Thyroid peroxidase autoantibodies predict poor metabolic control and need for thyroid treatment in pregnant IDDM women.
OBJECTIVE
To study whether the presence of antithyroid peroxidase antibodies (TPO-Abs) before gestation in IDDM affects thyroid function and metabolic control during pregnancy and early postpartum as well as neonatal outcome.


METHODS
A prospective study at an outpatient endocrine-obstetric unit was carried out in 20 pregnant IDDM women. Free T4 (thyroxine), thyroid-stimulating hormone (TSH), TPO-Abs, and HbA1c were assayed before gestation; during the first, second, and third trimester of pregnancy; and 3 months postpartum.


RESULTS
HbA1c was significantly higher in TPO-Ab+ women than in those who were TPO-Ab- during the second (P < 0.01) and third (P < 0.05) trimesters. HbA1c levels significantly decreased in TPO-Ab- patients when the second (P < 0.01) and third (P < 0.05) trimesters were compared with before the pregnancy and the first trimester. There was a significant increase in the dosage of insulin for TPO-Ab+ versus TPO-Ab- patients during the second (P < 0.05) and third (P < 0.01) trimesters and 3 months postpartum (P < 0.05). TSH was significantly increased in the second (P < 0.001) and third (P < 0.05) trimesters and 3 months postpartum (P < 0.01) when compared with TPO-Ab- patients; 7.6% of the TPO-Ab- group and 29% in the TPO-Ab+ group presented postpartum thyroid dysfunction, and 42% of the TPO-Ab+ women required thyroid treatment.


CONCLUSIONS
Pregnant women with IDDM who have a positive test for TPO-Abs before gestation have poorer glucose control and a high prevalence of hypothyroidism. Therefore we recommend that prepregnant IDDM patients be screened for anti-TPO-Abs. Those with a positive result should be followed with serial monitoring of free T4 and TSH levels during each trimester as well as the postpartum period.
Fernandez-Soto
L
L
Department of Medicine, University Hospital, Granada, Spain. amalia@goliat.ugr.es
Gonzalez
A
A
Lobón
J A
JA
Lopez
J A
JA
Peterson
C M
CM
Escobar-Jiménez
F
F
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D001786:Blood Glucose / Q000378:metabolism; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007037:Hypothyroidism / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D007453:Iodide Peroxidase / Q000276:immunology*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D011379:Prognosis; D011446:Prospective Studies; D011644:Puerperal Disorders / Q000097:blood / Q000188:drug therapy; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use*
D001323:Autoantibodies; D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007453:Iodide Peroxidase; D013972:Thyrotropin; D013974:Thyroxine