Plasma C-peptide concentration in women with Type 1 diabetes during early and late pregnancy

H R Murphy, D Elleri, J M Allen, D Simmons, M Nodale, R Hovorka

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11 Citations (Scopus)


AIMS: There are previous suggestions of increased C-peptide concentration in women with Type 1 diabetes during pregnancy. Our aim was to re-evaluate the hypothesis of a pregnancy-induced increase by measuring plasma C-peptide concentration in women with stable blood glucose control under standardized fasting and meal-stimulated conditions.

METHODS: Ten women with Type 1 diabetes; median age 31.1 years, median diabetes duration 19 years, median HbA(1c) 52 mmol/mol (6.9%) were admitted to a clinical research facility for two 24-h visits in early (12-16 weeks) and late (28-32 weeks) pregnancy. Women They ate standardized study meals - 80-g carbohydrate dinner, 60-g carbohydrate breakfast, and fasted between meals and overnight. Closed-loop insulin delivery maintained stable and comparable glycaemic conditions. Paired samples for plasma glucose and C-peptide were obtained.

RESULTS: Plasma glucose levels were comparable in early (median 6.5 mmol/l; interquartile range 5.6-8.6) and late pregnancy (median 7.0 mmol/l; interquartile range 6.1-7.8; P = 0.72). There was no change in fasting or meal-stimulated plasma C-peptide concentration from early to late pregnancy; mean difference 4.0 pmol/l (95% CI -6.0 to 7.0; P = 0.9). Four women had detectable C-peptide; peak (range) early vs. late pregnancy 48.5 (10-115) vs. 40.0 pmol/l (80-105); P = 0.5, which was weakly associated with plasma glucose; R(2) = 0.15, P < 0.0001.

CONCLUSIONS: We found no gestational changes in plasma C-peptide concentration. Previously reported increases may reflect differences in glucose control and/or exogenous insulin doses. This study highlights the importance and challenges of standardizing experimental conditions for accurate plasma C-peptide measurement during Type 1 diabetes pregnancy.

Original languageEnglish
Pages (from-to)e361-4
JournalDiabetic Medicine
Issue number10
Early online date18 Jul 2012
Publication statusPublished - Oct 2012


  • Adult
  • Blood Glucose
  • C-Peptide
  • Diabetes Mellitus Type 1
  • Fasting
  • Female
  • Hemoglobin A Glycosylated
  • Humans
  • Hypoglycemic Agents
  • Insulin
  • Meals
  • Pregnancy
  • Pregnancy Trimester (First)
  • Pregnancy Trimester (Third)
  • Pregnancy in Diabetics

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