Table 2.

Stress-related factors that were associated relative risk of PTB

Stress-related factors reported by expectant mother	Reference group	N	Comparison group	N	Relative risk of PTB	95% CI
Prenatal factors
General anxiety	Low anxious	93	High anxious	14	8.9	2.0, 39.6
			Moderate anxious	107	2.6	0.7, 9.6
Sadness	Low sadness	122	High sadness	11	1.9	0.2, 15.4
			Moderate sadness	81	2.8	1.0, 7.5
Frequency of pain experience	No pain	104	High pain frequency	27	5.7	1.7, 17.0
			Moderate pain frequency	83	1.3	0.4, 4.3
Tired/fatigued–past 3 y	Low tired/fatigued	50	High tired/fatigue	41	3.7	1.09, 13.5
			Moderate tired/fatigue	123	0.8	0.2, 3.3
Self-rated health (SRH) –past 3 y	High SRH	144	Low SRH	0	Insuff. data
			Moderate SRH	70	2.9	1.1, 7.7
Experienced divorce (self)	No divorce	182	Experienced divorce	31	2.9	1.1, 7.8
Experienced major illness (self)	No major illness	176	Experienced illness	37	2.6	1.0, 7.0
Perinatal factors
Perceived risk of birth complications	Low perceived risk	101	High perceived risk	68	4	1.6, 10.1
			Moderate perceived risk	104	1.5	0.5, 4.1
Self-rated health (SRH)–current	High SRH	147	Low SRH	2	Insuff. data
			Moderate SRH	64	2.3	1.0, 6.7
Protective factors
Happiness–past 3 y	High happiness	163	Low happiness	2	9.1	1.25, 71.5
			Moderate happiness	50	3	1.1, 7.5
Support from parents and siblings	High support	167	Low support	16	3.5	0.9, 12.9
			Moderate support	33	3.4	1.2, 9.5
Support from father of baby	High support	194	Low support	3	Insuff. data
			Moderate support	17	3.3	1.1, 9.9

Abbreviations: CI, confidence interval; Insuff., insufficient; PTB, preterm birth.