Forty-eight-hour first-trimester glucose profiles in women with type 1 diabetes mellitus: a report of three cases of congenital malformation.
OBJECTIVE
Despite modern methods of treatment and near-normal HbA(1c) levels, women with type 1 diabetes mellitus are still at risk of having an infant with a congenital malformation (CM). We hypothesised that HbA(1c) levels are too gross a measure of glycaemic control and used a continuous glucose monitoring system (CGMS) to determine the diurnal glucose profiles during the first trimester of pregnancy. We present three cases of infants with a CM.


METHODS
Fifty-three women with type 1 diabetes used the CGMS for 48 h in the first trimester of pregnancy. Three of them gave birth to infants with a CM. HbA(1c) levels were determined at the time of the CGMS measurement and 6 to 8 weeks later.


RESULTS
The HbA(1c) levels at the time of the CGMS measurement were 6.0, 6.5 and 7.8% (normal range 4.0-6.0%) in the three women. The 48-h diurnal glucose profiles of these women showed a large variability with frequent hyperglycaemic episodes.


CONCLUSIONS
HbA(1c) levels are too gross a measure of glycaemic control to identify women at risk of giving birth to an infant with a CM. Even in women with normal or near-normal HbA(1c) levels, the diurnal glucose profiles reveal intermittent hyperglycaemic episodes that may cause the CM.
Kerssen
Anneloes
A
Department of Perinatology and Gynaecology, University Medical Centre Utrecht, The Netherlands. a.kerssen@umutrecht.nl
de Valk
Harold W
HW
Visser
Gerard H A
GH
D000328:Adult; D015415:Biomarkers; D001786:Blood Glucose / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D000013:Congenital Abnormalities / Q000175:diagnosis / Q000209:etiology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood*; D011254:Pregnancy in Diabetics; D015203:Reproducibility of Results
D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human