No-fault divorce laws may have caused a temporary spike in violent crime, researchers said in a released statement on Monday. The findings in a new study evaluated crime rates following the reform in some U.S. states.

Investigators from Universidad Carlos III in Madrid found that on average there was a 9 percent increase in violent crime after a state enacted a unilateral divorce law, which does not require evidence of wrong-doing by either spouse or the consent of both spouses for dissolution of marriage.

The research found that the spike in crime was on average confined to the first two decades after the reform, and was mostly attributed to individuals who were young children at the time the new law was enacted.

The study's authors, economists Julio Cáceres-Delpiano and Eugenio Giolito explained that the link between unilateral reform and crime seems to be poverty and worsening in income.

They wrote that mothers in states endorsing unilateral marriage were more likely to become the head of the household after the reform, and that these families were more likely to experience worse economic conditions compared to financial conditions before divorce leading to an escalation in income inequality.

Researchers examined FBI crime reports between 1965 to 1996 for adopting states in that period and found that the effects of reform, especially in the uptick of divorce rates and other social ills, mainly affected “families trapped in that transition to unilateral divorce” were mainly temporary and dissipated later a decade after reform.

Researchers suggested that the temporary effects could be due to people changing their approach to marriage once the law was enacted.

"Scholars suggest that the reform has caused changes in the selection into and out of marriage, increasing the average match quality of new and surviving marriages," Cáceres-Delpiano and Giolito wrote.

The study is published in the Journal of Labor Economics.