Association between previously unknown connective tissue disease and subclinical hypothyroidism diagnosed during first trimester of pregnancy

Capsule:
Connective tissue diseases are associated to autoimmune thyroid disorders in pregnancy. Thyroid autoimmunity and antinuclear antibodies could have a detrimental effect on pregnancy outcomes.

Authors:
Fausta Beneventi, M.D., Elena Locatelli, M.D., Claudia Alpini, M.D., Elisabetta Lovati, M.D., Véronique Ramoni, M.D., Margherita Simonetta, M.D., Chiara Cavagnoli, M.D., Arsenio Spinillo, M.D.

Volume 104, Issue 5, Pages 1195-1201

Abstract:

Objective:
To investigate the presence of autoimmune rheumatic disorders among women with autoimmune thyroid disorders diagnosed during the first trimester of pregnancy and subsequent pregnancy outcomes.

Design:
Case-control study.

Setting:
Tertiary obstetric and gynecologic center.

Patient(s):
Pregnant women in the first trimester of pregnancy.

Intervention(s):
Clinical, laboratory, ultrasonographic evaluations.

Main Outcome Measure(s):
Thyroid-stimulating hormone (TSH) level; antibodies against thyroperoxidase, thyroid globulin and TSH receptor detection; screening for rheumatic symptoms and antinuclear antibodies (ANA); uterine artery pulsatility index evaluation; pregnancy complication onset.

Result(s):
Out of 3,450 women enrolled, 106 (3%) were diagnosed with autoimmune thyroid disorders. ANA were present in 18 (16.9%) of 106 cases and 26 (12.6%) of 206 controls. Of the cases, 28 (26.4%) of 106 reported rheumatic symptoms, 5 of these were diagnosed with Sjögren syndrome or with undefined connective tissue disease. Autoimmune thyroid diseases are statistically significantly associated with a higher risk of preeclampsia, fetal growth restriction, and overall pregnancy complications compared with controls, with a higher uterine artery pulsatility index, suggesting a defective placentation in thyroid disorders. The effect of ANA-positivity on moderate/severe adverse pregnancy outcomes was statistically significant among the patients with thyroid disorders (9 of 18 as compared to 8 of 88, odds ratio 9.65; 95% confidence interval, 2.613–7.81).

Conclusion(s):
Connective tissue diseases are frequently associated with autoimmune thyroid disorders diagnosed during the first trimester of pregnancy. Thyroid autoimmunity and ANA positivity independently increased the risk of adverse pregnancy outcomes.

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