Prevalence and risk factors related to preterm birth in Brazil

Leal, Maria do Carmo; Esteves-Pereira, Ana Paula; Nakamura-Pereira, Marcos; Torres, Jacqueline Alves; Theme-Filha, Mariza; Domingues, Rosa Maria Soares Madeira; Dias, Marcos Augusto Bastos; Moreira, Maria Elizabeth; Gama, Silvana Granado

doi:10.1186/s12978-016-0230-0

Reproductive Health

Table 2 Maternal characteristics of spontaneous/pPROM and provider-initiated preterm births as compared to term births

From: Prevalence and risk factors related to preterm birth in Brazil

	Spontaneous/pPROM preterm births		P-value of Spontaneous vs. Term	Provider-initiated preterm births		P-value of Provider-initiated vs. Term	Term births (37–41 weeks)
	n	%	P-value of Spontaneous vs. Term	n	%	P-value of Provider-initiated vs. Term	n	%
Total	1,681	100.0		1,090	100.0		20,677	100.0
Level 1 - Sociodemographic characteristics
Childbirth healthcare
Public	1,439	85.6	0.065	758	69.5	<0.001	16,445	79.5
Private	241	14.3	0.065	332	30.4	<0.001	4,232	20.5
Age (n = 1,678, 1,087 and 20,674)
12 to 19	462	27.5	<0.001	145	13.4	<0.001	3,840	18.6
20 to 34	1,051	62.6		754	69.4		14,692	71.0
≥ 35	165	9.8		188	17.3		2,142	10.4
Skin color (n = 1,681, 1,087 and 20,673)
White	522	31.1	0.312	414	38.1	0.084	7,075	34.2
Black	155	9.2		70	6.5		1,765	8.5
brown	1,003	59.7		603	55.5		11,833	57.3
Marital status (n = 1,678, 1,087 and 20,659)
Live with a partner	1,356	80.4	0.701	927	85.3	0.024	16,818	81.4
Do not live with a partner	321	19.0	0.701	160	14.7	0.024	3,841	18.6
Years of schooling (n = 1,672, 1,083 and 20,582)
≤ 7	544	32.5	<0.001	230	21.2	<0.001	5,349	26.0
8 to 10	469	28.0		222	20.5		5,265	25.6
11 to 14	562	33.6		475	43.9		8,097	39.3
≥ 15	97	5.8		156	14.4		1,871	9.1
Level 2 - Obstetric history
Previous births
0	872	51.9	<0.001	556	51.0	0.032	9,565	46.3
1 to 2	611	36.4		416	38.1		9,029	43.6
≥ 3	197	11.7		118	10.9		2,083	10.1
Previous abortion^a (n = 918, 626 and 12,166)
No	635	69.2	0.206	394	63.0	0.005	8,710	71.6
Yes	283	30.8	0.206	232	37.0	0.005	3,456	28.4
Previous stillbirth or neonatal death^b (n = 810, 534 and 11,113)
No	729	90.1	0.003	468	87.6	<0.001	10,385	93.4
Yes	80	9.9	0.003	66	12.4	<0.001	728	6.6
Previous preterm birth^b (n = 810, 534 and 11,113)
No	584	72.1	<0.001	393	73.7	<0.001	9,992	89.9
Yes	226	27.9	<0.001	140	26.3	<0.001	1,121	10.1
Previous caesarean section^b (n = 810, 534 and 11,113)
No	587	72.5	<0.001	241	45.0	<0.001	6,585	59.2
1	171	21.2		202	37.8		3,465	31.2
≥ 2	51	6.3		91	17.1		1,063	9.6
Level 3 - Maternal/fetal conditions during pregnancy
Adequacy of antenatal care (n = 1,621, 1,061 and 20,175)
Adequate	952	58.7	<0.001	791	74.5	<0.001	13,327	66.1
Inadequate or partially adequate	669	41.3	<0.001	270	25.5	<0.001	6,848	33.9
Pre-pregnancy weight status (BMI) (n = 1,666, 1,078 and 20,604)
Urderweight (≤18,5)	147	8.8	0.100	75	7.0	<0.001	1,656	8.0
Normal weight (18,5-24,9)	1,066	64.0		593	55.0		12,719	61.8
Overweight (25–29,9)	342	20.5		259	24.0		4,326	21.0
Obese (≥30)	112	6.7		152	14.1		1,903	9.2
Smoking during pregnancy
No	1,553	92.4	0.069	1,050	96.3	0.076	19,484	94.3
Yes, less than 10 cigarettes/day	69	4.1		29	2.6		670	3.2
Yes, 10 or more cigarettes/day	58	3.5		12	1.1		523	2.5
Type of pregnancy
Single	1,483	88.2	<0.001	924	84.7	<0.001	20,476	99.0
Multiple	198	11.8	<0.001	166	15.3	<0.001	201	1.0
Obstetric risk
Any below	329	19.6	0.104	720	66.0	<0.001	4,532	21.9
Hypertensive disorders^c	130	7.8	0.112	460	42.2	<0.001	1,992	9.6
Eclampsia	3	0.2	0.063	41	3.8	<0.001	88	0.4
Preexisting Diabetes	16	1.0	0.857	39	3.6	<0.001	194	0.9
Gestational Diabetes	113	6.7	0.115	168	15.4	<0.001	1,657	8.0
Severe chronic diseases^d	12	0.7	0.925	26	2.4	<0.001	162	0.8
Infection at hospital admission for birth	19	1.2	<0.001	13	1.1	<0.001	49	0.2
Abruptio placentae	33	2.0	0.005	71	6.5	<0.001	187	0.9
Placental praevia	8	0.5	0.423	25	2.3	<0.001	77	0.4
IUGR	51	3.1	0.020	217	19.9	<0.001	982	4.7
Major newborn malformation^e	10	0.6	0.025	10	0.9	<0.001	31	0.1

^aExcluded primigravida women from the analysis
^bExcluded nuliparous women from the analysis
^cChronic hypertension, pre-eclampsia and HELLP syndrome
^dChronic renal diseases, chronic cardiac diseases and auto-immune diseases
^eIncluded anencephaly, hidrocephaly, spina bifida, gastrosquisis and other abdominal wall defects, cardiac malformations and multiple malformations

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ISSN: 1742-4755

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