HYPOGLYCEMIA IN PREGNANT WOMEN WITH TYPE 1 DIABETES: PREDICTORS AND ROLE OF METABOLIC CONTROL

Abstract

Objectives: In pregnancy with type 1 diabetes (T1DM) we evaluated occurrence of mild and severe hypoglycemia and analysed influence of strict metabolic control, nausea, vomiting and other potential predictors on occurrence of severe hypoglycemia.

Research, design and Methods: Prospective, observational study of 108 consecutive pregnant women with T1DM. At 8, 14, 21, 27 and 33 weeks gestation they performed self-monitored plasma glucose (SMPG) (8/day) for 3 days and completed a questionnaire on nausea, vomiting, hypoglycemia awareness and history of mild (managed by the patient) and severe hypoglycemia (requiring assistance from others).

Results: 49 (45%) women experienced 178 severe hypoglycemic events, corresponding to 5.3, 2.4 and 0.5 events/patient-year in first, second and third trimester, respectively.

Results: 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. Neither prevalence of nausea and vomiting, mild hypoglycemia or fraction of SMPG readings ≤3.9 mmol/l differed between women with and without severe hypoglycemia. Hemoglobin A1c, median SMPG and fluctuations in SMPG decreased during pregnancy with no differences between women with and without severe hypoglycemia.

Results: Logistic regression analysis identified history of severe hypoglycemia the year preceding pregnancy (OR [95% CI]: 3.3 [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 T1DM the incidence of mild and severe hypoglycemia was highest in early pregnancy although the metabolic control was tighter in last part of pregnancy. Predictors for severe hypoglycemia were history of severe hypoglycemia and impaired awareness.