Can hemoglobin A1c in early pregnancy predict adverse pregnancy outcomes in diabetic patients?

Contemporary type 1 diabetes pregnancy outcomes: impact of obesity and glycaemic control

“…The association between glycaemic control and other neonatal morbidity is less evident. A retrospective study of women with pre‐existing diabetes found no association between first trimester HbA 1c levels and adverse maternal or fetal outcomes 7 . More recently, a prospective trial of women with type 1 diabetes in the UK found that HbA 1c levels of 42–46 mmol/mol at 26 weeks' gestation were associated with LGA births, and HbA 1c levels of 48–52 mmol/mol were associated with pre‐term birth, pre‐eclampsia and a need for neonatal glucose infusion 19 .…”

“…There are many gaps in the published literature about pregnancy outcomes for women with type 1 diabetes and their babies. Some studies have not distinguished the risks associated with type 1 and type 2 diabetes, 7 , 8 others have used less informative composite outcomes 7 ‐ 9 or have not accounted for important confounders, such as maternal age, obesity and glycaemic control 5 , 10 . ‐ 12 The interaction between the effects of type 1 diabetes, glycaemic control and body mass index during pregnancy are not well understood, and there are no Australian data on this question.…”

Impact of type 2 diabetes, obesity and glycaemic control on pregnancy outcomes

“…HbA1c is a recognised risk factor for congenital malformation and perinatal mortality, but the association with other pregnancy outcomes is less clear . A retrospective study of T2D in the US (2003–2011) found that early pregnancy HbA1c was not a good predictor of composite maternal or fetal outcomes . Conversely, third trimester HbA1c was a risk factor for LGA in a prospective cohort with pre‐existing diabetes in East Anglia (2006–2009) .…”

Fetal sonographic characteristics associated with shoulder dystocia in pregnancies of women with type 1 diabetes

“…A population‐based study from the UK showed that strict glycemic control around the time of conception predicted appropriate fetal growth, whereas poor glycemic control in late gestation predicted fetal overgrowth . A smaller retrospective cohort study from 2014 of vaginal deliveries in women with diabetes suggested that every fourth woman with HbA1c ≥8.5% in early pregnancy experienced shoulder dystocia compared with 2% in women with HbA1c <8.5% . We observed higher HbA1c levels in early pregnancy in women with shoulder dystocia, but comparable glycemic control later in pregnancy.…”