Table 3.

Selected results from case-crossover analysis: association between acute events and the risk of spontaneous preterm delivery.

	Discordant pair ratio	Odds ratio (95% CI)
Any stress	5/8	0.6 (0.2, 1.9)
At least very stressful event	3/6	0.5 (0.1, 2.0)
Any work	4/32	0.1 (0.04, 0.4)
Any sexual activity	6/1	6.0 (0.7, 49.8)
Any exercise	21/17	1.2 (0.7, 2.3)
5+ METs	9/12	0.8 (0.3, 1.8)
Ate spicy food	14/2	7.0 (1.6, 30.8)
Skipped one or more meals	13/3	4.3 (1.2, 15.2)
Disturbed sleep	18/4	4.5 (1.5, 13.3)