Something else that I would point out in these comparisons...

There is some evidence that women who seek care with homebirth midwives are significantly less likely to give birth preterm than those who seek care with obstetricians--possibly as much as 3 times higher in women seeking care with obstetricians.  Since preterm birth is a leading cause of neonatal death, I'd argue that the most accurate comparison of homebirth neonatal mortality compared to hospital neonatal mortality would require that a matched group of women intending hospital birth at the start of the pregnancy and women intending homebirth at the start of the pregnancy be followed to look at neonatal death rate in each group as a total, regardless of prematurity.

Also, the "low risk" hospital birth group excludes twins in a defacto manner because the vast majority of all hospital birthed twins are born prior to 37 weeks because if they don't come before then on their own (labor starting or some indication arrising for induction/cesarean), then Dr.'s routinely induce twins at 37 weeks for no other reason than twin status.