Table 2. Associations of Physical Activity With Preterm Birth^a.

Physical activity metrics	OR (95% CI)
	Model 0	Model 1	Model 2
MVPA, min	0.82 (0.68-0.99)	0.66 (0.43-0.99)	0.64 (0.42-0.98)
FMVPA, %	0.70 (0.56-0.89)	0.70 (0.55-0.89)	0.69 (0.55-0.88)
PAEE, kJ kg–1 d–1	0.86 (0.69-1.09)	0.85 (0.67-1.07)	0.86 (0.68-1.09)

Abbreviations: FMVPA, fraction of physical activity energy expenditure accumulated from moderate-to-vigorous-intensity physical activity; MVPA, moderate-to-vigorous-intensity physical activity; OR, odds ratio; PAEE, physical activity energy expenditure.

^a Logistic regression was used to estimate the ORs and 95% CI for preterm birth per 30-minute increase in MVPA and per SD change in FMVPA and PAEE. A total of 1427 participants were included in the analysis, with a total of 80 cases of preterm delivery identified. Model 0 is an unadjusted model. Model 1 includes adjustments for age, gestational week at baseline, prepregnancy body mass index and PAEE (only for MVPA). Model 2 is the same as model 1 plus household income, educational level, smoking, alcohol drinking, and parity.