Yet another study has confirmed a fact that seems like basic common sense: Women who have easy access to contraception are considerably less likely to experience unintended pregnancies and, consequently, abortions.

While the Centers for Disease Control and Prevention concluded earlier this year that the rate of unplanned pregnancy and abortion in the U.S. have fallen primarily due to contraceptive use, a new study released from the Washington University School of Medicine this week found that providing free birth control to women increases that effect.

According to a four-year study of more than 9,200 low-income women in the St. Louis area, some of whom lacked insurance coverage, women will choose more-effective, long-lasting forms of contraception – and as a result, experience far fewer unplanned pregnancies – when they are not prohibited by cost. In fact, researchers found that birth rate among teens who received free birth control were less than a fifth of the national birth rate (6.3 births per 1,000 teens compared to 34.3 per 1,000 teens nationwide in 2010), while abortion rates were less than half of the regional and national rates.

The finds come as the Obama administration’s healthcare reform law is poised to offer similar, co-pay free contraception coverage for women. The provision has been bitterly contested by conservatives who claim it violates the religious liberty of employers who do not believe in contraception use.

When price was not a concern the researchers found women typically chose implanted contraceptive options, such as an IUD, which usually cost hundreds of dollars up-front to insert.

"As a society, we want to reduce unintended pregnancies and abortion rates. This study has demonstrated that having access to no-cost contraception helps us get to that goal,” Alina Salganicoff, director of women's health policy at the Kaiser Family Foundation, told the Associated Press.

The Affordable Care Act requires that Food and Drug Administration-approved contraceptive be made available free for women enrolled in most workplace health insurance plans. That change will be in effect for new plans that begin on Jan. 1.

The Washington University study is only the latest to conclude that educating women about reproductive health is the surest way to reduce unwanted pregnancies and, ultimately, abortion. And yet, Republican-led states across the nation continue to champion abstinence-only sex education programs that do not educate young adults about birth control options.

The CDC reports teen pregnancies are highest in states with abstinence-only education policies that typically implore young adults to abstain from sexual activity until marriage. But paradoxically, abstinence-only strategies can actually deter contraception use among teenagers (who are just as likely to have sex), thus increasing their risk for unwanted pregnancies and abortion.