Table 1.

Definitions of birth weight categories and preterm birth

Category	Definition
Birth weight categories
Normal birth weight	>2,500 and <4,000 g (usually)
Large for gestational age	>2 SD above the mean birth weight for gestational age
Low birth weight	<2,500 g
Very low birth weight	<1,500 g
Appropriate for gestational age	±2 SD of the mean birth weight for gestational age
Small for gestational age	>2 SD below the mean birth weight for gestational age
Intrauterine growth restriction	Evidence of fetal malnutrition and growth restriction at any time during gestation
Gestational categories
Extremely preterm	<28 weeks’ gestation
Very preterm	<32 and >28 weeks’ gestation
Moderately preterm	<34 and >32 weeks’ gestation
Late preterm	<37 and >34 weeks’ gestation
Full term	>37 weeks’ gestation

Term fetal macrosomia implies fetal growth beyond a specific weight, usually 4.0 or 4.5 kg, regardless of fetal gestational age [18, 19]. In this document, we use the term “growth restriction” to refer to both SGA and IUGR [reprinted with permission from 20].