There may be fewer obstetrician/gynecologists performing abortions than previously estimated, researchers said.

Just 14% of those who responded to a brief survey said they do the procedure, a smaller figure than the 22% measured by another recent survey, Debra Stulberg, MD, of the University of Chicago, and colleagues reported in the September issue of Obstetrics & Gynecology.

"Access to abortion remains limited by the willingness of physicians to provide abortion services, particularly in rural communities in the South and Midwest," they wrote.

In the U.S., the demand for abortion is high, they said, given that half of pregnancies are unintended, and half of those end in abortion. Yet access remains a challenge for several reasons.

Religious objections may play a role, as may a reduction in training for the procedure in residency programs from the late 1970s through 1996. After that time, abortion training was required for residency.

So to estimate the current prevalence of abortion provision among practicing ob/gyns in the U.S., the researchers conducted a national probability sample mail survey of 1,800 practitioners, with a final sample of 1,031 providers.

Key variables that the researchers asked about included whether respondents had ever encountered patients seeking abortions in their practices, and whether they provided abortion services.

Overall, 97% said they had encountered patients seeking abortions, but only 14.4% said they performed the service.

Female specialists were about 2.5 times more likely than males to provide abortions (18.6% versus 10.6%, OR 2.54, 95% CI 1.57 to 4.08), as were younger practitioners, ages 35 and under (22%).

However, those ages 56 to 65 were the next most likely group to provide abortions; those ages 35 to 45 were the least likely.

There were geographic relationships for abortion provision. Clinicians in the Northeast or West, and in highly urban postal codes, were more likely to do the procedure than those in the South and Midwest or more rural areas, the researchers found.

Stulberg and colleagues wrote that providers living in rural areas, especially in the South and Midwest, may be less likely to provide the service, even if they don't personally object to it, because of opposition in the community. Many try to avoid being a target of antiabortion activists, the researchers said.

They also found that practitioners who identify as being Jewish were more likely to perform abortion (OR 3.27, 95% CI 1.54 to 6.93).

Catholics and Evangelical Protestants, on the other hand, as well as physicians with high religious motivation, were less likely to offer the service, they said.

Stulberg and colleagues concluded that while the decline in the number of abortion providers has slowed in recent years, the 14% estimate of those who do perform it is lower than previously estimated -- notably, a 2008 survey that put the rate at 22%.

That may represent a true decline, they wrote, or it may reflect different sampling and survey techniques.

They also cautioned that their study didn't assess whether specialists who do not perform abortions refer their patients out to colleagues who do. The study was also limited by self report, and by the lack of anonymity involved in reporting and returning the survey.