Comparison of Neonatal Morbidity and Mortality Following Spontaneous and Medically Indicated Preterm Births: A Retrospective Population-Based Study Using Data from the Slovenian National Perinatal Information System 2013-2018.

BACKGROUND This retrospective population-based study analyzed data from the Slovenian National Perinatal Information System (NPIS) between 2013 and 2018 to compare neonatal morbidity and mortality following spontaneous and medically indicated preterm births. MATERIAL AND METHODS Retrospective population-based cohort. Entries to the NPIS database were searched by gestational age (GA) <37 weeks in Slovenia between 2013 and 2018. Of 9200 (6252 following spontaneous birth, 2948 following medically indicated) neonates included, 1358 were born at extremely to very preterm GA (998 following spontaneous birth, 360 following medically indicated). Logistic regression analysis was used to examine the association between neonatal mortality and composite severe neonatal morbidity and preterm birth type (spontaneous vs medically indicated) controlling for potential confounding variables. Analysis was first performed for all preterm births (GA 22 0/7 to 36 6/7) and later only for extremely to very preterm births (GA 22 0/7 to 31 6/7). RESULTS Neonatal mortality was significantly lower following spontaneous preterm birth at extremely to very preterm GA (odds ratio [OR] 0.34; 95% confidence interval [CI] [0.14, 0.81]), while there was no association in all preterm births group (OR 0.56; 95% CI [0.26, 1.20]). No significant correlation between preterm birth type and neonatal morbidity was found (OR 0.76; 95% CI [0.54, 1.09] for all preterm births and OR 0.71; 95% CI [0.47, 1.07] for extremely to very preterm births). CONCLUSIONS In this population study from Slovenia between 2013 and 2018, medically indicated preterm births at <32 weeks of GA were associated with significantly increased neonatal mortality but not neonatal morbidity.