Over the past six years, Colorado has nearly halved its rate of abortions and teen pregnancies with its implementation of the Colorado Family Planning Initiative — a program that offered women long-acting reversible contraceptives (LARCs), free of charge. The results surprised lawmakers and researchers alike, and suggest that the contraceptive pill’s heyday as America’s favorite birth control method may soon come to an end.

In one of the biggest studies of long-acting birth control, more than 30,000 teenagers and disadvantaged women living in Colorado have received free intrauterine devices (IUDs)) and birth control implants since 2009. Since then, the teenage birthrate dropped by 40 percent and the rate of abortion fell by 42 percent, The New York Times reported. Teen abortions have dropped by 34 percent, with results most prominent in some of the poorer areas of the state.

“Our demographer came into my office with a chart and said, ‘Greta, look at this, we’ve never seen this before,’” Greta Klingler, the family planning supervisor for the public health department, told The Times. “The numbers were plummeting.”

Unfortunately, due to funding issues, the six-year-long program was forced to come to an end this June. Still, its results are resounding and may set a precedent for the future of birth control in America. Currently, the birth control pill is the most popular form of birth control used by American women. The most recent figures from the Centers for Disease Control and Prevention found that, among American women between the ages of 15 and 44 who were using contraceptives, 16 percent preferred the birth control pill. The male condom followed in popularity, with 9.4 percent of the women surveyed citing it as their preferred method of birth control. LARCs are currently the third most popular form of birth control among American women.

What’s a LARC?

The term LARC describes both intrauterine devices and birth control implants. These contraceptive methods can both last up to several years but can also be removed at any point if a woman decides she wants to become pregnant. The American Congress of Obstetricians and Gynecologists (ACOG) estimates that fewer than one in 100 women become pregnant during the first year of typical use.

Both devices work by preventing fertilization. Hormone-based IUDs release hormones that work to both prevent sperm from entering the uterus and also prevent the implantation of a fertilized egg. Non-hormone-based IUDs use copper as a natural way to prevent sperm from fertilizing an egg.

The birth control implant is a flexible rod inserted under the skin of the arm and releases hormones into the body which prevent pregnancy.

The ACOG cites that, in typical long-term use, LARCs are up to 20 times more effective than the birth control pill in preventing unplanned pregnancies.

Increasing Popularity

Research shows the LARCs are slowly growing in popularity, especially among the most vulnerable demographic: teenage girls. The number of U.S. teens using IUDs or birth control implants jumped from 0.4 percent in 2005 to 7.1 percent in 2013, LiveScience reported. A CDC report from February 2015 showed that LARC use among women of all child-bearing ages has increased by five-fold.

There are many reasons for women choosing LARC birth control over the pill. For one, the ACOG cites that, in typical long-term use, LARCs are up to 20 times more effective than the birth control pill in preventing unplanned pregnancies. One of the most popular reasons for preference of LARCs is ease. Unlike the birth control pill, LARCs do not require women to remember to do something every day or every time they have sex. One of the biggest hindrances of LARC use is cost. According to NPR, being fitted with one of these devices can cost between $500 to several thousand dollars.

Lawmakers like Republican Colorado State Rep. Don Coram are looking to other sources of funding to restart state-funded programs that would reduce the financial burden of LARC contraceptive use.

“For every dollar that we spent on this, we averted spending $5.85 on social services, on welfare, on hospitalizations. It was just a huge, huge savings,” Coram told NPR in a recent radio interview, adding that, “not doing this program, the abortion rate will certainly go back up. The teen pregnancy rate and, you know, just the cycle of poverty will continue.”