The effects that such factors as wages, welfare policies and access to physicians, family planning clinics and abortion providers have on abortion rates and birthrates are examined in analyses based on 1978-1988 state-level data and longitudinal regression techniques. The incidence of abortion is found to be lower in states where access to providers is reduced and state policies are restrictive. Calculations indicate that decreased access may have accounted for about one-quarter of the 5% decline in abortion rates between 1988 and 1992. In addition, birthrates are elevated where the costs of contraception are higher because access to obstetrician-gynecologists and family planning services is reduced. Economic resources such as higher wages for men and women and generous welfare benefits are significantly and consistently related to increased birthrates; however, even a 10% cut in public assistance benefits would result in only one birth fewer for every 212 women on welfare. Economic factors showed no consistent relationship with abortion rates.