Sporting tournaments and changed birth rates 9 months later: a systematic review

Introduction Emerging evidence suggests that major sporting tournaments are associated with increased birth rates 9 months afterwards. This increase has been attributed to the celebratory atmosphere encouraging more conception through increased sexual activity among the populace. Methods Studies that examined the relationship between a major sporting tournament and altered birth metrics (number of births and/or birth sex ratio, defined as male divided by total live births) 9({+/-}1) months later were sought out systematically through searches of PubMed and Scopus. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed in conducting this study. Results Six major sporting tournaments were linked to noticeably increased birth metrics 9({+/-}1) months later. The Super Bowl (increased United States birth sex ratio in multiple years, however, from 2004 to 2013 there were no observable birth increases in winning counties and losing was not associated with a changed number of births), the 2009 UEFA Champions League (16% increase in Solson&eacutes and Bages births in Spain), the 2010 FIFA World Cup (increased birth sex ratio and over 1000 extra births in South Africa), the 2016 UEFA Euros (2% increase in Northern Ireland births) and the 2019 Rugby World Cup (increased birth sex ratio in some Japanese prefectures). Nine months after the most popular provincial la Liga soccer teams unexpectedly lost matches, there were 0.8% fewer births in those provinces from 2001 to 2015; the number of births were unaffected by unexpected wins. After the 1998 FIFA World Cup a changed sex ratio at birth was not witnessed 9 months on. Nine months following a performance improvement of one standard deviation by a European national soccer team at the FIFA World Cup or UEFA Euro Championships, from 1960 to 2016, there was a 0.3% decline in births 9 months on. Conclusions With a few exceptions, major American football, Association football (soccer) and Rugby apex tournaments in Africa, North America, Asia and Europe were associated with increases in the number of babies born and/or in the birth sex ratio 9({+/-}1) months following notable team wins and/or hosting the tournament. Related to this, unexpected losses by teams from a premier soccer league were associated with a decline in births 9 months on. In conclusion, Nelson Mandela was correct when he averred, "Sport has the power to change the world. It has the power to inspire, it has the power to unite people in a way that little else does."