Association Between Weight for Length and the Severity of Respiratory Morbidity in Preterm Infants.
Objective: To determine whether higher weight-to-length z-scores after 32 weeks of gestation are associated with higher pulmonary scores (PSs) in preterm infants requiring respiratory support using a prospective observational study.
Methods: Infants born at <30 weeks, with a post-menstrual age (PMA) of 30-33 weeks, were enrolled. The infant's weight, length, and head circumference were measured weekly. Data on calories/kg/d, protein g/kg/d, weight-for-length percentiles, z-scores, and BMI at 33 through 40 weeks PMA were collected. The PS was calculated.
Results: We analyzed 91 infants. The mean gestational age was 26.9 ± 1.7 weeks. The mean birthweight was 0.898 ± 0.238 kgs. They were predominantly African American (81.3%) and girls (56%). Postnatal steroids were administered in 26.4% of the infants. The mean duration of invasive ventilation was 19.23 days ± 28.30 days. There was a significant association between the PS and W/L z-score (p < 0.0001). For every one-unit increase in W/L z-score, the PS increased by 0.063. There was a significant association between the PS and W/L percentile (p = 0.0017), as well as BMI (p ≤ 0.0001). For every unit increase in W/L percentile, the PS increased by 0.002, and for a unit increase in BMI, the PS increased by 0.04. The association remained significant after postnatal steroid use, sex, and corrected and birth gestational ages were included in the regression analysis. Nutrition did not affect the anthropometric measurements.
Conclusions: Our study is the first to demonstrate that a higher BMI and W/L may adversely affect the respiratory severity in preterm infants. Studies with larger sample sizes are needed to confirm our findings.
Keywords: BMI; BPD; length; preterm; weight.