"Surprisingly, little research has looked directly at the impact of Roe v Wade on births. The work that has been done has focused on the experience of those states that legalized abortion prior to Roe. However, the experience of these states may result in a misleading impression of the impact of Roe for several reasons. First, since abortion as already effectively legalized in a handful of states, the effect of Roe may have been less pronounced than the effect of initial legalization because many women were already traveling across state lines to receive abortions. Second, women in states where abortion as not legalized until the 1973 court decision may have been less likely to make use of abortion services, even if they were available, than women ins states that chose to legalize abortion earlier Third, many of the evaluations of legalization simply y compared birth rates before and after legalization, thereby conflating the effect of abortion legalization with ongoing declines in fertility around that time that may have been attributable to changes in the availability of contraception, shifts in social attitudes, improved labor market opportunities for women, and the like."