In nature it is not as stressful as it is in captivity. In nature, seasonal changes trigger the breeding season gradually. When we breed tree frogs in captivity, we "cycle" them in a brief period of time (compared to nature), which includes allowing their tank to dry out, and with holding food until they get fed like pigs right before going into the rain chamber. It can be very stressful on them.
Remember, even in this day and age, even human childbirth is a life threatening condition. Believe it or not.
Education is the most powerful weapon we can use to change the world ~ Nelson Mandela