Gestational age at delivery, circumstances at parturition, and prenatal
risk factors affect outcomes of late preterm newborns: results from an
area-based, prospective cohort study.
Abstract
Objective: To identify pregnancies at risk for adverse outcomes in the
late preterm (LP) period, we investigated how gestational age (GA) at
delivery, circumstances at parturition, and specific prenatal risk
factors may affect neonatal outcomes. Study design: Prospective,
area-based cohort study of neonatal morbidity and mortality among
singleton infants born between 34+0 and 36+6 weeks, at 21 L&D units in
Emilia Romagna county, Italy, during 2013-15. The primary neonatal
outcome was a composite of Apgar 5’ ≤ 3, umbilical-cord-blood arterial
pH < 7.0, RDS, TTN, hypoglycemia, sepsis, confirmed seizures,
stroke, IVH, cardiopulmonary resuscitation, invasive respiratory support
and hospitalization ≥ 5 days. Multivariate logistic regression models
were used to respectively investigate the effects on study outcomes of
1) GA at delivery and circumstances at parturition 2) GA at delivery and
prenatal risk factors, after controlling for confounding Results: Among
1867 births, 302, 504 and 1061 infants were born at 34, 35 and 36 weeks,
respectively. There were no neonatal deaths. When studying circumstances
at parturition, an increased risk of composite neonatal outcome was
observed among 34 weeks births, 35 weeks deliveries, and indicated
deliveries. When studying prenatal risk factors, neonatal morbidity was
associated with delivery 34 weeks, birth at 35 weeks, pregestational
diabetes, pPROM, maternal BMI, bleeding and polyhidramnios; instead,
preeclampsia had a protective effect. Conclusion: LP with indicated
deliveries at 34 or 35 weeks, or with specific prenatal risk factors
have worse neonatal outcome when compared to 36. Such differences should
be considered when counseling patients and planning interventions.