Maternal antithyroid antibodies and euploid miscarriage in women with recurrent early pregnancy loss

Objective: To determine whether an association exists between maternal antithyroid antibodies and euploid miscarriage in women with recurrent early pregnancy loss (REPL).

Design: Observational cohort study.

Setting: Two academic medical centers.

Patient(s): Women seen between 2004-2015 with a history of REPL, who were euthyroid or had subclinical hypothyroidism, had maternal antithyroid antibody testing and had at least one subsequent early pregnancy loss (<10 weeks' gestation).

Intervention(s): Thyroid function and antibodies were measured at consultation. Subsequent miscarriages were assessed by conventional cytogenetic analysis, and when indicated, microsatellite analysis and/or comparative genomic hybridization/single nucleotide polymorphisms were performed.

Main outcome measure(s): Determine whether maternal antithyroid antibodies are associated with euploid miscarriage.

Result(s): Cohort consisted of 74 subjects with REPL who had 130 subsequent early pregnancy losses. The prevalence of maternal antithyroid antibodies in the cohort was 17.6%. Mean TSH was significantly higher among subjects with maternal antithyroid antibodies. Otherwise, no significant differences in demographics were noted. When comparing types of early pregnancy losses between the two groups, a trend toward having more miscarriages than nonvisualized pregnancy losses was noted among subjects with maternal antithyroid antibodies (70% and 30%) compared with subjects without maternal antithyroid antibodies (55% and 43%). No significant difference was noted in the frequency of euploid miscarriage between subjects with and without maternal antithyroid antibodies (42% vs. 56%).

Conclusion(s): Our study did not demonstrate an association between euploid miscarriage and maternal antithyroid antibodies in subjects with a history of REPL. Therefore, testing or treatment in this cohort may not be warranted.