Rita Sklar, executive director of the American Civil Liberties Union of Arkansas, said she was disappointed with the Senate's override and said her group is considering suing.
"We are going to do everything within our power to protect the health and reproductive decision-making abilities of women and in this case that includes looking very carefully at litigation," she said.
Democrats who previously voted for the 20-week ban but against the override said they did so out of deference to Beebe and the concerns he raised over the measure's constitutionality.
"The budget's tight. We're working on giving businesses and individuals some tax relief. I don't think it makes sense to spend money on expensive litigation," said Sen. Larry Teague, D-Nashville, who is a co-chairman of the budget committee.
The 20-week near-ban is based on the disputed claim that a fetus can feel pain by then and therefore deserves protection from abortion. Those who support fetal pain bills say there is evidence that by 20 weeks, fetuses seek to evade stimuli in a way that indicates they are experiencing pain.
But the American College of Obstetricians and Gynecologists says it knows of no legitimate evidence that shows a fetus can experience pain. It says a fetus' brain begins its final stage of development between the 20th and 40th weeks of pregnancy, and that certain hormones that develop in the final trimester also must be present for it to feel pain. It's not known exactly when those hormones are formed.
According to the Guttmacher Institute, which tracks laws affecting women's health, seven other states have enacted similar fetal pain abortion laws. Similar laws in Georgia and Arizona have been blocked pending the outcome of legal challenges.
Mary Spaulding Balch, the director of state legislation for the anti-abortion group National Right to Life, applauded the Arkansas Legislature's vote overriding Beebe's veto.
"Basic compassion for human life demands that this legislation be enacted all over the country," Balch said.
Andrew DeMillo can be reached at www.twitter.com/ademillo