A Decrease in Sex Ratio at Birth Nine Months after the Earthquake in L'Aquila

Introduction. Multiple factors influence the secondary sex ratio (SSR) including stress, which appears to affect mainly the males born. Objective. We evaluate the effects of the earthquake in L'Aquila on the SSR. Materials and Methods. The SSR for the first six months of 2010 was compared to that of the same period of 2008. The chi-square test and Fisher's test were used for the statistical analysis. Results. Nine months after the earthquake, an important reduction in the SSR was recorded: January 2010 versus January 2008 =0.62 versus 0.96. An overall fall in the SSR was also recorded when the first 3 months of 2010 were compared to the first three months of 2008: 0,82 versus 1,11. When the first three months of 2010 were compared with the second three months of 2010, a statistically significant increase of the sex ratio at birth was noted (0,82 versus 1,27).