- Beyond a handful of studies examining early-adopting states in the early 1990s, little is known about the causal effects of mandatory waiting periods for abortion. In this study we evaluate the effects of a Tennessee law enacted in 2015 that requires women to make an additional trip to abortion providers for state-directed counseling at least 48 hours before they can obtain an abortion. Our difference-in-differences and synthetic-control estimates indicate that the introduction of the mandatory waiting period caused a 53-69 percent increase in the share of abortions obtained during the second trimester. Our analysis examining overall abortion rates is less conclusive but suggests a reduction caused by the waiting period. To put these estimates into context, we provide back-of-the-envelope calculations on the additional monetary costs that Tennessee's MWP imposes on women seeking abortions.