The airlines is saying that they're conducting a "thorough and systematic review" for pets that travel in cargo. The most tragic involved a pet travelling in the passenger cabin that died after being placed in an overhead bin on a Houston-New York flight on 12 March.
United did not give a date when it would resume the PetSafe transport program, but the carrier said it expects to complete its review by May 1.
Among other issues under examination in PetSafe, United will consider which pets to accept, said Mr Charlie Hobart, a spokesman for the Chicago-based airline. Additionally, it's partnering with independent experts in travel safety for pets.
Since the PetSafe service is for animals in the freight compartment, different procedures for the programme wouldn't have helped protect the bulldog, which died in the passenger cabin.
In 2017, United apologized for the death of a dog put in the cargo hold of a plane held for hours on a tarmac last summer.
United carried about 42 percent more animals in the cargo hold in 2017 than in 2015, and it accounted for about 27 percent of all animals U.S. airlines transported a year ago, according to the U.S. Department of Transportation.
Last week was an extraordinary bad week for pets flying on United.
United Airlines is pausing its pet-shipping business after mishaps that include the airline mistakenly sending a Kansas-bound dog to Japan. In 2017, airlines reported 24 deaths, 15 injuries and one loss in almost 507,000 animals transported, according to Department of Transportation data.