450 - Maternal Metabolic Health and Perinatal Factors Influencing Preterm Infant Body Composition at Hospital Discharge

Poster Number: 450
Publication Number: 450.335

Lindsay Ellsworth, University of Michigan Medical School, Ann Arbor, MI, United States; Subramaniam Pennathur, University of Michigan Medical School, Ann Arbor, MI, United States

Background: Preterm infants are at risk for long-term metabolic disease. Evaluating growth patterns including body composition measures are key to accurately assess nutritional status, quality of growth and to identify modifiable perinatal factors.

Objective: To characterize the relationship between maternal metabolic factors (overweight/obesity (OW/OB), gestational weight gain (GWG)), infant nutrition, and infant growth with preterm infant body composition.

Design/Methods: A prospective, observational mother-infant cohort of infants born ≤34 weeks gestational age (GA) or ≤1800 grams birth weight. Infants were excluded if fed exclusively formula or diagnosed with congenital anomalies or a genetic syndrome. Maternal data included pre-pregnancy body mass index (BMI), GWG, and calculated GWG Z-score. Infant weight and length were collected longitudinally from birth to hospital discharge with Z-scores calculated according to Fenton growth curves. At discharge or 40 weeks, infant body composition was measured using air displacement plethysmography (PeaPod, Cosmed) to evaluate fat free mass, fat mass, and percent body fat for which Z-scores were calculated. Analyses were conducted with Pearson correlations to evaluate associations between maternal and perinatal factors with infant body composition.

Results: For this pilot study, 19 infants (17 mothers, 2 sets of twins) able to complete PeaPod measurements were included in analysis. Infant GA ranged from 26 to 34 weeks with 47% female. Infants received on average 81% mother’s own milk over their hospitalization. 47% of mothers had an OW/OB pre-pregnancy BMI. Infant body composition showed mean fat free mass (FFM) 2.02 kg (±0.36 kg) and body fat percentage 12.76% (±3.90%). FFM Z-score was less than the 10th percentile for 31% of infants. Maternal GWG Z-score was negatively correlated with infant FFM Z-score (r=-0.50, p=0.03) and discharge weight Z-score (r=-0.54, p=0.02); however maternal BMI showed no correlation with infant FFM. Infant FFM Z-score was positively correlated with birth weight Z-score (r=0.78, p= < 0.0001) and discharge weight Z-score (r=0.95, p < 0.0001). There were no correlations with percentage of mother’s milk intake versus donor milk or estimated early protein, caloric intake. There were no correlations with infant body fat percentage.Conclusion(s): Preterm infants are at risk for growth failure with suboptimal fat free mass accretion at the time of discharge. Maternal health status may impact body composition with negative correlations between GWG and infant FFM. Infant body composition provides a more complete assessment of adiposity development.
Figure 1. Preterm infant discharge fat free mass (FFM) Z-score across gestational age at birthThe red dotted line represents the 10th percentile of FFM Z-score.