Antenatal corticosteroid use and clinical evolution of preterm newborn infants

LETTERS TO THE EDITOR

Antenatal corticosteroid use and clinical evolution of preterm newborn infants

Dear. Editor

At the service for which I work there is a very interesting situation with respect of mortality rates: they are high primarily as a result of later death and of newborn babies (NB) with weights that, normally, would not be associated with death in developed countries. IT is true that the use of antenatal corticosteroids has been increasing, and, together with this, the rates of pulmonary problems have reduced greatly, primarily when associated with the use of nasal continuous positive airway pressure (CPAP). Using logistic regression with a multivariate model in a study of four important maternity hospitals in Rio de Janeiro,¹ we found that ventilator usage, birth weight less than 1,250g, maternal vaginal hemorrhage and the male sex were all variables associated with a risk of death, with the use of pulmonary mechanical ventilation the primary indicator of death. The use of antenatal corticosteroid, caesarian delivery and total parenteral nutrition were all associated with reduced mortality. The use of pulmonary surfactant was shown to be associated with a risk of death, but without statistical significance. Currently the greatest cause of death after the fourth day of life is respiratory problems followed by neonatal sepsis. In conclusion, we are reducing hyaline membrane disease and its severity, but if the children remain on mechanical ventilation for more than 4 days they will be contaminated and die from infection. In Table 2 of the article published by the Brazilian Neonatal Research Network (Rede Brasileira de Pesquisas Neonatais)² the observed rates of antenatal corticosteroid use and number of antenatal consultations and were not given – only statistically significant results were shown. Results ought to be listed even when they have no statistical value, since, if there were to be any interaction, these results would become important. Neither were the cut off points for gestational age, birth weight or SNAPPE-II scores given.

Were the article to show an interaction between these results, what might be happening is that the factors associated with reduced mortality, such as the use of antenatal corticosteroid and pulmonary surfactant, are reducing respiratory diseases or making them less serious, but, due to deficient care the children die later, particularly those put on pulmonary mechanical ventilation.

José Luiz Muniz Bandeira Duarte

Adjunct professor, School of Medicine, Universidade Estadual do Rio de Janeiro (UERJ). Coordinator of the Course of Pediatrics. Coordinator of the Neonatal Unit – HUPE – UERJ, Rio de Janeiro, RJ, Brazil.

E-mail: [e-mail] and [e-mail]

References

1. Duarte JLMB, Mendonça GAS. Fatores associados à morte neonatal em recém-nascidos de muito baixo em quatro maternidades no município do Rio de Janeiro. Cad Saude Publica. 2005;21:109-18. No prelo.

2. Rede Brasileira de Pesquisa Neonatais. Uso antenatal de corticosteóide e evolução clínica de recém-nascidos pré-termo. J Pediatr (Rio J). 2004;80:277-84.

Authors' reply

We are grateful to Prof. José Luiz Muniz Bandeira Duarte for his interest in our study¹ and for his courtesy in presenting the conclusions of his work on mortality in four maternity units in Rio de Janeiro.²

In the children analyzed by our study, infection was the most common cause of death according to autopsy reports. Of the 107 deaths, 48 (44%) were associated with infectious problems, 35 (32%) with problems caused by prematurity (pulmonary, hemorrhagic and metabolic problems) and 16 (15%) with perinatal anoxia. The survival time of the children that died are shown in Table 1. It can be seen that there was no association between antenatal corticosteroid use and length of life.

The duration of mechanical ventilation in days for the children that died was 10.3±19.7 and, for those that survived it was 4±11. We agree with Prof. Duarte that the longer duration of mechanical ventilation is associated with a greater incidence of infection. Among our children, the correlation coefficient between mechanical ventilation and positive blood culture was 0.241, with p < 0.001.

Prof. Duarte pointed out that in our paper, in Table 8, the use of antenatal corticosteroids and the number of antenatal consultations were not given, and suggests that, even with no statistical significance, they should have been listed, since these results would become important if they was any interaction. Table 2 lists the values requested.

As can be observed, these variables are a long way from having any impact on the mortality rate of these children.

Cut off points for gestational age, birth weight and SNAPPE-II scores were not given because these parameters were treated as continuous variables.

Without doubt the results presented indicate that the perinatal and postnatal care offered to our preterm children require great improvement and that infection constitutes an enormous challenge to be overcome during these periods. Descriptive and analytical studies of neonatal care are of fundamental importance to improve this care.

Francisco Eulógio Martinez

Brazilian Neonatal Research Network, Department of Pediatrics, School of Medicine of Ribeirão Preto, Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil.

E-mail: [e-mail]

References

1. Rede Brasileira de Pesquisa Neonatais. Uso antenatal de corticosteróide e evolução clínica de recém-nascidos pré-termo. J Pediatr (Rio J). 2004;80:277-84.

2. Duarte JLMB, Mendonça GAS. Fatores associados à morte neonatal em recém-nascidos de muito baixo em quatro maternidades no município do Rio de Janeiro. Cad Saude Publica. 2005;21:109-118. No prelo.

Nas crianças analisadas em nosso estudo, a infecção foi a causa de óbito mais comum segundo os relatórios de necropsia. Dos 107 óbitos, 48 (44%) foram associados a problemas infecciosos, 35 (32%) a problemas relacionados à prematuridade (problemas pulmonares, hemorrágicos e metabólicos) e 16 (15%) a anoxia perinatal. O tempo de vida das crianças que vieram a falecer está apresentado na Tabela 1. Constata-se que não houve associação entre uso antenatal de corticosteróide e tempo de vida das crianças falecidas.

Publication Dates

• Publication in this collection
  16 Feb 2005
• Date of issue
  Dec 2004