Doctors opted for an emergency cesarean section at 24 weeks' gestation after discovering the fetus wasn't gaining weight. The baby boy weighed 9.45 ounces at his August birth—and has survived, making him the smallest baby boy ever to do so. The BBC reports the baby was discharged from Tokyo's Keio University Hospital Feb. 20, two months after his due date, after reaching 7 pounds. "I am grateful that he has grown this big because, honestly, I wasn't sure he could survive," the boy's mother tells Reuters. The BBC describes him as small enough to be held in a pair of cupped hands (see photos here).
Reuters reports the University of Iowa maintains a Tiniest Babies registry that lists the previous record-holder: a German boy born in 2009 who weighed 9.67 ounces. The tiniest child to survive remains a German girl born in 2015 who weighed 8.89 ounces. Girls born extremely small have a higher survival rate than boys, possibly because their lungs develop faster: Indeed, the Japan Times notes the registry lists just 23 babies who weighed less than 10.58 ounces at birth and survived; 19 of them were girls. The Japanese child doesn't seem to have been added to the list yet. (Why being born unable to breathe isn't a death sentence anymore.)