New Australian birthweight centiles

Area of Science:

• Obstetrics and Gynecology
• Neonatal Health
• Biostatistics

Background:

• Accurate birthweight centile charts are crucial for identifying fetal growth abnormalities.
• Previous Australian charts may underestimate intrauterine growth restriction due to the exclusion of intervention-initiated births.

Purpose of the Study:

• To develop updated, population-based Australian birthweight centile charts.
• To improve the accuracy of identifying small for gestational age (SGA) babies.
• To incorporate recent Australian perinatal data and exclude pre-term deliveries by obstetric intervention.

Main Methods:

• Retrospective observational study using Australian Institute of Health and Welfare National Perinatal Data Collection (2004-2013).
• Included singleton births (23-42 weeks gestation) with spontaneous onset of labour.
• Excluded births initiated by obstetric intervention to minimize bias.

Main Results:

• Utilized data from 2,807,051 singleton live births, with 1,582,137 (56.4%) having spontaneous labour onset.
• The 10th centile for pre-term births was higher in the new charts compared to previous Australian charts.
• The updated charts reflect more recent population data and exclude intervention-influenced births.

Conclusions:

• Existing birthweight charts may underestimate intrauterine growth restriction.
• Excluding intervention-initiated births and using recent data creates more accurate centile curves.
• These updated Australian birthweight charts can enhance the diagnosis of SGA babies.