Sainsbury supply the morning-after pill through five of its stores, in line with government guidelines, in areas where teenage pregnancy is a particular problem.
Earlier in the year the pro-life groups waged a campaign against Tesco which subsequently pulled out of the trial.
“We are organising a full-scale campaign as we did on Tesco,” national director of the Society for the Protection of Unborn Children told the Catholic Herald newspaper. “We feel confident that Sainsbury’s will feel the weight of customer dissatisfaction, as Tesco did,” he said.
Customers were said to be concerned that the drugs were being given to children without their parents' consent.