Small Beginnings, Complex Outcomes: Understanding Birth Size and Health Consequences

Abstract

The neonatal period is a critical phase characterized by rapid growth and development, yet it is also a time of heightened vulnerability. Neonatal mortality, defined as death within the first 28 days of life, remains a pressing public health concern globally, with an estimated 2.3 million neonatal deaths occurring annually [1]. In India, despite notable improvements in maternal and child health in recent years, neonatal mortality rates remain high at 25/1000 live births, accounting for more than half of under-five deaths [2]. The intrauterine course and the point of transition to extrauterine life are the most critical determinants of immediate neonatal course as well as long term health. Within this context, birth size and gestational age play the most pivotal roles in shaping the trajectory of neonatal health outcomes. Low birth weight (LBW), typically defined as weighing less than 2500 grams at birth, and preterm birth, occurring before 37 weeks of gestation, are two key statistical thresholds.