ST. LOUIS (KMOX) - What would happen if every woman in America could obtain free birth control? Washington University School of Medicine researchers tested that idea and came up with some pretty impressive results.

In a group of more than nine thousand local women, free birth control dropped abortion rates by more than 62 percent and teen birth rates were about one sixth the national average, according to lead researcher Dr. Jeffrey Peipert.

“The big decrease is, we think, is because 1) contraception was very available and at no cost 2) women in this project were using the most effective methods of contraception. 75 percent were using the IUD or the implant,” Peipert said.

Those two forms of contraception had been found in an earlier Washington University study to be 20 times more effective than the pill, patch or ring.

Peipert says the abortion rate for women in this study was 4 to 8-per-thousand, compared to the US rate of 20-per-thousand. The teen birth rate fell from 34-per-thousand nationally to just 6-per-thousand in this study. There was also a reduction in the need for repeat abortions.