Neonatal

adj. pertaining to newborn babies

In basic English usage, an infant is defined as a human child at the youngest stage of life, specifically before they can walk and generally before the age of one (see also child and adolescent).The term "infant" derives from the Latin word in-fans, meaning "unable to speak." There is no exact definition for infancy. "Infant" is also a legal term with the meaning of minor; that is, any child under the age of legal adulthood.A human infant less than a month old is a newborn infant or a neonate. The term "newborn" includes premature infants, postmature infants and full term newborns.
See more at Wikipedia.org...

Neonatal /neo·na·tal/ pertaining to the first four weeks after birth. ne·o·na·tal adj. Of or relating to the first 28 days of an infant's life. [more]Neonatal - Community and Resources

Adjective
1. relating to or affecting the infant during the first month after birth; "neonatal care"; "the neonatal period"
(pertainym) neonate, newborn, newborn infant, newborn baby

adj. neonatal, pertaining to newborn babies