Postnatal Growth at 64 Weeks Postmenstrual Age in Preterm Infants Delivered at ≤ 34 Weeks’ Gestation: A Single Center Study

Objective To study the postnatal growth at 64 weeks postmenstrual age (PMA) in preterm neonates born at ≤ 34 weeks gestational age. Methods A cross-sectional study was conducted between August, 2019 and November, 2021, wherein, we took anthropometric measurements of neonates (delivered at ≤ 34 weeks’ gestation) at 64 (± 2) weeks PMA. The rapidity of postnatal growth was categorized according to change in the z -score of anthropometric measures, viz, weight-for-age, length-for-age and head circumference-for-age, between birth and 64 weeks PMA. For each of the growth parameters, growth rate was categorized according to the change in z -score ( z -score at 64 weeks PMA minus z -score at birth) as slow (< −0.67), acceptable (−0.67 to < 0.67), and rapid (≥ 0.67). Results Out of the 156 preterm neonates evaluated, weight gain was slow, acceptable and rapid in 95 (60.8%), 45 (28.9%), and 16 (10.3%), respectively. Length gain was slow, acceptable, and rapid in 87 (55.7%), 49 (31.4%), and 20 (12.9%) infants, respectively. Head circumference gain was slow, acceptable and rapid in 103 (66.5%), 42 (26.5%), and 11 (7.0%) infants, respectively. The risk [aOR (95% CI)] for slow weight gain increased with early initiation of complementary feeding [8.0 (3.5, 18.0)] and decreased with a longer duration of EBF [0.4 (0.2, 0.6), P < 0.001]. The risk for rapid weight gain also decreased with the longer duration of EBF [0.27 (0.1, 0.5), P < 0.001]. Gestational age < 32 weeks, weight for gestation at birth, and re-hospitalization following discharge were the other key factors influencing the growth rate Conclusion Among babies born preterm (≤ 34 weeks), more than half had slow gain in weight, length and head circumference. EBF till 6 months corrected age was protective against slow and rapid weight gain.