HbA1c (IFCC)Nutrition library

HbA1c (IFCC)

mmol/mol · Glycaemic

HbA1c reflects average blood glucose over ~8–12 weeks — used for glycaemic screening and diabetes monitoring.

Pregnancy lowers the diagnostic threshold for gestational diabetes in many guidelines. IFCC mmol/mol and NGSP % units differ — always note the assay standard.

How to read it

A single elevated value warrants glucose tolerance testing per local protocol, not diet changes alone.

Trimester context

Stage	For the mother	For the baby
First trimester	—	—
Second trimester	Insulin resistance rises — GDM screening typically occurs 24–28 weeks.	Maternal glycaemia shapes fetal growth trajectory.
Third trimester	Tight control reduces macrosomia and delivery complications.	Late hyperglycaemia affects shoulder dystocia risk.