The “Quiet Revolution” and Cesarean Section in the United States

The U.S. cesarean rate has risen dramatically in the last two generations, from 6% of all births in 1970 to 32% in 2015, an increase that remains imperfectly understood. During this same time period the world of women underwent a “Quiet Revolution” (Goldin, 2006), with dramatic changes in women’s education, labor market attachment, pay, and family formation. This paper explores the extent to which these two phenomena are related. Using the most detailed U.S. survey of birthing mothers available, the National Maternal and Infant Health Survey (NMIHS), we provide the first comprehensive, national analysis of how labor market and family-related factors affect cesarean use. Applying the results to forty-five years of the March Supplement to the Current Population Survey and other data, we then calculate the degree to which these factors contributed to the increase in cesarean rates over the period 1968-2015.

These factors’ relevance is motivated by the idea that health capital is accumulated via investments of money, time, and knowledge. Healthier women should be less likely to require a cesarean delivery. Maternal employment lowers the time invested in health capital, while income and education increase the financial and knowledge base that can be used to develop health capital during pregnancy. These effects should persist even after accounting for health insurance coverage.

Evidence on these points is provided via a regression analysis of the NMIHS. The empirical findings support the theory. Maternal employment substantially increases the probability of receiving a cesarean, especially for first time mothers. Compared to a “low labor market attachment” mother who has never worked, a “high attachment” mother who works both during and after her pregnancy is ten percentage points more likely to receive a cesarean, ceteris paribus. The effect of income is negative, as expected, though not significantly so. In contrast, more educated women have more cesareans (because they have larger, healthier fetuses).

Overall, then, the increases in maternal education and employment that are associated with the Quiet Revolution have led to an increase in the rate of cesarean delivery. Changes in family structure have had the same effect. Delays in family formation, reductions in household size, and the increased absence of the father, all of which accompanied the Quiet Revolution, all increase the rate of cesarean section.

To quantify how much changes in these factors have increased the cesarean rate, these regression estimates are applied to the means of labor market and demographic variables for new mothers in each of the years 1968-2015. From this one can calculate the aggregate effect of all factors, or of any given subset of factors, on cesarean utilization over this period. About one-third of the rise in cesarean rates over this period can be explained by the factors discussed here, especially increased maternal age and decreased family size. Escalated rates of cesarean delivery are, to a substantial degree, a consequence of the Quiet Revolution.