Forty-eight-hour first-trimester glucose profiles in women with type 1 diabetes mellitus: a report of three cases of congenital malformation

Prenat Diagn. 2006 Feb;26(2):123-7. doi: 10.1002/pd.1340.

Abstract

Objective: Despite modern methods of treatment and near-normal HbA(1c) levels, women with type 1 diabetes mellitus are still at risk of having an infant with a congenital malformation (CM). We hypothesised that HbA(1c) levels are too gross a measure of glycaemic control and used a continuous glucose monitoring system (CGMS) to determine the diurnal glucose profiles during the first trimester of pregnancy. We present three cases of infants with a CM.

Methods: Fifty-three women with type 1 diabetes used the CGMS for 48 h in the first trimester of pregnancy. Three of them gave birth to infants with a CM. HbA(1c) levels were determined at the time of the CGMS measurement and 6 to 8 weeks later.

Results: The HbA(1c) levels at the time of the CGMS measurement were 6.0, 6.5 and 7.8% (normal range 4.0-6.0%) in the three women. The 48-h diurnal glucose profiles of these women showed a large variability with frequent hyperglycaemic episodes.

Conclusions: HbA(1c) levels are too gross a measure of glycaemic control to identify women at risk of giving birth to an infant with a CM. Even in women with normal or near-normal HbA(1c) levels, the diurnal glucose profiles reveal intermittent hyperglycaemic episodes that may cause the CM.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biomarkers
  • Blood Glucose / metabolism*
  • Circadian Rhythm / physiology*
  • Congenital Abnormalities / diagnosis
  • Congenital Abnormalities / etiology*
  • Diabetes Mellitus, Type 1 / blood*
  • Diabetes Mellitus, Type 1 / complications
  • Female
  • Glycated Hemoglobin A / analysis
  • Humans
  • Infant, Newborn
  • Male
  • Pregnancy
  • Pregnancy Trimester, First / blood*
  • Pregnancy in Diabetics*
  • Reproducibility of Results

Substances

  • Biomarkers
  • Blood Glucose
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human