Association of Maternal Diabetes Mellitus with Preterm Infant Outcomes: A Systematic Review and Meta-analysis
Introduction: Maternal diabetes is associated with increased risk of preterm birth; however, it’s association with preterm infant outcomes is unclear. The objective of this study is to systematically review and meta-analyze the association of maternal diabetes with mortality and neonatal morbidities in preterm infants <37 weeks gestational age.
Methods: Medline, PubMed, and Cumulative Index of Nursing and Allied Health Literature databases were searched through August 19, 2019. Studies evaluating neonatal outcomes based on maternal diabetes as the primary exposure variable were included. Data were extracted independently by two co-authors. Modified Newcastle-Ottawa scale was used for the risk of bias assessment. The primary outcome was mortality, whereas secondary outcomes include bronchopulmonary dysplasia (BPD), severe brain injury (intraventricular hemorrhage (IVH) OR IVH or cystic peri-ventricular leukomalacia (PVL)), necrotizing enterocolitis (NEC), and retinopathy of prematurity (ROP).
Results: Of 7956 records identified through database searches, nine studies were included in the study. The risk of bias was low for 6 studies and moderate for 3 studies. No significant association was found between maternal diabetes and mortality (adjusted risk ratio (aRR) 0.90 [95% confidence interval (C.I.) 0.73-1.11]; 6 studies; participants=1191226; I2=83%). Similarly, no significant association was found between maternal diabetes and BPD (aRR 1.00 [95% C.I. 0.92-1.07]; 4 studies; participants=107902; I2=0%), IVH or cystic PVL (aRR 0.91 [95% C.I. 0.80-1.03]; 3 studies; participants=115050; I2=0%), NEC (aRR 1.13 [95% C.I. 0.90-1.42]; 5 studies; participants=;142579; I2=56%) and ROP (aRR 1.17 [95% C.I. 0.85-1.61]; 5 studies; participants=126672; I2=84) (Table 1). A sensitivity analysis where low risk of bias studies were included in the meta-analyses showed similar results, however, the heterogeneity was lower for mortality and ROP (Table 2).
Conclusion: Maternal diabetes is not associated with mortality and severe neonatal morbidities in preterm infants. Future studies should explore the association between the severity of maternal diabetes with preterm neonatal outcomes.