Do Longer Maternity Leaves Affect Maternal Health?

Featured in print Bulletin on Aging & Health

Half of all mothers of infants in the US work outside of the home, with most of them returning to work by the third month. Recent research suggests that longer maternity leaves may benefit infant health and development - children whose mothers take longer leaves have been found to have lower mortality rates and higher test scores. Yet little is known about the effect of longer maternity leaves on the physical and mental health of mothers.

This question is of definite interest to policymakers. When the Family and Medical Leave Act of 1993 (FMLA) passed, one of its goals was to help new parents balance the demands of work and family by allowing them to take up to twelve weeks of unpaid leave. The act might be expected to have had beneficial effects on the mental and physical health of postpartum women, yet a decade later, it remains an open question whether there was such an effect. Furthermore, several states have recently passed or are considering legislation that would require businesses to provide paid family leave. These laws would likely result in longer maternity leaves at some cost to businesses, employees, and states, and it is difficult to evaluate such laws unless one can weigh the costs against the benefits, including any maternal health benefits.

In Does the Length of Maternity Leaves Affect Maternal Health? (NBER Working Paper 10206), Pinka Chatterji and Sara Markowitz explore whether mothers who return to work later have better mental and physical health. The data for their analysis is the National Maternal and Infant Health Survey, which includes data on prenatal care and postpartum outcomes for a sample of about 1,800 women who had live births and returned to work in 1988. The authors use the well-known Center for Epidemiologic Studies Depression Scale (CES-D) to measure mental health and the number of maternal postpartum outpatient visits to measure overall physical and mental health.

One difficulty in studying this question is that maternal health may affect the decision to return to work and returning to work may affect maternal health, making it difficult to isolate the causal effect of length of maternity leave on health. To surmount this problem, the authors make use of the fact that prior to passage of the FMLA, the states had different maternity leave laws. The authors are able to predict the length of a mother's maternity leave based on the generosity of her state's leave law and other factors unrelated to her health, such as local economic conditions. In their analysis, they estimate the relationship between their predicted length of maternity leave measure for each mother and her physical and mental health.

The authors find that returning to work later is associated with a reduction in the CES-D scale. This means that mothers who return to work later are reporting fewer symptoms of depression, such as "my sleep was restless" or "I could not get going," or are experiencing such symptoms with less frequency or both. Somewhat surprising, however, returning to work later is not associated with a decrease in the probability of being clinically depressed, as measured by reaching a threshold value on the CES-D scale. The authors reconcile these findings by showing that returning to work later is beneficial for women in relatively good mental health, but less so for severely depressed women.

The authors' analysis also suggests that the biggest improvements in mental health come from increasing the length of the maternity leave from under eight weeks to eight to twelve weeks; additional gains from extending maternity leave beyond twelve weeks are substantially smaller. Finally, the authors find that returning to work later is associated with only a very small reduction in the probability of having at least three postpartum outpatient visits.

The authors conclude that policies that encourage longer maternity leaves may reduce depressive symptoms among employed mothers, but that there is no evidence that longer maternity leaves reduce the number of cases of clinical depression or affect overall physical and mental health as measured by the number of outpatient visits.