New Mexico will end conjugal visits between inmates and their spouses next month, officials said Wednesday, in a move that will leave the once-widespread practice in place in only three U.S. states.

In addition to addressing concerns over pregnancies, the spread of sexually transmitted diseases, and smuggled contraband, eliminating the program will save the state about $120,000 per year, New Mexico Department of Corrections spokeswoman Alex Tomlin said.

"After two years of research we found the overnight stays had no impact on decreasing the rate of inmates returning to jail," Tomlin said.

The debate over conjugal visits has pitted political conservatives who view the practice as inconsistent with the ethic of punishment against some prison officials who say the visits improve inmate behavior and maintain family bonds, said Stewart J. D'Alessio, a criminal justice professor at Florida International University who has studied the issue.

Once a common practice in U.S. prisons, soon only California, Washington state, and New York state prisons will permit conjugal visits. Federal prisons do not allow them.

Mississippi, the first U.S. state to sanction sex for prisoners, ended its century-old program of conjugal visits in February.

In New Mexico, the change will affect only a small minority of prisoners, Tomlin said, as fewer than 150 of the state's 7,000 inmates currently qualify for conjugal visits.

A 2012 study co-authored by D'Alessio found that prisons in states where conjugal visits are not allowed have more than four times the number of incidents of inmate-on-inmate sexual violence compared to states where the practice is permitted.

[Image: Young Man In Prison via Shutterstock]