The initial period following birth, characterized by significant physiological adjustment to life outside the womb, concludes after a defined duration. This period typically lasts for approximately the first two to three months of an infant’s life. For instance, reflexes like the Moro reflex, which are prominent immediately after birth, gradually diminish as this phase nears its end.
Recognizing the end of this phase is crucial for understanding an infant’s developmental trajectory. It allows caregivers and healthcare providers to anticipate and support subsequent milestones in motor skills, cognitive abilities, and social-emotional development. Historically, understanding the distinct features of this early period has informed pediatric care and developmental assessments.