peter Fallesen, peter.fallesen@sofi.su.se, Swedish Institute for Social Research, Stockholm University, Stockholm 106 91, Sweden.Peter Fallesen, PhDSwedish Institute for Social Research, Stockholm University, Stockholm 106 91, Sweden ROCKWOOL Foundation, Ny Kongensgade 6, 1472 Copenhagen C, DenmarkMoritz Oberndorfer, DSc  Institute of Social Medicine, Center for Public Health, Medical University of Vienna, Kinderspitalgasse 15/1. Stock, A-1090, Vienna, Austria; MRC/CSO Social and Public Health Sciences Unit, University of Glasgow, Berkeley Square, 99 Berkeley Street, Glasgow, G3 7HR, UK  Population Research Unit, University of Helsinki, Unioninkatu 35 (P.O. Box 18). 00014 University of Helsinki, Finland