Episodic hyperglycaemia in pregnant women with well-controlled Type 1 diabetes mellitus: a major potential factor underlying macrosomia.
OBJECTIVE
To test the common assumption that pregnant women who are sufficiently motivated to achieve very good HbA1c levels will record home blood glucose data accurately.


METHODS
A new device was used to download information from electronic blood glucose meters to assess the extent of selectivity in patient glucose diary-keeping.


RESULTS
In an index case, a woman with excellent ambient HbA1c (5.9%; upper limit of normal 6.1%) was observed to have 68% of preprandial blood glucose readings above the target range of 3.5-6.5 mmol/l and a mean (+/- SD) level of 8.9+/-3.9 mmol/l in the corresponding period. No such impression was conveyed by the home monitoring diary. Six pregnant women with well controlled Type 1 diabetes (mean HbA1c 6.6+/-0.2%) exhibited between 42 and 68% of preprandial readings above the target range.


CONCLUSIONS
The frequency of hyperglycaemia has hitherto been underestimated in well controlled pregnant women whose near-perfect home monitoring record is apparently corroborated by near-normal HbA1c levels. These observations provide a hypothesis for understanding of the disappointing continuance of macrosomia despite excellent HbA1c levels throughout pregnancy.
Kyne-Grzebalski
D
D
Diabetes Unit, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
Wood
L
L
Marshall
S M
SM
Taylor
R
R
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001724:Birth Weight; D001786:Blood Glucose / Q000378:metabolism*; D015190:Blood Glucose Self-Monitoring; D002940:Circadian Rhythm / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology*; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D006943:Hyperglycemia / Q000150:complications*; D007231:Infant, Newborn; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood*; D012307:Risk Factors
D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin