Neonatal deaths in the 2000–2011 period were
evenly distributed between early deaths (within
the first 12 hours of life) and those occurring
between 12 hours and 28 days of age (Table 2).
In post hoc subgroup analyses, we did not detect
significant heterogeneity in the change in overall
mortality among the three periods between
centers with continuous participation in the Neonatal
Research Network and centers with noncontinuous
participation (Table S3 in the Supplementary
Appendix). Overall, continuous participating
centers provided comfort care more frequently in
the delivery room (P