Abstract
Background
To describe the association between maternal hypertension (chronic and gestational, MH) and mortality in very preterm singletons and twins, focusing on how estimates depend on gestational age (GA) and size at birth.
Methods
We estimated relative risks of in-hospital death in 12,320 singletons (MH: 22.4%) and 4381 twins (MH: 10.6%) born at 23–29 weeks in the Italian Neonatal Network (89 hospitals, 2008–2016).
Results
Babies with MH had higher GA and were more frequently small-for-gestational age (SGA), especially singletons. In crude analyses, MH was associated with lower mortality in singletons. In multivariable analyses, the effects of GA and size differed between twins and singletons with and without MH. The best-fitting models included continuous birth weight (rather than SGA) and were stratified by GA. In these models, MH was associated with lower mortality in singletons—but not twins—born after week 25.
Conclusions
In this cohort of very preterm infants, the association between MH and mortality differed between singletons and twins and across strata of GA at birth. These estimates cannot be interpreted causally, but suggest that, from a descriptive/predictive standpoint, singletons with MH born after week 25 have lower mortality than singletons born to women without MH.
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Acknowledgements
Members of the Italian Neonatal Network are listed in Supplemental File S2. The Italian Neonatal Network received non-restricted support from Chiesi Pharmaceuticals, Parma, Italy, for registration of centers to the Vermont -Oxford Network. Chiesi Pharmaceuticals had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
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Both authors have participated in the concept and design; analysis and interpretation of data; and the drafting or revising of the manuscript. Both have approved the manuscript as submitted. No honorarium, grant, or other form of payment was given to anyone to produce the manuscript.
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Gagliardi, L., Basso, O. Maternal hypertension and survival in singletons and twins born at 23–29 weeks: not just one answer…. Pediatr Res 85, 697–702 (2019). https://doi.org/10.1038/s41390-019-0337-4
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DOI: https://doi.org/10.1038/s41390-019-0337-4
