Cohort study showed that growth rate increment has not been enough to prevent growth retardation of preterm infants and raised concerns about unbalanced growth.

AIM: We describe the postnatal weight gain, linear and head growth trends of surviving preterm infants from 2005 to 2017. METHODS: Multicentre cohort study, including surviving preterm infants <32 weeks (n = 21 084), from the Spanish Neonatal Network database, without major congenital malformations who were less than 50 weeks postmenstrual age at discharge. Outcomes were weight gain (g/kg/day), linear and head growth (cm/week) and changes in weight, length and head circumference z-scores from birth to discharge. The study period was divided into 2005-8, 2009-11, 2012-14 and 2015-17. RESULTS: Weight gain, linear growth and head growth were slightly higher in 2015-2017 than in 2005-2008: 12.2 ± 2.6 to 13.1 ± 2.5 g/kg/day, 0.98 ± 0.6 to 1.03 ± 0.6 cm/week and 0.76 ± 0.2 to 0.77 ± 0.3 cm/week, respectively. It was associated with a decreased fall in weigh, length and head circumference z-scores from birth to discharge (-1.32 ± 0.9 to -1.01 ± 0.84, -1.38 ± 1.2 to -1.18 ± 1.2 and -0.41 ± 1.2 to -0.33 ± 1.3, respectively). CONCLUSION: Postnatal growth restriction remained a common complication of prematurity despite some increment over the last years. Growth disproportionality seemed to be worsening as weight gain was increased more than linear growth.

The Effect of Morbidity and Sex on Postnatal Growth of Very Preterm Infants: A Multicenter Cohort Study.

BACKGROUND: Extrauterine growth restriction is common in the preterm infant, and it is associated with poor neurodevelopment. Nutrition plays an important role in postnatal growth, but growth is also influenced by other factors like co-morbidity, and, also, there might be sex differences. METHODS: This is a cohort study including preterm infants < 32 weeks at birth (n = 21,825) from the Spanish Neonatal Network database. The effect of sex and morbidity (patent ductus arteriosus, bronchopulmonary dysplasia, necrotizing enterocolitis and late-onset sepsis) on weight gain as well as linear and head growth from birth to discharge/death was assessed with linear regression models adjusted by gestational age and Z-scores at birth. RESULTS: The 4 selected morbidities had an independent effect on all 6 growth parameters studied, which was greater in the case of necrotizing enterocolitis: changes in weight, length and head Z-scores were -0.60 (95% CI: -0.66 to -0.55), -0.62 (95% CI: -0.70 to -0.54) and -0.63 (95% CI: -0.71 to -0.56), respectively. Weight gain and linear growth were overall more affected than head growth. Girls lost slightly more weight Z-scores (-0.03; 95% CI: -0.06 to -0.002) than boys after adjustment by morbidity. There were no significant gender differences regarding linear and head growth velocity (cm/week), although girls lost more head Z-scores (-0.14; 95% CI: -0.18 to -0.10). CONCLUSIONS: Main co-morbidities associated with prematurity have an impact on postnatal growth. Head growth is less affected than length and weight. Girls are at slightly higher risk of postnatal weight and head restriction after adjustment by morbidity.

The Impact of Postnatal Systemic Steroids on the Growth of Preterm Infants: A Multicenter Cohort Study.

Postnatal steroids, often used to prevent and treat bronchopulmonary dysplasia, may influence the growth of preterm infants, although data are scarce in the literature. This is a multicenter cohort study including surviving preterm infants <32 weeks at birth (n = 17,621) from the Spanish Neonatal Network SEN1500 database, without major congenital malformations. Linear regression models were adjusted for postnatal steroids, respiratory severity course (invasive mechanical ventilation at 28 days), progression to moderate-severe bronchopulmonary dysplasia (O2 at 36 weeks), length of stay, sex, gestational age and z-scores at birth. A subgroup analysis depending on the timing of administration, ventilation status at 28 days and moderate-severe BPD diagnosis was also performed. Overall, systemic postnatal steroids were not independently associated with poorer weight gain (0.1; 95% CI: -0.05 to 0.2 g/kg/day), linear growth (0; 95% CI: -0.03 to 0.01 cm/week) or head circumference growth (-0.01; 95% CI: -0.02 to 0 cm/week). Patients who received steroids after 28 days or who were not O2 dependent at 36 weeks after having received steroids gained more weight (0.22; 95% CI: 0.04 to 0.4 and 0.2; 95% CI: 0.004 to 0.5 g/kg/day, respectively). Globally, systemic postnatal steroids had no significant adjusted effect on postnatal growth.