Abstract
Background: The increase on multiple births has been associated with a rise of low birth weight rates (LBW) in developed countries. In Brazil, despite the steady increase of LBW rate in some settings, there is no evaluation of the impact of multiple births on LBW rates.
Objective: To investigate the influence of multiple births on trends of low birth weight rates in the city of Porto Alegre, one of the most developed areas in the South of the country. Methods: This is a registry-based study of all live births from 1993 to 2002. The data were obtained from the SINASC (live birth information system). The Chi-Square test for trend was calculated to identify trends in LBW and multiple birth rates. The percent increase in LBW rate per year was estimated in a logistic regression model taking LBW as the dependent variable and year as the independent variable. The impact of multiple births on LBW trends was assessed by extending the former logistic regression model, including adjustment for multiple births.
Results: A total of 230,615 live-births were included. The LBW rate increased steadily from 9.2% to 10.3 (p<0.01) and the multiple birth rate rose from 1.7% to 2.3% (p<0.001). The LBW rate increased by 7.6 percentage points among multiple births (p<0.05) and by a 0.7 percentage point among singletons (p>0.05). The low birthweight rate increased 0.9% per year. When adjusted for multiple births the increase in the low birth weight rate was 0.7% per year, implying that multiple births accounted for 20.5% of the increase in the low birth weigth rate over the period.
Conclusion: LBW rate increased significantly. This rise was greatly influenced by a simultaneous increase in multiple births, linked to the widespread introduction of new reproduction technologies.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Goldani, M., Homrich, C., Silva, A. et al. 149 Impact of Multiple Births on Low Birth Weight Rate in Porto Alegre, Brazil. Pediatr Res 58, 380 (2005). https://doi.org/10.1203/00006450-200508000-00178
Issue Date:
DOI: https://doi.org/10.1203/00006450-200508000-00178