Summary
The aim of the study was to estimate the associations between physiological neonatal weight loss and body mass index at the end of growth.
Materials and methods. The study was retrospective longitudinal. Personal health records were analysed. Data were collected in 2009-2010 and 2012 at three branches of "Centro" outpatient clinic of Vilnius city. Personal health records of 243 children were included in the study. Selection criteria: healthy and breastfed full term infants born in 1990. The data recorded from the personal health records included birth weight, infant's weight leaving the maternity unit (neonatal weight loss in percent was calcul ated using those two indices) and main body size indices up to the age of seventeen years. Personal health records of 156 children (83 boys and 73 girls) who left the maternity unit on 3rd, 4th and 5th day after birth were included in the final analysis. Body mass indices were transformed to Z-scores.
Results. No statistically significant differences were established between neonatal weight loss (%) in boys and girls (p>0.05), therefore children were not divided into groups according to their sex while conducting further analysis. Neonatal weight loss (%) of children who left the maternity unit on 3rd day was 3.2±1.6%, on 4th day 3.5±3.5%, and on 5th day 2.7±1.7%. Correlations between neonatal weight loss and body mass index at the end of growth were low and statistically not significant.
Conclusions. The results of the study did not confirm the primary hypothesis about the associations between neonatal weight loss and body mass index at the end of growth. However, it is plausible that those results may be explained by the small number of personal health records included in the study and, furthermore, the fact that the exact day of the peak neonatal weight loss was unknown. In the authors' opinion, a prospective longitudinal study is needed to confirm or finally reject the primary hypothesis.
Keywords: neonatal weight loss, body mass index, personal health record, longitudinal study.
