To what extent will the average risk of severe congenital malformation be increased in infants born to this mother with pregestational diabetes?

A 32-year-old woman, with a 22-year history of type 1 diabetes mellitus, was seen in a pre-pregnancy diabetes clinic. She was a primigravida.

On examination, she had early background retinopathy, her blood pressure was 128/68

mmHg, and her body mass index was 29.7 kg/m2 (18C25).

Investigations:

haemoglobin A1c56 mmol/mol (20C42)

urinary albumin:creatinine ratio1.2 mg/mmol (<3.5)

Over the years her haemoglobin A1c concentration had varied between 58 and 69 mmol/mol. She had impaired awareness of hypoglycaemia and experienced approximately two severe hypoglycaemic events per year. She was worried about the risk of severe congenital malformations in her baby.

To what extent will the average risk of severe congenital malformation be increased in infants born to this mother with pregestational diabetes?
A . two-fold
B . four-fold
C . six-fold
D . eight-fold
E . ten-fold