From the Guidelines
The target A1C going into pregnancy should be < 6% if it can be achieved without significant hypoglycemia. This target is based on the most recent evidence from the 2023 standards of care in diabetes, which suggests that an A1C < 6% (42 mmol/mol) has the lowest risk of large-for-gestational-age infants, preterm delivery, and preeclampsia 1. Women planning pregnancy should aim to achieve an A1C below 6% before conception to minimize risks of congenital malformations and adverse pregnancy outcomes.
- Key considerations for achieving this target include:
- Intensive insulin management
- Frequent blood glucose monitoring
- Careful attention to diet and exercise
- Preconception counseling and optimization of glycemic control However, it is essential to note that treatment goals should account for the risk of maternal hypoglycemia in setting an individualized target, and a range of <6% (42 mmol/mol) to <7% (53 mmol/mol) may be considered 1.
- The importance of balancing glycemic control with the risk of hypoglycemia cannot be overstated, as both high and low blood glucose levels can have adverse effects on pregnancy outcomes. Achieving an A1C < 6% requires careful management and monitoring, but the benefits of reduced hyperglycemia-related complications make it a worthwhile goal for women with diabetes who are planning pregnancy.
From the Research
Target A1C Levels in Pregnancy
The target A1C level in pregnancy is a topic of discussion among researchers, with various studies suggesting different optimal levels.
- A study published in 2024 2 found that an optimal hemoglobin A1c cutoff of 5.7% could be used to diagnose diabetes in pregnancy, although this cutoff may not reliably identify diabetes in pregnancy due to its low sensitivity.
- Another study from 2010 3 suggested that aiming for HbA1c levels resembling normal values as closely as possible could help prevent episodes of hypoglycemia and congenital malformations.
- A 2021 study 4 found that to achieve an HbA1c target of less than 6.0%, pregnant women with type 1 diabetes should strive for a time in range (TIR) of greater than 78% during pregnancy.
Comparison of Target A1C Levels
Comparing the target A1C levels mentioned in the studies:
- < 6%: This level is mentioned in the 2021 study 4 as a target for pregnant women with type 1 diabetes, corresponding to a TIR of greater than 78%.
- < 6.5%: This level is mentioned in the 2024 study 2 as a commonly used cutoff to diagnose diabetes in pregnancy, but the study found that a lower cutoff of 5.7% may be more optimal.
- < 7% and < 7.5%: These levels are not specifically mentioned as target A1C levels in the provided studies.
Pregnancy Complications and A1C Levels
The studies also discuss the relationship between A1C levels and pregnancy complications:
- A 2024 study 2 found that an HbA1c level of ≥5.7% increased the risk of maternal insulin use, macrosomia, and shoulder dystocia.
- A 2015 study 5 reviewed the impact of gestational diabetes mellitus (GDM) and fetal macrosomia on birth outcomes, highlighting the increased risk of complications such as shoulder dystocia, clavicle fractures, and brachial plexus injury.
- A 1991 study 6 investigated neonatal macrosomia and hypoglycemia in children of mothers with insulin-treated GDM, finding that macrosomia was significantly correlated to cord C-peptide concentration.