Leisure time physical activity before and during mid-pregnancy and offspring adiposity in mid-childhood

Effects of maternal leisure time physical activity (LTPA) on paediatric obesity are unknown. The objective of this study was to examine associations of maternal LTPA with offspring overall and central adiposity in mid-childhood.

We analysed data from 802 mother-child dyads from Project Viva, a prospective pre-birth cohort study. Women reported average weekly LTPA before and during mid-pregnancy. At age 7-10 years, we measured fat, truncal fat and lean mass with dual-energy X-ray absorptiometry. Using multivariable linear regression, we examined associations of maternal LTPA with offspring adiposity, adjusting for child age and sex, maternal race/ethnicity, education, age, pre-pregnancy body mass index, marital status and smoking status.

Mean (standard deviation) of LTPA before and during mid-pregnancy were 9.5 (8.1) and 7.1 (7.0) h week(-1) . At mean age 7.8 (0.8) years, childhood fat, truncal fat and lean mass indices were 4.3 (1.8), 1.4 (0.8) and 12.9 (1.4) kg m(-2) . We did not find that higher maternal LTPA was associated with lower child adiposity outcomes. For example, compared with 0-3 h week(-1) of LTPA during mid-pregnancy, children of mothers with +8 h week(-1) had fat mass index 0.07 kg m(-2) (95% confidence interval: -0.22, 0.36). In analyses of within-person LTPA change from before to mid-pregnancy, compared with +2 h week(-1) decrease in LTPA, increased LTPA (2 ± h week(-1) ) was associated with a 0.09 kg m(-2) fat mass index (-0.25, 0.43).

Contrary to our hypothesis, higher LTPA before and during mid-pregnancy, and the change between them, were not associated with lower adiposity in mid-childhood.