Impact of positive thyroid autoimmunity on pregnant women with subclinical hypothyroidism

Abstract

BackgroundThe impact of subclinical hypothyroidism (SH) and thyroid autoimmunity on obstetric and perinatal complications continues to be a matter of interest and highly controversial. AimTo assess the impact of SH and autoimmunity in early pregnancy on the obstetric and perinatal complications in our population. Material and methodA retrospective cohort study in 435 women with SH (TSH ranging from 3.86 and 10μIU/mL and normal FT4 values) in the first trimester of pregnancy. Epidemiological and clinical parameters were analyzed and were related to obstetric and perinatal complications based on the presence of autoimmunity (thyroid peroxidase antibodies [TPO]>34IU/mL). ResultsMean age was 31.3 years (SD 5.2). Seventeen percent of patients had positive TPO antibodies. Presence of positive autoimmunity was associated to a family history of hypothyroidism (p=0.04) and a higher chance of miscarriage (p=0.009). In the multivariate analysis, positive TPO antibodies were associated to a 10.25-fold higher risk of miscarriage. No statistically significant associations were found with all other obstetric and perinatal complications. ConclusionsIn our region, pregnant women with SH and thyroid autoimmunity had a higher risk of miscarriage but not of other obstetric and perinatal complications.