Where are you getting the 3% figure from wars?
WW1, UK saw a 11-12% mortality rate among their troops. Germany saw an 18% mortality rate. The Russian empire ~ 14%
WW2 the USSR had a rate estimated at ~27%, UK 4%, US 3%, Germany ~27%, Australia 4%, Japan ~ 20%, Finland 3%
Spanish civil war, 10%
The US civil war saw a mortality rate of ~25% among enlisted men.
The napoleonic wars saw ~30% across the board.
And in the 1600s, you were expected to lose 10-30% of your sailors before even reaching your enemy due to disease and illness on the ship. Depending on the length of the voyage.
And as a final note. Death during childbirth is the highest for the first child. The risk will decrease for subsequent children. As in, a woman having her second child, is less at risk of dying from that childbirth than someone who ia birthing her first.
Not that it's a competition between the sexes.