It’s because of the G.O.P.

Marmora - It’s because of the G.O.P. that the United States is one of only a few countries in the world without guaranteed paid maternity leave. Republicans fought universal health care and resisted the expansion of Medicaid; that’s one reason a child in the United States is three times as likely to die by the age of 5 as a child in, say, Slovenia or Estonia.
Think of it this way: We’d be saving the life of one American child between the ages of 1 and 5 every three hours if we had the same child mortality level as Norway or Finland.