LAUSR

This study exploits changes in paid maternity leave offered by one of the United States' largest employers, the Department of Defense, to estimate the effect of such policies on mothers' leave-taking. Since 2015, the U.S. Marine Corps has shifted its maternity leave policy from 6 to 18 to 12 weeks. Leave expansions increased leave duration, whereas contractions decreased leave taken by active-duty service members. However, the policy changes crowded out other forms of leave: with an increase in maternity leave available, mothers increased use of maternity leave and stopped supplementing with additional annual leave. Although all mothers used the full 6 weeks of leave in the early period, it is the less advantaged mothers-those in the enlisted ranks, first-time mothers, and single mothers-who disproportionately used more of the additional leave than officers, experienced mothers, and married mothers. Pregnant officers, experienced mothers, and single women used less leave than nonpregnant women in the months leading up to birth, but expecting additional post-birth leave did not change average pre-birth leave-taking. Our results highlight the importance of optimally sizing family leave policies and provide evidence that the true cost of such programs may be lower than the raw count of weeks provided by additional maternity leave allowances.