Trends in long term growth outcome: comparison of two birth cohorts (year 2007-08 and year 2015-16).

Very low birth weight (VLBW) infants comprise between 4% and 8% of live-births and about one-third of deaths during the neonatal period. The objective of the study is to evaluate and compare the long-term growth outcomes of VLBW infants among two different birth cohorts: Cohort 2007-08 (cohort 1) and cohort 2015-16 (cohort 2), in a cross-sectional observational study. The neonatal and perinatal data of cohort 1 was collected from available trial data and the same data from cohort 2 was collected from patient case files and patient history. The primary outcome of the study was to compare the growth outcomes of VLBW infants attending the follow-up clinic between 12 and 18 months of corrected age from two different birth cohorts. Respectively, 238 and 268 infants were eligible for inclusion in cohort 1 and 2. Among the eligible infants, 148 infants in cohort 1 and 178 infants in cohort 2 were available for primary outcome assessment during the recruitment phase. The weight and length at corrected age (12 to 18 months) is significantly higher in cohort 2 compared to that in cohorts 1 although the mean age at assessment is similar between the two groups. There is a significant reduction in the incidence of underweight in infants that belonged to cohort 2. The proportions of infants who are underweight at follow-up were significantly lower in cohort 2 when compared to cohort 1, and there were no significant differences in the incidence of stunting and microcephaly among both the cohorts.