Pregnancy-Induced Rise in Serum C-Peptide Concentrations in Women With Type 1 Diabetes
- Lene Ringholm Nielsen, MD, PHD1,2,
- Jens F. Rehfeld, MD, DMSC3,
- Ulrik Pedersen-Bjergaard, MD4,
- Peter Damm, MD, DMSC1,5 and
- Elisabeth R. Mathiesen, MD, DMSC1,2
- 1Center for Pregnant Women with Diabetes, Rigshospitalet, Faculty of Health Sciences, Copenhagen, Denmark;
- 2Department of Endocrinology, Rigshospitalet, Faculty of Health Sciences, Copenhagen, Denmark;
- 3Department of Clinical Biochemistry, Rigshospitalet, Faculty of Health Sciences, Copenhagen, Denmark;
- 4Endocrinology Section, Department of Cardiology and Endocrinology, Hillerød Hospital, Hillerød, Denmark;
- 5Department of Obstetrics, Rigshospitalet, Faculty of Health Sciences, Copenhagen, Denmark.
- Corresponding author: Lene Ringholm Nielsen, enel{at}dadlnet.dk.
Abstract
OBJECTIVE The purpose of this study was to investigate whether pregnancy induces increased insulin production as a marker of improved β-cell function in women with long-term type 1 diabetes.
RESEARCH DESIGN AND METHODS This was a prospective study of 90 consecutive pregnant women with type 1 diabetes. At 8, 14, 21, 27, and 33 weeks blood samples were drawn for measurements of A1C, C-peptide, and serum glucose. C-peptide (detection limit: 6 pmol/l) was considered stimulated at a corresponding serum glucose concentration ≥5.0 mmol/l. GAD antibody concentration was determined at 8 and 33 weeks in 35 women.
RESULTS C-peptide concentrations gradually increased throughout pregnancy regardless of serum glucose concentrations in the 90 women with a median duration of diabetes of 17 years (range 1–36 years). Among 35 women with paired recordings of stimulated C-peptide, C-peptide production was detectable in 15 (43%) at 8 weeks and in 34 (97%) at 33 weeks (P < 0.0001), and median C-peptide gradually increased from 6 to 11 pmol/l (P = 0.0004) with a median change of 50% (range −50 to 3,271%) during pregnancy. GAD antibodies were present in 77% with no change from 8 to 33 weeks (P = 0.85). Multivariate regression analysis revealed a positive association between the absolute increase in C-peptide concentrations during pregnancy and decreased A1C from 8 to 33 weeks (P = 0.003).
CONCLUSIONS A pregnancy-induced increase in C-peptide concentrations in women with long-term type 1 diabetes was demonstrated, even in women with undetectable C-peptide concentrations in early pregnancy. This increase is suggestive of improved β-cell function and was associated with improvement in glycemic control during pregnancy.
Footnotes
-
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
- Received October 8, 2008.
- Accepted February 12, 2009.
-
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.
- © 2009 by the American Diabetes Association.
