Morbidity Risk and Gestational Age Among Full-Term Newborns

Abstract

Introduction: Newborns of Gestational Age (GA) ³ 37 weeks are considered to be full-term, but they might show increased morbidity. 

Objective: To evaluate morbidity risk between newborns 37-38 weeks GA vs those over 39 weeks. 

Patients and Methods: Cohort study of all children born at a private clinic in Buenos Aires between January 1, 2006 and July 31, 2007, product of simple pregnancies and without major congenital abnormalities. A total of 1829 children met the criteria, among which 823 (45%) were 37-38 weeks GA, and 1006 (55%) were 39 weeks or over. The following parameters were recorded: birth route, maternal history and morbidity. Morbidity included at least one of the following: respiratory distress > 2 hours post-birth, use of intravenous solutions, jaundice and use of antibiotics. The association between morbidity and GA was evaluated using Chi-square, and logistical regression was used to evaluate the relationship between newborn morbidity and GA, birth route or maternal hypertension. 

Results: Newborns of 37-38 weeks GA showed higher incidence of each component of morbidity: respiratory distress (OR = 2,55 IC 95% = 1,70-3,82), jaundice (OR = 2,24 IC95% 1,72-2,29), antibiotic use (OR = 2,31 IC 95%= 1,15-4,69) and IV use (OR = 2,29 IC95% = 1,57-3,33). Multivariate analysis showed that GA 37-38 weeks (OR= 1,89 IC95%= 1,31-2,71) and a C-section (OR = 1,65 IC95% = 1,18-2,32) constituted independent predictors of morbidity. 

Conclusion: In this experience, a gestacinal age under 39 weeks increases morbidity risk.