Prepregnancy Physical Activity in relation to Offspring Birth Weight: A Prospective Population-Based Study in Norway—The HUNT Study

Table 2

Maternal pre-pregnancy leisure time physical exercise and mean offspring birth weight from linear regression analyses.

Physical exercise	No. of persons	Mean; birth weight (g)	Crude difference	Adjusted^a difference (95% CI)	P trend^b
Sessions per week
None	147	3589.0	−25.2	−26.9 (−137.9 to 84.2)
<1	647	3632.5	18.3	21.7 (−64.8 to 108.3)
1	591	3639.7	25.5	31.0 (−56.1 to 118.1)
2-3	491	3590.4	−23.7	−24.4 (−113.2 to 64.4)
≥4	150	3614.1	0.0	0.0 (reference)	0.49
Total exercise^c
No activity	147	3589.0	−38.9	−53.0 (−141.8 to 35.8)
Low	647	3632.5	4.6	−3.5 (−58.3 to 51.4)
Medium	641	3606.9	−21.0	−36.9 (−91.5 to 17.8)
High	591	3627.9	0.0	0.0 (reference)	0.56

CI: confidence interval.
^aAdjusted for maternal age (20–24, 25–29, 30–34, and 35–39 years), smoking (never, former, current, and unknown), and parity (primiparous, 1-2 children, and 3–6 children).
^bP value from trend test when categories were entered as an ordinal variable in the regression model.
^cBased on a summary score of frequency, duration, and intensity of exercise.