The Rise and Fall of Excess Male Infant Mortality

Greg L. Drevenstedt, University of Southern California
Eileen Crimmins, University of Southern California
Sarinnapha Vasunilashorn, University of Southern California
Caleb E. Finch, University of Southern California

A nearly universal female advantage in mortality has been well-documented. We use data from fifteen countries to document a remarkably consistent pattern of sex differences in infant mortality over time. Data for Sweden show 10% higher infant mortality among males, which increases to 20% around 1900. Data for other European countries conform to the 19th century pattern. The male disadvantage in infant mortality increased during the 20th century as overall mortality declined rapidly. It reached a peak in the second half of the 20th century in the U.S. and many European countries, but has declined in recent decades. Although lifestyle factors such as smoking contributed to widening adult sex mortality differences, these factors are more questionable at the youngest ages. We test hypotheses that reduced exposure to infection, increased maternal nutrition, and changes in birth practices contributed to observed changes in sex differences in infant mortality.