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

Table 3

Odds ratio (OR) from logistic regression for giving birth to a marcosomic infant (i.e., birth weight > 4000 g) in association with maternal pre-pregnancy leisure time physical exercise.

Physical exercise	No. of; persons	No. of cases	Crude; OR	Adjusted^a OR; (95% CI)	P trend^b
Sessions per week
None	147	20	0.7	0.7 (0.4–1.3)
<1	647	148	1.3	1.3 (0.8–2.1)
1	591	122	1.1	1.2 (0.7–1.8)
2-3	491	98	1.2	1.1 (0.7–1.8)
≥4	150	28	1.0	1.0 (reference)	0.89
Total exercise^c
No activity	147	20	0.6	0.6 (0.4–0.9)
Low	647	148	1.2	1.1 (0.9–1.5)
Medium	641	128	1.0	0.9 (0.7–1.2)
High	591	120	1.0	1.0 (reference)	0.65

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.