A Walmart spokeswoman said stores in most states have a five-per-day limit on baby formula at the request of the Food and Drug Administration. CVS said it recently began limiting purchases in stores and online to three per consumer. Walgreens said it implemented limits in stores and online last month. Target declined to comment, and Kroger didn’t respond to requests for comment.

Parents say that baby formula has been hard to find for months in parts of the country. Supplies were further strained by a February recall by Abbott Laboratories, one of the biggest manufacturers, after consumer complaints of bacteria contamination that could cause severe illness in infants.

Four infants who consumed its products were hospitalized and one died. The company expanded the recall, which involved powdered versions of its Similac, Alimentum and EleCare brands made at the same Michigan facility, on March 1 after being informed of the death of another infant that consumed its product.