Thyroid peroxidase antibodies in pregnant women with type 1 diabetes: impact on thyroid function, metabolic control and pregnancy outcome.
OBJECTIVE
In pregnant women with type 1 diabetes, we evaluated whether the presence of thyroid peroxidase autoantibodies (anti-TPO) was associated with changes in thyroid function, metabolic control and pregnancy outcome.


METHODS
Prospective study, Denmark.


METHODS
Ninety-six consecutive pregnant women with type 1 diabetes. Twenty-five healthy pregnant controls.


METHODS
At 8, 14, 21, 27 and 33 weeks, the diabetic women self-monitored plasma glucose (SMPG) (8/day) for 3 days and had blood samplings obtained.


METHODS
Thyroid-stimulating hormone (TSH), free thyroxin (T4), hemoglobin A1C (HbA1C), anti-TPO, pregnancy outcome.


RESULTS
Anti-TPO was detected in 31 (32%) of the pregnant diabetic women compared with two women (8%) in the healthy controls (p=0.015). The presence of anti-TPO was associated with higher TSH at 8 (p<0.0001) and 14 weeks (p<0.05) and lower free T4 at 8 weeks (p<0.05) compared with anti-TPO negative women. Twenty untreated anti-TPO positive women had higher TSH compared with untreated, anti-TPO negative women (p<0.05), but comparable free T4. At inclusion, 25% had TSH above the recommended treatment goal for levothyroxine (TSH>2.5 mIU/l), most prevalently among anti-TPO positive women. Sixteen women (17%) were treated for thyroid disorder during pregnancy. No differences were detected between the diabetic women with and without anti-TPO regarding HbA1C, insulin dose, median SMPG or pregnancy outcome.


CONCLUSIONS
Anti-TPO was present in one-third of pregnant women with type 1 diabetes and associated with slightly higher TSH, but not poorer glycemic control or adverse birth outcome. A total of 17% of women with type 1 diabetes were treated for thyroid disorder during pregnancy.
Vestgaard
Marianne
M
Center for Pregnant Women with Diabetes, Department of Endocrinology, Rigshospitalet, Faculty of Health Sciences, Copenhagen, Denmark.
Nielsen
Lene Ringholm
LR
Rasmussen
Ase Krogh
AK
Damm
Peter
P
Mathiesen
Elisabeth R
ER
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D001786:Blood Glucose / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000175:diagnosis; D007453:Iodide Peroxidase / Q000276:immunology*; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood / Q000276:immunology*; D011446:Prospective Studies; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D055815:Young Adult
D001323:Autoantibodies; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007453:Iodide Peroxidase; D013972:Thyrotropin; D013974:Thyroxine