Nairobi — Rescuers found four survivors Thursday in the rubble of an apartment building that collapsed six days ago amid heavy rains in the Kenyan capital, raising hopes that more people might still be alive in a disaster that has left dozens dead and missing.The first to be rescued was a pregnant woman, although her husband said that amid the joy of finding her alive, doctors also reported that their baby had not survived. In addition, one of those found alive later died en route to the hospital, officials said.Soldiers, firefighters and volunteers have been working around the clock since the April 29 collapse of the seven-story building in a desperate search effort, and their spirits were lifted Tuesday when a nearly 6-month-old girl — dehydrated but relatively unscathed — was found in a wash basin.Then on Thursday, they found 24-year-old Elizabeth Night Odhiambo, who was eight months pregnant, said her husband, Stephen Onyango.A crowd broke into applause as Odhiambo — under a blanket and with her face covered with an oxygen mask — was carried to an ambulance in a scene broadcast live on Kenyan TV.Odhiambo was taken to Kenyatta National Hospital, where she underwent an emergency cesarean section, but doctors told Onyango the baby had not survived."A doctor pulled me aside and told me, 'Your wife is here in the (operating) theater, and when she was in the collapsed building, the baby died in her stomach and we have removed it,'" Onyango told The Associated Press. "He showed me the baby, and I told him it was OK."Despite that news, Onyango said he was joyful his wife was still alive."I cannot say the happiness I have," the truck driver said in a telephone interview. "I have never had such happiness like this in my life."Onyango said he was able to comfort his wife after the surgery.Pius Masai, the head of the Disaster Management Unit, said that of the other three people rescued after Odhiambo, one died because the ambulance did not have advanced life-saving equipment. The condition of the other two was not immediately known.The disaster has killed 37 people and injured 134. About 70 people remain missing, said Kenya Red Cross head Abbas Gullet, and rescuers were working around the clock to find survivors.Before military engineers broke through slabs of concrete that had trapped Odhiambo in a corner of the building, medics had managed to give her oxygen and an intravenous drip of water and glucose, according to Kenya's Disaster Management Unit.Authorities initially used backhoes in the search, with firefighters and volunteers also removing chunks of debris by hand in the frantic rescue effort. A day after the collapse, the military brought in special equipment. President Uhuru Kenyatta visited the scene.Trained dogs were brought in, along with special equipment to detect breathing and movement, said military spokesman Col. David Obonyo.Authorities say it is rare for anyone to survive more than 72 hours without water in such instances.Following the 2013 collapse of the eight-story Rana Plaza factory in Bangladesh, a 19-year-old woman was rescued after being trapped in the rubble for 17 days, surviving on four packets of cookies and some water. It was the worst garment-industry disaster in history, killing 1,127 people.In Haiti's 2010 earthquake, a 17-year-old girl was found severely dehydrated and near death in a collapsed home 15 days after the quake struck. Rescuers said she may have had access to water from a bathroom.The Nairobi collapse occurred in the low-income Huruma neighborhood, and it came amid Kenya's April-May rainy season.The building was constructed less than 5 meters (15 feet) from a river, when it should have been at least 30 meters away, said local lawmaker Steven Kariuki. The National Construction Authority said it had marked the building as unfit for habitation, but the county government failed to follow up.A neighbor said the building had been constructed rapidly and poorly, and its more than 125 single rooms were snapped up quickly at a rent of $35 per month.Onyango said his wife, 2-year-old son and a niece were having dinner in their apartment on April 29 when he heard neighbors yelling to each other that "the building has a crack on the ground floor," and he went to check on it.As he was descending the stairs, Onyango said he changed his mind and went back to his apartment to evacuate his family, telling his niece to take his son outside.He looked back and saw his wife following him down the stairs when "suddenly there was a loud noise and stone slabs and concrete started falling," he said."I jumped into the balcony, and it collapsed with me to the ground," he said.After handing a neighbor's injured child over to rescuers amid the dust and debris, Onyango said he tried to get to his wife, but found the staircase blocked.Dizzy and struggling to breathe, he said he was put in a Land Rover to be taken to the hospital. After it started its journey, the vehicle stopped twice — once to pick up an injured 3-month-old and then again to pick up another child, who Onyango realized was his 2-year-old son, who was only slightly hurt.At the hospital, he was later contacted by his niece to say she was safe.The two owners of the building were taken into custody but released on $5,000 bail Wednesday, pending formal charges.Most of Nairobi's 4 million people live in low-income areas or slums. Housing is in high demand, and unscrupulous developers often bypass regulations.After eight buildings collapsed and killed 15 people in the country last year, Kenyatta ordered an audit of all the country's buildings to see if they are up to code. The National Construction Authority found that 58 percent of buildings in Nairobi are unfit for habitation.