Maternal Physical Activity and Child Body Size at 8-10 Years

Abstract

Leisure time physical activity (LTPA) during pregnancy is related to slight decreases in birth weight within the normal range. However, the effect of LTPA during pregnancy on offspring body size in childhood is not known. PURPOSE: To evaluate the relationship between trimester specific maternal LTPA and body mass index (BMI), percent fatness (%fat), and waist circumference (WC) during childhood. METHODS: Mother/child (n = 20 pairs) height, weight, and %fat (BodPod) were assessed. WC was measured in children only, and BMI was calculated for both mother and child. Current maternal and child aerobic fitness (VO2max) were assessed with a graded exercise treadmill test. Current maternal LTPA and recalled pre-pregnancy and trimester-specific LTPA were assessed for a typical week via a Modified Activity Questionnaire (MET·min/week). Spearman correlations were used to assess relationships among variables. RESULTS: Mean (± SD) age, %fat, and VO2max for mothers was 41.1 ± 4.4 yrs, 32.6 ± 8.0 %, and 37.5 ± 12.5 ml/kg/min, respectively, and for children: 9.2 ± 0.7 yrs, 26.7 ± 6.5 %, and 46.5 ± 8.8 ml/kg/min, respectively. LTPA decreased during pregnancy: 1269 ± 1153, 1010 ± 984, and 795 ± 961 MET·min/week for the 1st, 2nd, and 3rd trimesters, respectively. Maternal LTPA in the month before pregnancy was inversely related to child %fat (r = -0.60, p = 0.005). First trimester LTPA was not associated with any measure of child size. Second trimester LTPA was inversely correlated with child WC (r = -0.45, p = 0.048), while third trimester LTPA showed a trend for significance (r = -0.43, p = 0.056). Average PA across all three trimesters was not significantly related to any child body size variables (p > 0.05). Current maternal fitness was inversely correlated with child BMI (r = -0.46), %fat (r = -0.55), and WC (-0.56), all p < 0.05, while child fitness was only correlated with %fat (r = -0.68, p = 0.001). CONCLUSIONS: Maternal LTPA in mid-to-late pregnancy may be associated with child WC at 8-10 years of age and children of fit women appear to have more favorable body size measurements. These preliminary findings provide support for LTPA during pregnancy to have a beneficial effect on child body size.