Aims/hypothesis: The aim of the study was to analyse the insulin requirements of women with type 1 diabetes mellitus throughout pregnancy.
Methods: We have examined the weekly mean blood glucose (mmol/l), insulin requirements (U kg(-1) day(-1)) and total insulin requirements (U/day) in 65 women with type 1 diabetes mellitus and tight metabolic control since before pregnancy (HbA(1c) < or =6.0%).
Results: Both insulin requirement and total insulin requirement displayed a peak in week 9, a nadir in week 16 and a second peak in week 37. For the change in insulin requirement (4.08% per week) and in total insulin requirement (5.19% per week), the sharpest slope was observed from week 16 to week 37. However, two changes of direction took place in the first 11 weeks and eight out of nine episodes of severe hypoglycaemia requiring treatment with glucagon or i.v. glucose took place in the first 16 weeks.
Conclusions/interpretation: Pregnant women with type 1 diabetes mellitus and tight metabolic control since before pregnancy displayed changes in insulin requirement and total insulin requirement with successive changes of direction. The sharpest slope was observed between 16 and 37 weeks, but insulin requirements were more unstable in the first 16 weeks. This information could help patients and physicians to react to changes in glycaemic pattern in a prompt and adequate way.