מדרש על שבת 2:6

R. Yosé the son of Hanina declared: We have learned that women die in childbirth because of three transgressions they commit. But why in childbirth? Because Satan always brings charges against a person in a time of danger.²Highway travel and pregnancy were both considered dangerous, and Satan brings charges against a person when he endangers his life. See Tan. Noah 1, M. Shabbat 2:6.