Table 3. Prevalence of prematurity according to national macro-region, mother and gestational characteristics, comparing the pre-pandemic and pandemic periods, Brazil, 2011-2021.

Variables	Average prevalence (%) Pre-pandemic period: 2011-2019	95%CIa	Average prevalence (%) Pandemic period: 2020-2021	95%CIa
Brazil	11.0	10.6;11.5	11.3	11.2;11.4
North	11.6	11.0;12.1	11.9	11.5;12.2
Northeast	11.0	10.8;11.2	11.2	10.6;11.8
Southeast	10.8	10.3;11.3	11.3	11.0;11.6
South	11.0	10.4;11.6	11.3	10.7;11.9
Midwest	10.8	10.5;11.0	11.2	10.9;11.6
Mother’s age (in full years)
10-19	12.6	12.1;13.1	12.5	11.6;13.3
20-29	10.0	9.5;10.4	10.1	10.0;10.2
30-39	11.5	11.1;11.9	12.1	11.5;12.8
≥ 40	14.8	14.3;15.3	15.7	14.6;16.8
Mother’s schooling (in complete years of study)
1-3	12.7	12.2;13.3	13.6	10.9;16.3
4-7	12.1	11.6;12.6	12.6	12.1;13.1
8-11	10.7	10.2;11.1	11.1	11.0;11.2
≥ 12	10.8	10.4;11.2	11.1	10.9;11.3
Mother’s race/skin color
White	10.9	10.4;11.4	11.3	10.8;11.8
Black	11.8	11.5;12.2	11.7	11.6;11.8
Mixed race	11.0	10.6;11.3	11.2	10.9;11.4
Asian	11.1	10.7;11.6	11.7	10.9;12.5
Indigenous	14.4	13.6;15.3	14.1	12.7;15.4
Type of pregnancy
Single	10.1	9.6;10.5	10.2	10.1;10.3
Twin	55.4	53.2;57.5	60.8	54.9;66.7
Number of prenatal care visits
1-3	21.9	21.2;22.5	21.6	17.9;25.3
4-6	16.4	15.5;17.4	18.0	12.7;23.4
≥ 7	7.9	7.5;8.3	8.5	8.0;8.9
Type of delivery
Vaginal	11.1	10.5;11.6	10.7	9.4;12.0
Cesarean section	11.0	10.6;11.4	11.8	10.7;12.9

a) 95%CI: 95% confidence interval.