Glycemic thresholds for spontaneous abortion and congenital malformations in insulin-dependent diabetes mellitus

Obstet Gynecol. 1994 Oct;84(4):515-20.


Objective: To test the hypothesis that women with insulin-dependent (type I) diabetes have a threshold of glycemic control in early pregnancy for increased risks of spontaneous abortion and congenital malformations.

Methods: Receiver-operating characteristic (ROC) curves were formed for the occurrence of abortion and malformations as a function of the median first-trimester preprandial blood glucose concentration and the first measured glycohemoglobin concentration in pregnant women with type I diabetes.

Results: Fifty-two of the 215 women (24%) who enrolled before 9 weeks' gestation had spontaneous abortions. Six percent of the women enrolled before 14 weeks had infants with major congenital malformations. Thresholds for an increased risk of abortion and malformations were a median first-trimester blood glucose concentration of 120-130 mg/dL or an initial glycohemoglobin concentration of 12-13% (6.2-7.5 standard deviations above the normal mean).

Conclusions: Type I diabetic women with initial glycohemoglobin concentrations in pregnancy above 12% or median first-trimester preprandial glucose concentrations above 120 mg/dL have an increased risk of abortion and malformations. Below these glycemic thresholds, the risks are comparable to those in nondiabetic women.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Abortion, Spontaneous / epidemiology*
  • Adult
  • Blood Glucose / metabolism*
  • Congenital Abnormalities / epidemiology*
  • Diabetes Mellitus, Type 1 / blood*
  • Female
  • Glycated Hemoglobin A / analysis
  • Humans
  • Infant, Newborn
  • Pregnancy
  • Pregnancy Trimester, First
  • Pregnancy in Diabetics / blood*
  • Prospective Studies
  • ROC Curve
  • Risk Factors
  • Sensitivity and Specificity


  • Blood Glucose
  • Glycated Hemoglobin A