GESTATION AND BIRTH WEIGHT DISORDERS

Low birth weight (LBW) refers to the babies weighing with lt; 2500 gm at birth, while those lt;1500 gm and lt;1000 gm at birth are termed very low birth weight (VLBW) and extremely low birth weight (ELBW).

Based on the intrauterine growth and position on the intrauterine growth charts (Fig. 12.10), all babies at birth may be classified, irrespective of the gestation, as:

• Appropriate for date (AFD), i.e. birth weight within the normal limits (10^th-90^th percentile) for gestation

• Smallfor dates (SFD), i.e. birth weight less than normal (lt;10^th percentile) for gestation

• Largefor date (LFD), i.e. birth weight more than normal (gt;90^th percentile) for the gestation.

However in practice, LBW, irrespective of the gestation, has been identified as the most important markers of adverse perinatal and neonatal outcome in India, with reported rate of ~18% as per recent NFHS- 5,2021. Since gestational age is main determinant of birth weight, the term LBW encompass both - preterm LBW and term LBW, discussed in following sections.

12.11.1