Neonatal outcomes of live-born term singletons in vertex presentation born to mothers with diabetes during pregnancy by mode of birth: a New South Wales population-based retrospective cohort study

OBJECTIVES: To investigate the association between the mode of birth and adverse neonatal outcomes of macrosomic (birth weight ≥4000 g) and non-macrosomic (birth weight <4000 g) live-born term singletons in vertex presentation (TSV) born to mothers with diabetes (pre-existing and gestational diabetes mellitus (GDM)). DESIGN: A population-based retrospective cohort study. SETTING: New South Wales, Australia. PATIENTS: All live-born TSV born to mothers with diabetes from 2002 to 2012. INTERVENTION: Comparison of neonatal outcomes by mode of birth (prelabour caesarean section (CS) and planned vaginal birth resulted in intrapartum CS, non-instrumental or instrumental vaginal birth). MAIN OUTCOME MEASURES: Five-minute Apgar score <7, admission to neonatal intensive care unit (NICU) or special care nursery (SCN) and the need for resuscitation. RESULTS: Among the 48 882 TSV born to mothers with diabetes, prelabour CS was associated with a significant increase in the rate of admission to NICU/SCN compared with planned vaginal birth. For TSV born to mothers with pre-existing diabetes, compared with non-instrumental vaginal birth, instrumental vaginal birth was associated with increased odds of the need for resuscitation in macrosomic (adjusted ORs (AOR) 2.6; 95% CI (1.2 to 7.5)) and non-macrosomic TSV (AOR 3.3; 95% CI (2.2 to 5.0)). For TSV born to mothers with GDM, intrapartum CS was associated with increased odds of the need for resuscitation compared with non-instrumental vaginal birth in non-macrosomic TSV (AOR 2.3; 95% CI (2.1 to 2.7)). Instrumental vaginal birth was associated with increased likelihood of requiring resuscitation compared with non-instrumental vaginal birth for both macrosomic (AOR 2.3; 95% CI (1.7 to 3.1)) and non-macrosomic (AOR 2.5; 95% CI (2.2 to 2.9)) TSV. CONCLUSION: Pregnant women with diabetes, particularly those with suspected fetal macrosomia, need to be aware of the increased likelihood of adverse neonatal outcomes following instrumental vaginal birth and intrapartum CS when planning mode of birth.