Risk of macrosomia remains glucose-dependent in a cohort of women with pregestational type 1 diabetes and good glycemic control

Abstract

Macrosomia risk remains high in type 1 diabetes (T1DM) complicated pregnancies. A linear relationship between macrosomia risk and glycated hemoglobin A1c (HbA1c) was described; however, low range of HbA1c has not been studied. We aimed to identify risk factors and examine the impact of HbA1c on the occurrence of macrosomia in newborns of T1DM women from a cohort with good glycemic control. In this observational retrospective one-center study we analyzed records of 510 consecutive T1DM pregnancies (1998–2012). The analyzed group consisted of 375 term singleton pregnancies. We used multiple regression models to examine the impact of HbA1c and self-monitored glucose in each trimester on the risk of macrosomia and birth weight. The median age of T1DM women was 28 years, median T1DM duration—11 years, median pregestational BMI—23.3 kg/m2. Median birth weight reached 3520 g (1st and 3rd quartiles 3150 and 3960, respectively) at median 39 weeks of gestation. There were 85 (22.7 %) macrosomic (>4000 g) newborns. Median HbA1c levels in the 1st, 2nd, and 3rd trimester were 6.4, 5.7, and 5.6 %. Third trimester HbA1c, mean fasting self-monitored glucose and maternal age were independent predictors of birth weight and macrosomia. There was a linear relationship between 3rd trimester HbA1c and macrosomia risk in HbA1c range from 4.5 to 7.0 %. Macrosomia in children of T1DM mothers was common despite excellent metabolic control. Glycemia during the 3rd trimester was predominantly responsible for this condition.

Outcomes, care utilization, and expenditures in adolescent pregnancy complicated by diabetes

“…Additionally, adult women with pregestational diabetes may have cesarean delivery rates as high as 40% and preterm delivery rates as high as 38%, higher than that demonstrated by adolescents in our study. Lastly, fetal weight > 4000 g has been shown to occur in approximately one‐quarter of adult women with pregestational diabetes—higher than our sample, but adolescent pregnancies often have a lower birthweight than adults.…”

Diabetes and Pregnancy

“…Recent retrospective data demonstrated that a mean A1C ≥6.0% in pregnant women with type 2 diabetes was associated with increased risk of neonatal complications (preterm birth, neonatal intensive care unit [NICU] admission, neonatal hypoglycemia and jaundice) compared to women with an A1C <6.0% (82). In women with type 1 diabetes and good glycemic control during pregnancy with an A1C of 4.5% to 7.0%, there is still a linear relationship between third trimester A1C and risk of macrosomia (83).…”

Pregnancy outcomes for women with pre‐pregnancy diabetes mellitus in Australian populations, rural and metropolitan: A review

“…Type 2 DM is increasingly recognised as an important risk factor for poor pregnancy outcomes and is becoming more common. Diabetes type for women giving birth between 2007 and 2017 was type 2 for 12 787 participant women and type 1 for 23 664 participant women; thus, more than one in three women had type 2 DM . The comparable numbers of participant women with type 1 and type 2 DM were 15 407 and 1662 for publications about births between 1987 and 2006; thus in this earlier era, fewer than one in ten women with diabetes were reported as having type 2 .…”

“…Many report between 51%and 77% of women delivered via CS, most of whom (71%) had type 1 DM. Fewer papers report lower CS rates: between 36% (both studies of women with type 2 DM) and 49% where the latter paper and one other did not specify diabetes type . Among study settings with lower CS rates (36–49%), type 1 DM accounted for the majority (93%) of a specified type of PPDM.…”