Insulin requirements throughout pregnancy in women with type 1 diabetes mellitus: three changes of direction

Abstract

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 ≤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.

Effect of pregnancy on insulin requirements differs between type 1 and type 2 diabetes: A cohort study of 222 pregnancies

“…3,5,6,10,11 This has been replicated in two recent studies examining women on insulin pumps, which found significant reductions in basal infusion rates at 8-9 weeks of gestation. 5,12 Similarly, in late pregnancy, we observed a 4.1% reduction in dose from the peak TID to delivery.…”

“…2 A number of studies have examined insulin requirements in women with T1DM, depicting a tri-phasic pattern of insulin requirements. [3][4][5][6][7] There is a slight fall in requirements in late first trimester, followed by a progressive increase to 36 weeks of gestation and a slight fall again at term. However, few studies have examined insulin requirements in women with T2DM, and only one study, conducted over 20 years ago, has directly compared requirements between the two groups.…”

Trends in maternal BMI, glycaemic control and perinatal outcome among type 1 diabetic pregnant women in 1989–2008

“…The number of subjects is presented in square brackets if different women especially during the second half of pregnancy [24]. Thus, the increase in maternal BMI might have contributed at least to some extent to the deterioration in late pregnancy glycaemic control.…”

Factors determining insulin requirements in women with type 1 diabetes mellitus during pregnancy: a review

“…A subgroup of women has stable or slightly decreased requirements. 43,49 A smaller percentage have a significant fall in insulin dose. 19,50 Historically, this was attributed to failure of the feto-placental unit.…”

“…The decrease is observed regardless of the adequacy of pre-pregnancy metabolic control. 43 Insulin resistance usually predominates in the third trimester. A subgroup of women has stable or slightly decreased requirements.…”