Having a child under a certain age has all the health risks of a serious disease putting the life of the mother and child at much higher risks. Why shouldn't it be treated as such?
A 5% chance of your child dying when you give birth at age 15 and lower seems pretty reasonable to me? At least I’d have expected those number to be far higher.
At 16-17 it’s 4% and at 18-19 it’s 3%, which makes it even better, but 19 out of every 20 children surviving longer than 28 days is pretty good.
If you are old enough to have a child, you are very likely old enough to successfully raise one. Otherwise the human race wouldn’t exist.