Although ultrasound devices already give us a very rough idea of the baby's measurements, it will not be until it is born that we can measure them "in person." When a baby is born it is the right time to weigh, carve and measure it (including the head circumference), and study the data adjusted in percentiles and by gestational age.
The most used classification is the adapted international, the calls Lubchenco curves (or Battaglia and Lubchenco curves, since both authors published the study in which they proposed their classification). On this scale, the newborn is classified according to its weight and gestational age.
The essay, published in 1967, is entitled “A practical classification of newborn infants by weight and gestational age” (”A practical classification of newborns by weight and gestational age“).
Babies can be defined in different ways according to their measurements and place in these curves, with distinction between preterm, term and postterm babies:
- Newborn preterm suitable for gestational age (RN PTAEG): Premature RN with weight, between 0th percentile and 90th percentile for gestational age.
- Newborn preterm small for gestational age (PTPEG RN): Premature RN weighing less than 0 percentile for gestational age.
- Newborn preterm large for gestational age (RG PTGEG): Premature RN weighing more than the 90th percentile for gestational age.
- Newborn at term suitable for gestational age (RN ATAEG): RN at term with weight between the 0th percentile and the 90th percentile for its gestational age.
- Newborn at small term for gestational age (RN ATPEG): Term RN weighing less than 0 percentile for gestational age.
- Newborn large term for gestational age (RN ATGEG): RN term with weight greater than the 90th percentile for gestational age.
- Newborn post term suitable for gestational age (RN PostTAEG): RN post term with weight between 0th percentile and 90th percentile for gestational age.
- Newborn post-term small for gestational age (RN PostPEG): Post-term RN weighing less than 0 percentile and gestational age.
- Newborn post-term large for gestational age (RN PostGEG): Post-term RN weighing more than the 90th percentile for gestational age.
This is the classification of the newborn according to the Lubchenco curves, from premature newborns to those born post-term, based on weight and said gestational age.
