Objectives To estimate the national rate of early-term live births in Brazil and to evaluate the effect of birth at 37 and 38 weeks’ gestation, as compared with 39 and 40 weeks’ gestation on infant outcomes according to precursors of birth and the existence of maternal/fetal medical conditions.
Design National perinatal population-based cohort study.
Setting 266 maternity services located in the five Brazilian macroregions.
Participants 18 652 singleton live newborns from 37 0/7 to 40 6/7 weeks of gestation.
Main outcome measures Resuscitation in delivery room, oxygen therapy, transient tachypnoea, admission to neonatal intensive care unit (NICU), hypoglycaemia, use of antibiotics, phototherapy, phototherapy after hospital discharge, neonatal death and breastfeeding.
Results Early terms accounted for 35% (95% CI 33.4% to 36.7%) of all live births. Among provider-initiated births in women without medical conditions, infants of 37 and 38 weeks’ gestation had higher odds of oxygen therapy (adjusted OR (AOR) 2.93, 95% CI 1.72 to 4.98 and AOR 1.92 95% CI 1.18 to 3.13), along with admission to NICU (AOR 2.01, 95% CI 1.18 to 3.41 and AOR 1.56, 95% CI 1.02 to 2.60), neonatal death (AOR 14.40, 95% CI 1.94 to 106.69 and AOR 13.76,95% CI 2.84 to 66.75), hypoglycaemia in the first 48 hours of life (AOR 7.86, 95% CI 1.95 to 31.71 and AOR 5.76, 95% CI 1.63 to 20.32), transient tachypnoea (AOR 2.98, 95% CI 1.57 to 5.65 and AOR 2.12, 95% CI 1.00 to 4.48) and the need for phototherapy within the first 72 hours of life (AOR 3.59, 95% CI 1.95 to 6.60 and AOR 2.29, 95% CI 1.49 to 3.53), yet lower odds of breastfeeding up to 1 hour after birth (AOR 0.67, 95% CI 0.53 to 0.86 and AOR 0.87, 95% CI 0.76 to 0.99) and exclusive breastfeeding during hospital stay (AOR 0.68, 95% CI 0.51 to 0.89 and AOR 0.84, 95% CI 0.71 to 0.99).
Conclusion Birth at 37 and 38 weeks’ gestation increased the risk of most adverse infant outcomes analysed, especially among provider-initiated births and should be avoided before 39 weeks’ gestation in healthy pregnancies.
- neonatal outcomes
- early term birth
- caesarean section
- gestational age
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Contributors MCL, APE-P and MN-P designed the study, analysed and interpreted the data, wrote, revised, read and approved the final version of the manuscript. RD, MABD, MEM, MF, SGNG collaborated in the data analysis, wrote, revised, read and approved the final version of the manuscript.
Funding This work was supported by the Ministério da Ciência, Tecnologia e Inovação - Conselho Nacional de Desenvolvimento Científico e Tecnológico; Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro and Fundação Oswaldo Cruz. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
Competing interests None declared.
Patient consent Obtained.
Ethics approval This study was carried out in accordance with the National Health Council Resolution n. 196/96. The ethics committee of the Sérgio Arouca National School of Public Health, Oswaldo Cruz Foundation (CEP/ENSP) approved this study under the research protocol CAAE: 0096.0.031.000-10 (approval date: May 11th 2010). Before starting the baseline interview, the interviewer read aloud the Free and Informed Consent Form and received written consent of the interviewee. The participant then received a copy containing all details of the research, including the contact of the national and state coordinators. All hospital directors also gave written informed consent.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data of Birth in Brazil Study can be shared for specific research questions that are available from the corresponding author on request.
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