Table 2.

Univariate analysis of the factors contributing to a high EPDS score

		High-score group EPDS ≥ 9 (N = 284)		Low-score group EPDS ≤ 8 (N = 1341)
		Average		Average		P-value*	T-value
Maternal	Age at birth (year)	33.0		33.1		0.688	-0.40
Birth	Gestational age at birth (weeks)	38.1		38.0		0.141	1.47
Neonate	Birth weight (g)	2,809		2,826		0.540	-0.61
	Z-score of birth weight	0.26		0.44		0.022	-2.3
		N	%	N	%	P-value*	Chi-square statistic
Maternal	Young pregnant women (≤ 19 years)	5	1.8	18	1.3	0.588	0.29
	Advanced maternal age (≥ 40 years)	30	10.6	119	8.9	0.370	0.80
	Primipara	167	58.8	692	50.9	0.015	5.93
	Multiple pregnancy	4	1.4	21	1.6	0.845	0.04
	Pregnancy complication	151	53.2	763	56.9	0.250	1.32
	Underlying maternal disease	153	53.9	591	44.1	0.003	9.01
	Mental disorder	46	16.2	39	2.9	0.000	83.5
	Maternal transport	40	14.1	256	19.1	0.047	3.94
Birth	Preterm birth	43	15.1	275	20.5	0.038	4.29
	Urgent cesarean section	67	23.6	328	24.5	0.757	0.10
Neonate	Low birth weight (< 2500 g)	71	25.0	320	23.9	0.684	0.17
	Light for date	29	10.2	88	6.6	0.031	4.67
	Hospitalization at NICU	162	57.0	739	55.1	0.551	0.34
	Neonatal transport	5	1.8	7	0.5	0.027	4.91
Lactation	Exclusive breastfeeding	81	28.5	579	43.2	0.000	21.02
	Bottle-feeding	51	18.0	98	7.3	0.000	31.91
Social	No partner	8	2.8	23	1.7	0.218	1.52
	Welfare	2	0.7	2	0.1	0.086	2.94
	Late visit	7	2.5	10	0.7	0.010	6.69

T-test was used to compare mean values (age at birth, gestational age of birth, birth weight, Z-score of birth weight), and chi-square test was used for other items

EPDS: Edinburgh Postnatal Depression Scale; SD: standard deviation; Maternal transport: woman was transferred to our hospital from another hospital due to complications; Light for date: birth weight was below the 10th percentile; NICU: neonatal intensive care unit; Neonatal transport: the newborn was transported from our hospital to another hospital due to complications; Late visit: the first visit was after 22 weeks

* statistically significant (P < 0.05); Bold: statistically significant