Table 3.

Newly occurring paternal/maternal depression and risks of spontaneous/medically indicated very (≤31 weeks of gestation) and moderately (32–36 weeks of gestation) preterm birth (n = 366 322)

	Very preterm				Moderately preterm
	Spontaneous		Medically indicated		Spontaneous		Medically indicated
	(n = 1311)		(n = 823)		(n = 10 804)		(n = 3 818)
	OR (95% CI)		OR (95% CI)		OR (95% CI)		OR (95% CI)
	Model 1	Model 2	Model 1	Model 2	Model 1	Model 2	Model 1	Model 2
Paternal depression
No depression	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
New depression	1.26 (0.89–1.79)	1.09 (0.73–1.62)	1.69 (1.15–2.48)	1.76 (1.17–2.66)	1.12 (0.98–1.27)	1.09 (0.94–1.25)	1.31 (1.08–1.60)	1.26 (1.02–1.55)
Recurrent depression	1.26 (0.89–1.78)	1.22 (0.84–1.77)	1.12 (0.69–1.80)	1.00 (0.58–1.73)	1.08 (0.95–1.23)	1.07 (0.93–1.22)	1.11 (0.89–1.37)	1.02 (0.81–1.29)
Maternal depression
No depression	1.00	1.00	1.00	1.00	1.00	1.00	1.00	1.00
New depression	1.54 (1.19–1.99)	1.25 (0.92–1.69)	1.48 (1.06–2.06)	1.22 (0.84–1.78)	1.20 (1.08–1.33)	1.20 (1.07–1.33)	1.71 (1.48–1.97)	1.70 (1.47–1.98)
Recurrent depression	1.15 (0.89–1.48)	1.06 (0.79–1.41)	1.22 (0.89–1.66)	1.17 (0.84–1.63)	1.42 (1.30–1.54)	1.38 (1.26–1.51)	1.60 (1.41–1.83)	1.51 (1.31–1.73)

Model 1: adjusted for calendar year of birth, maternal age, parity, paternal education, and paternal age (≥45 years). Model 2: adjusted for the variables listed in model 1, plus smoking, BMI, and also chronological order of parental depression. Note: parental depression was measured in the 12 months before conception up until 24 weeks of gestation. Model 1 is based on 366 322 observations with complete information on covariates. Model 2 is based on 342 111 observations with complete information on covariates. Bold numbers represent Wald test P‐values less than 0.05.