Aim To investigate the growth outcomes of infants with slow weight gain (weight faltering) in the first 9 months of life.
Methods Weight gain (conditional on initial weight) from birth to 8 weeks, and 8 weeks to 9 months was measured on term infants from the Avon Longitudinal Study of Parents and Children. Cases of slow weight gain were defined as those infants with a conditional weight gain below the fifth centile, and these were compared with the rest of the cohort as controls. Children were subsequently measured at 2, 4, 7, 10 and 13 years and compared to the UK 1990 reference.
Results Weight data were available on 11 499 infants: 507 with ‘early’ slow weight gain before 8 weeks and 480 with ‘late’ slow weight gain between 8 weeks and 9 months.
The early group showed enhanced weight gain (catch-up) from 8 weeks until 2 years, then grew as expected. At 13 years their mean body mass index (BMI) SDS (99% CI) was 0.21 (0.02 to 0.40), controls 0.33 (0.29 to 0.38).
The late group showed slow weight gain throughout childhood, with enhanced weight gain between 7 and 10 years; however they remained lighter and shorter than the reference and controls up to the age of 13 years. The mean BMI sds (99% CI) at 13 years was −0.13 (−0.33 to 0.07), controls 0.35 (0.31 to 0.39). The figure 1 illustrates the weight sds of the two groups up to age 13.
Conclusions Children showing early slow weight gain in infancy catch up in weight by 2 years. Infants with late slow weight gain catch up slowly in weight through childhood but remain lighter and shorter than their peers at 13 years. These results will help clinicians in advising parents of the long term outcomes of weight faltering in infancy.