A nurse and a baby died in the blast and a second infant died Thursday night, Mexico City authorities said. At least 70 people were injured.
About 75 percent of the hospital collapsed, officials said. By late in the day, rescuers determined no one was left trapped in the rubble.
Mayor Miguel Angel Man-cera said some of the injured were about to be released from area hospitals, including some mothers who suffered injuries while using their bodies to shield their children.
A 25-year-old nurse and a newborn between 2 and 3 weeks old died at the scene and a second baby died several hours later at another hospital, said Armando Ahued, the citys health secretary. He said 21 babies were injured, and nine of those and seven adults were in serious condition.