Table 2.

Distribution of births according to maternal, socioeconomic and demographic factors – 1997/98 and 2010 São Luís birth cohorts

Variables	São Luís 1997/98		São Luís 2010		p*
	n= 2.426		n=5.040
	n	%	n	%
Maternal age (years)					<0.001
< 18	317	13.1	437	8.7
18 – 19	396	16.3	504	10.0
20 – 34	1612	66.4	3713	73.7
≥ 35	101	4.2	486	7.6
Maternal schooling (years)					<0.001
0 - 4	416	17.1	227	4.5
5 - 8	1031	42.5	1122	22.3
9 - 11	860	35.5	2920	57.9
≥12	119	4.9	758	11.0
Missing	-	-	13	0.3
Marital status					<0.001
Married	702	28.9	1101	21.8
Consensual union	1137	46.9	2981	59.2
Without a companion	587	24.2	958	19.0
Family income (minimum wages)					<0.001
≤1	398	16.4	736	14.6
1- 3	837	34.5	2040	40.5
>3	1032	42.5	1362	27.0
Missing	159	6.6	902	17.9
Maternal smoking during pregnancy					0.212
No	2322	95.7	4854	96.3
Yes	104	4.3	186	3.7
Occupation of the family head					0.001
Non-manual	500	20.6	1036	20.5
Skilled manual worker	1094	45.1	2050	40.7
Unskilled manual worker	767	31.6	1789	35.5
Missing	65	2.7	165	3.3
Parity					0.627
1	1181	48.7	2404	47.7
2	720	29.7	1549	30.7
≥3	525	21.6	1087	21.6
Adequacy of prenatal care use					<0.001
Adequate	1245	51.3	2988	59.3
Inadequate	947	39.1	1700	33.7
No care	199	8.2	95	1.9
Missing	35	1.4	257	5.1
Category of delivery care					<0.001
Private	268	11.0	801	15.9
Public	2158	89.0	4239	84.1
Type of delivery					<0.001
Vaginal	1608	66.3	2675	53.1
Cesarean	818	34.7	2365	47.9

*p-value calculated by the Pearson chi-square test.