Perinatal & Pediatric
Association of maternal physical activity domains, intensities and duration with neonatal anthropometry in the NICHD Fetal Growth Studies – Singletons Kathryn Wagner* Kathryn Wagner Wagner Wagner Wagner Wagner Wagner Wagner Wagner Wagner Wagner Wagner Wagner Wagner Massachusetts College of Pharmacy and Health Sciences
Prior studies have focused on total or exercise physical activity (PA) and birthweight (BW), potentially missing nuanced relationships between PA domains, intensities and duration with neonatal size, including fat measures.
In a prospective cohort (n=2441), self-reported first trimester PA (type, intensity and duration) were categorized as tertiles and whether they met ACOG guidelines. Neonatal anthropometrics (BW, g; birth length (BL, cm); circumferences (cm) – head (HC), mid-upper arm (MUAC), chest (CC), abdominal (AC), and mid-upper thigh (MUTC); and skinfold thicknesses (mm) –tricep (TSF), subscapular (SSF), abdominal (ASF), and anterior thigh (ATSF)) were measured after delivery or abstracted from medical records. Generalized linear regressions evaluated the associations, adjusted for covariates.
Home, work, light, moderate, and duration of PA and meeting ACOG guidelines were associated with smaller neonatal anthropometrics. Specifically, 3rd tertile home PA was associated with smaller MUAC (β=-0.15;SE=0.08), TSF (β=-0.19;SE=0.09), CC (β=-0.24;SE=0.12), ASF (β=-0.18;SE=0.09) and ATSF (β=-0.24;SE=0.12), compared to the 1st tertile. 2nd tertile work PA, but not 3rd, was associated with smaller BW (β=-89.6;SE=29.7). 2nd and/or 3rd tertile light PA was associated with smaller TSF (2nd: β=-0.17, SE=0.08; 3rd: β=-0.19;SE=0.08) and CC (3rd: β=-0.24;SE=0.11). 2nd tertile moderate PA was associated with several smaller measures (BW: β=-71.4,SE=26.8; HC: β=-0.19,SE=0.08; MUAC: β=-0.15,SE=0.07; CC: β=-0.22,SE=0.11; AC: β=-0.30,SE=0.011; ASF: β=-0.19,SE=0.08). 3rd tertile PA duration was associated with a smaller SSF (β=-0.16,SE=0.08). Meeting ACOG guidelines was associated with smaller BL (β=-0.21;SE=0.11), compared to not. Transportation, exercise, sedentary and vigorous PA were not associated with neonatal measures.
These findings highlight non-monotonic relationships of PA and neonatal anthropometry, as well as the importance of assessing PA domains beyond exercise.