Umbilical Cord Blood Gas Analysis, Obstetric Performance and Perinatal Outcome

Abstract

Objective To analyze if umbilical artery pH (pH_ua) ≤7.00 and umbilical artery blood deficit (BD_ua) ≥12.00 mmol/L are good predictors of adverse neonatal outcomes.

Methods This was an observational, longitudinal and retrospective cohort study, conducted at the department of obstetrics and gynecology of Centro Hospitalar Tondela Viseu between September 2013 and September 2015. Total cohort and subgroup analysis were performed: group A—women with umbilical cord blood gas analysis (UCBGA) performed for non-reassuring fetal cardiotocographic patterns, placental abruption, or shoulder dystocia; and group B—all the others. Assays were made with the software SPSS for Windows, Versions 20.0 and 21.0 (IBM Corp., Armonk, NY, USA).

Results A total of 428 UCBGAs met the inclusion criteria. The group analysis revealed an association between group A and pHua ≤7.00, as well as between BDua ≥12.00 mmol/L and 1st minute Apgar score ≤4 (p = 0.011). After the application of the logistic regression models in the total cohort analysis, pH_ua ≤7.00 had an impact in the occurrence of acute neonatal hypoxia (odds ratio [OR]: 6.71; 95% confidence interval [CI]: 1.21–37.06; p = 0.029); multiparous women had a higher risk of delivering a newborn with first minute Apgar score ≤4 and acute neonatal hypoxia (OR: 5.38; 95% CI: 1.35–21.43; p = 0.017; and OR: 2.66; 95% CI: 1.03–6.89, p = 0.043, respectively); women who had urologic problems during pregnancy had a higher risk of delivering a newborn with 5th minute Apgar score ≤7 (OR: 15.17; 95% CI: 1.29–177.99; p = 0.030); and shoulder dystocia represented a 15 times higher risk of acute neonatal hypoxia (OR: 14.82; 95% CI: 2.20–99.60; p = 0.006).

Conclusion The pH_ua and the BD_ua are predictors of adverse neonatal outcome, and UCBGA is a useful tool for screening newborns at risk. Universal UCBGA should be considered for all deliveries, as it is an accurate screening test for neonatal hypoxia.

Resumo

Objetivo Avaliar se o pH da artéria umbilical (pH_ua) ≤7,00 e o déficit de bases da artéria umbilical (BD_ua) ≥12,00 mmol/L são preditores de desfechos neonatais adversos.

Métodos Estudo observacional, longitudinal e retrospectivo, realizado no Serviço de Ginecolocgia e Obstetrícia do Centro Hospitalar Tondela Viseu durante o período de setembro de 2013 a setembro de 2015. Foi realizada a análise de toda a coorte e de dois subgrupos: grupo A—mulheres cuja gasometria do cordão umbilical (UCBGA, na sigla em inglês) foi realizada por traçado cardiotocográfico não tranquilizador, descolamento prematuro de placenta normalmente inserida, ou distócia de ombros; e grupo B—todas as outras. A análise estatística foi realizada com o programa SPSS for Windows, Versões 20.0 e 21.0 (IBM Corp., Armonk, NY, USA)

Resultados Um total de 428 UCBGAs cumpriram os critérios de inclusão. A análise de grupo revelou uma associação entre o grupo A e pH_ua ≤7,00 (p = 0,002), e entre BD_ua ≥12,00 mmol/L e índice de Apgar ao 1^o minuto ≤4 (p = 0,011). Após a aplicação dos modelos de regressão logística na análise da coorte total, pH_ua ≤7.00 teve impacto na ocorrência de hipóxia neonatal aguda (razão de probabilidade [RP]: 6,71; 95% índice de confiança [IC]: 1,21–37,06; p = 0,029); verificou-se maior risco de recém-nascido com índice de Apgar ao 1^o minuto ≤4 e hipóxia neonatal aguda nas multíparas (RP: 5,38; 95% IC: 1,35–21,.43; p = 0,017; e RP: 2,66; 95% IC: 1,03–6,89; p = 0,043, respectivamente); e de recém-nascido com índice de Apgar ao quinto minuto ≤7 nas mulheres com problemas urológicos na gravidez (RP: 15,17; 95% IC: 1,29–177,99; p = 0,030); e a ocorrência de distócia de ombros aumentou 15 vezes o risco de hipóxia neonatal aguda (RP: 14,82; 95% IC: 2,20–99,60; p = 0,006).

Conclusão O pH_ua e o BD_ua são preditores de desfecho neonatal adverso, e a UCBGA é uma ferramenta útil no rastreio dos recém-nascidos em risco. A realização universal de UCBGA deve ser considerada em todos os partos, visto ser um teste de rastreio objetivo de hipóxia neonatal.

Keywords

Umbilical Cord Blood Gas Analysis - delivery - morbidity - neonatology

Palavras-chave

gasometria do cordão umbilical - parto - morbilidade - neonatologia

Contributions

Ferreira C. S. – elaboration of the database, data search, statistical analysis, and article writing, revision and approval. Melo A. – elaboration of the database, data search, and article revision and approval. Fachada A. H. - data search and article revision; Solheiro H. – data supply and search and article revision and approval; Martins N. N. – study design, elaboration of the database, and article revision and approval.

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