Maternal Health and the Baby Boom

U.S. fertility rose from a low of 2.27 children for women born in 1908 to a peak of 3.21 children for women born in 1932. It dropped to a new low of 1.74 children for women born in 1949, before stabilizing for subsequent cohorts. We propose a novel explanation for this boom-bust pattern, linking it to the huge improvements in maternal health that started in the mid 1930s. Our hypothesis is that the improvements in maternal health contributed to the mid-twentieth century baby boom and generated a rise in women's human capital, ultimately leading to a decline in desired fertility for subsequent cohorts. To examine this link empirically, we exploit the large cross-state variation in the magnitude of the decline in pregnancy-related mortality and the differential exposure by cohort. We find that the decline in maternal mortality is associated with a rise in fertility for women born between 1921 and 1940, with a rise in college and high school graduation rates for women born in 1933-1950 relative to previous cohorts, and with a decline in fertility for women born in 1941-1950 relative to those born in 1921-1940. The analysis provides new insights on the determinants of fertility in the U.S. and other countries that experienced similar improvements in maternal health.