Clinical risk factors for preterm birth and evaluating maternal psychology in the postpartum period

Table 1 Comparison of clinical data

Categories		Preterm birth group (n = 60)	Full term group (n = 588)	P value
Age				0.003b
	≥ 35 years old	47	341
	< 35 years old	13	247
Prenatal BMI				0.355
	≥ 23 kg/m2	42	376
	< 23 kg/m2	18	212
History of pre-pregnancy diseases				0.540
	With	5	35
	Without	55	553
Maternal weight change (kg)		8.8 ± 4.7	12.1 ± 3.9	< 0.001c
Parity				0.608
	Primipara	47	441
	Multipara	13	147
Mode of conception				0.005
	Spontaneous conception	52	559
	Artificial insemination	8	29
History of alcohol and tobacco exposure during pregnancy				0.361
	With	5	35
	Without	55	553
Nutritional supplements during pregnancy
	Folic acid supplementation in early pregnancy	47	417	0.252
	Multivitamin supplements in the second trimester	49	441	0.303
	No nutritional supplements during pregnancy	4	41	0.771
Regular physical activity				0.562
	Yes	9	106
	No	51	482
Gestational diabetes mellitus				0.001b
	Yes	11	35
	No	49	553

^bP < 0.01.

^cP < 0.001.

BMI: Body mass index.

Table 2 Comparison of laboratory indexes of patients

Categories	Preterm birth group (n = 60)	Full term group (n = 588)	P value
Reproductive tract infection	13	65	0.023a
Cervical length in the second trimester (mm)	24.7 ± 3.3	32.9 ± 4.8	< 0.001c
White blood cell count (× 109/L)	11.6 ± 2.4	9.5 ± 2.4	< 0.001c
Neutrophil percentage	0.74 ± 0.05	0.86 ± 0.07	< 0.001c

^aP < 0.05.

^cP < 0.001.

Table 3 Comparison of anxiety and depression symptoms

Group	Number of parturients with anxiety	Number of parturients with depression	Number of parturients with anxiety and depression
Preterm birth group (n = 60)	43	45	43
Full term group (n = 588)	191	251	191
χ2	36.232	22.910	36.232
P value	< 0.001c	< 0.001c	< 0.001c

^cP < 0.001.

Table 4 Assignment table

Factors	Assignment
Age	≥ 35 years old = 1, < 35 years old = 0
Maternal weight change (kg)	≥ 10.45 = 1, < 10.45 = 0
Mode of conception	Artificial insemination = 1, spontaneous conception = 0
Gestational diabetes mellitus	With = 1, without = 0
Reproductive tract infection	With = 1, without = 0
Cervical length in the second trimester (mm)	≥ 29.05 = 1, < 29.05 = 0
White blood cell count (× 109/L)	≥ 9.35 = 1, < 9.35 = 0
Neutrophil percentage	≥ 0.85 = 1, < 0.85 = 0
Maternal anxiety and depression	With = 1, without = 0
Delivery status	Premature = 1, full-term = 0

Table 5 Analysis of risk factors for preterm birth

Factors	β	Standard error	χ2	P value	OR	95%CI
						Lower bound	Upper bound
Age	0.650	0.428	2.315	0.128	1.916	0.829	4.429
Maternal weight change	-1.453	0.396	13.456	< 0.001c	0.234	0.108	0.508
Mode of conception	0.967	0.674	2.057	0.151	2.630	0.702	9.855
Gestational diabetes mellitus	1.577	0.586	7.244	0.007b	4.839	1.535	15.254
Reproductive tract infection	0.811	0.500	2.629	0.105	2.250	0.844	5.997
Cervical length in the second trimester	-3.784	0.521	52.804	< 0.001c	0.023	0.008	0.063
White blood cell count	2.255	0.512	19.420	< 0.001c	9.537	3.498	26.004
Maternal anxiety and depression	1.802	0.391	21.301	< 0.001c	6.064	2.821	13.036

^bP < 0.01.

^cP < 0.001.

OR: Odds ratio; CI: Confidence interval.