Hypoglycemia in pregnant women with type 1 diabetes: predictors and role of metabolic control.
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.


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.
Nielsen
Lene Ringholm
LR
Department of Endocrinology, Copenhagen University Hospital Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark. enel@dadlnet.dk
Pedersen-Bjergaard
Ulrik
U
Thorsteinsson
Birger
B
Johansen
Marianne
M
Damm
Peter
P
Mathiesen
Elisabeth R
ER
D000328:Adult; D001364:Awareness; D001786:Blood Glucose / Q000378:metabolism; D015190:Blood Glucose Self-Monitoring; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications* / Q000188:drug therapy; D003927:Diet, Diabetic; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000453:epidemiology*; D007328:Insulin / Q000627:therapeutic use; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D011256:Pregnancy Outcome; D012044:Regression Analysis; D012648:Self Care; D011795:Surveys and Questionnaires
D001786:Blood Glucose; D007328:Insulin