The number of abortions performed in the United States has declined sharply, dropping 12 percent since 2010, according a survey released by the Associated Press.

And, perhaps predictably, the two sides in the abortion debate credit themselves. Antiabortion activists credit new restrictions in many states, while abortion rights supporters credit the contraception mandate in President Obama's health-care law.

Both miss some other huge factors.

What hasn't received as much attention is the rapid rise in the share of women using stay-in-place, constantly active forms of birth control with very low failure rates such as under-the-skin implants and IUDs. In the medical world, these contraceptives are known as “long-acting reversible contraceptives.”

And what has happened with IUDs is particularly interesting.

IUD use reached its peak in the United States in the 1970s, then declined sharply before the devices were removed from the market because of safety concerns. Products that manufacturers and federal regulators declared safe began to return to the U.S. marketplace in 1990 but really took off beginning in the 2000s.

The use of long-acting reversible contraceptives rose from 1.5 percent in 2002 to 7.2 percent in 2011 among girls and women ages 14 to 44, according to the Centers for Disease Control and Prevention's 2011-2013 National Survey of Family Growth -- the most recent data of its kind available. And most of that growth happened because young women opted for IUDs.

Another sizable factor: a sharp decline in teenage pregnancy. In 2013, the most recent year for which detailed federal data is available, there were 26.5 births among every 1,000 teenage girls in the United States. That’s down from a high of 61.8 teen births in 1991. But that decline began nearly 25 years ago. In fact, federal government statisticians say the teenage pregnancy rate actually has been in a state of slow decline since the 1950s. And perhaps more significantly, even the nation’s improved teenage pregnancy rate remains far larger than those of other countries with advanced economies.

These two things aside, with the news about abortions in the headlines, the two sides are eager to point to their own policies.

Abortion clinics nationwide have effectively closed as antiabortion activists have pursued a strategy of state-level regulations restricting access to them, requiring pre-abortion sonograms and waiting periods, creating new credential requirements for doctors who perform the procedures and other measures. In Mississippi, for example, only one abortion clinic remains open in the state. (That same clinic was seriously damaged in March after vandals attacked the facility while it was closed.) Proponents of these laws say they have helped shift the culture to include greater respect for life and prompted more women to carry their pregnancies to term. And to maintain these gains, groups such as Americans United for Life have lobbyists in several states.

At the other end of the spectrum, groups that advocate for access to safe abortions say that an expansion in the availability of free and constantly active, low-failure-rate forms of birth control – such as IUDs – has fundamentally reduced the rate of unintended pregnancy among teenagers and women, therefore lowering the demand for abortion services.

Provisions of the Affordable Care Act that have required insurance companies to cover the full cost of birth control since 2012 have ended the cost challenges that made it difficult for at least 48 million women to manage their fertility, according to a report released by the National Women’s Law Center this year. The cost of contraception was, according to the report, forcing some women to choose between such things as food, rent and birth control.

For what it's worth, the Associated Press’s analysis of national abortion data centers around the fact that abortion rates have dipped in states with new abortion restrictions and those without them at about similar rates. But the National Women's Law Center report also found significant evidence that many insurance plans -- half of the 100 plans in 15 states that the center's staff examined in 2014 and 2015 -- simply have not complied with the Affordable Care Act. (In this case, failure to comply means refusing to cover maternity care, birth control, breast-feeding support and supplies, genetic testing, well-woman visits and prescription drugs or forcing women to share the cost of services for which the Affordable Care Act has mandated full coverage since 2012.)

So it seems that although the Affordable Care Act does deserve some credit, it does not deserve it all. Women -- who have improved access to contraception and have chosen more reliable methods -- probably do.