If you're going to get super utilitarian about it, strict years of life lost is not the best measure. As nearly all of human history proved out, very young children, especially infants, are particularly easy to replace. It's losing people in the prime years that really hurts a society, why for instance the US Civil War and the two World Wars were so terrible, where huge regions lost a majority of 20-40 year old men. Although again, if we're being very utilitarian, men are a lot less valuable than women, which is at least one reason we've usually sent men to war. Childbearing doesn't scale nearly as easily as child seeding.