High frequency of antithyroid autoantibodies in pregnant women at increased risk of gestational diabetes mellitus.
BACKGROUND
Thyroid autoantibodies (ThyAb) and subclinical hypothyroidism occur more frequently in pregnant women with insulin-dependent diabetes mellitus than in healthy pregnant women. Few studies have investigated the presence of ThyAb in women with gestational diabetes mellitus (GDM), and no significant association between diabetes in pregnancy and thyroid function has been reported.


OBJECTIVE
To assess the thyroid biochemical profile and estimate the prevalence of ThyAb in a group of pregnant women at increased risk of GDM due to family and personal risk factors, and to investigate the relationship between a positive family history of diabetes or thyroid diseases and the eventual presence of ThyAb during pregnancy.


METHODS
Oral glucose tolerance, serum ThyAb and thyroid function were evaluated in 181 pregnant women with increased risk for GDM (study group). Seventeen healthy pregnant women without risk factors for GDM and with a normal glucose tolerance were recruited as controls.


RESULTS
The women who developed GDM showed a mean free thyroxine concentration significantly lower than that observed in the healthy pregnant women and in those with impaired gestational glucose tolerance and normal glucose tolerance. Twenty-nine of the 181 women in the study group (16%) were ThyAb positive. However, the risk of being ThyAb positive during pregnancy was three times greater in the women with positive family history of both diabetes mellitus and thyroid disease than in those with no family history of these conditions.


CONCLUSIONS
This study showed that women with increased risk of GDM, mostly those with family history of diabetes mellitus and thyroid disease, also have an increased risk of being ThyAb positive during pregnancy. It also highlighted the importance of evaluating thyroid function in pregnant women with impaired glucose tolerance, in view of their increased risk of subclinical hypothyroidism.
Olivieri
A
A
Laboratory of Metabolism and Pathological Biochemistry, Istituto Superiore di Sanità, Rome, Italy. olivieri@iss.it
Valensise
H
H
Magnani
F
F
Medda
E
E
De Angelis
S
S
D'Archivio
M
M
Sorcini
M
M
Carta
S
S
Baccarini
S
S
Romanini
C
C
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D016640:Diabetes, Gestational / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000276:immunology; D006801:Humans; D049590:Postpartum Period / Q000097:blood / Q000502:physiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000276:immunology; D012016:Reference Values; D012307:Risk Factors; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000276:immunology*; D013974:Thyroxine / Q000097:blood
D001323:Autoantibodies; D001786:Blood Glucose; D013974:Thyroxine