Hypoglycemia in Pregnant Women With Type 1 Diabetes

Predictors and role of metabolic control

  1. Lene Ringholm Nielsen, MD12,
  2. Ulrik Pedersen-Bjergaard, MD, DMSC3,
  3. Birger Thorsteinsson, MD, DMSC3,
  4. Marianne Johansen, MD, DMSC24,
  5. Peter Damm, MD, DMSC24 and
  6. Elisabeth R. Mathiesen, MD, DMSC12
  1. 1Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
  2. 2Center for Pregnant Women with Diabetes, Rigshospitalet, Copenhagen, Denmark
  3. 3Endocrinology Section, Nordsjællands Hospital–Hillerød, Hillerød, Denmark
  4. 4Department of Obstetrics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
  1. Address correspondence and reprint requests to Lene Ringholm Nielsen, MD, Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark. E-mail: enel{at}dadlnet.dk

Abstract

OBJECTIVE—In pregnancy with type 1 diabetes, we evaluated occurrence of mild and severe hypoglycemia and analyzed the influence of strict metabolic control, nausea, vomiting, and other potential predictors of occurrence of severe hypoglycemia.

RESEARCH DESIGN AND METHODS—A prospective observational study of 108 consecutive pregnant women with type 1 diabetes was conducted. At 8, 14, 21, 27, and 33 weeks of gestation, patients performed self-monitored plasma glucose (SMPG) (eight/day) for 3 days and completed a questionnaire on nausea, vomiting, hypoglycemia awareness, and history of mild (managed by the patient) and severe (requiring assistance from others) hypoglycemia.

RESULTS—Forty-nine (45%) women experienced 178 severe hypoglycemic events, corresponding to 5.3, 2.4, and 0.5 events/patient-year in the first, second, and third trimesters, respectively. The incidence of mild hypoglycemia was 5.5 events/patient-week in early pregnancy and decreased throughout pregnancy (P < 0.0001), regardless of presence of severe hypoglycemia. Prevalence of nausea and vomiting, mild hypoglycemia, and fraction of SMPG readings ≤3.9 mmol/l did not differ between women with and without severe hypoglycemia. A1C, median SMPG, and fluctuations in SMPG decreased during pregnancy, with no differences between women with and without severe hypoglycemia. Logistic regression analysis identified history of severe hypoglycemia the year preceding pregnancy (odds ratio 3.3 [95% CI 1.2–9.2]) and impaired awareness or unawareness (3.2 [1.2–8.2]) as independent predictors for severe hypoglycemia.

CONCLUSIONS—In pregnancy with type 1 diabetes, the incidence of mild and severe hypoglycemia was highest in early pregnancy, although metabolic control was tighter in the last part of pregnancy. Predictors for severe hypoglycemia were history of severe hypoglycemia and impaired awareness.

Footnotes

  • Published ahead of print at http://care.diabetesjournals.org on 1 October 2007. DOI: 10.2337/dc07-1066.

    Additional information for this article can be found in an online appendix at http://dx.doi.org/10.2337/dc07-1066.

    A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.

    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.

    • Accepted September 23, 2007.
    • Received June 5, 2007.
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  1. Published online before print October 1, 2007, doi: 10.2337/dc07-1066 Diabetes Care January 2008 vol. 31 no. 1 9-14
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