Preconceptional antithyroid peroxidase antibodies, but not thyroid-stimulating hormone, are associated with decreased live birth rates in infertile women

Objective: To study whether preconceptual thyroid-stimulating hormone (TSH) and antithyroid peroxidase (TPO) antibodies are associated with poor reproductive outcomes in infertile women.

Design: Secondary analysis of data from two multicenter, randomized, controlled trials conducted by the Reproductive Medicine Network of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Multivariable logistic regression analyses were performed to assess the association between preconceptual TSH levels and anti-TPO antibodies.

Setting: Not applicable.

Patient(s): Serum samples from 1,468 infertile women were utilized.

Intervention(s): None.

Main outcome measure(s): Cumulative conception, clinical pregnancy, miscarriage, and live birth rates were calculated.

Result(s): Conception, clinical pregnancy, miscarriage, and live birth rates did not differ between patients with TSH ≥2.5 mIU/L vs. TSH < 2.5 mIU/L. Women with anti-TPO antibodies had similar conception rates (33.3% vs. 36.3%) but higher miscarriage rates (43.9% vs. 25.3%) and lower live birth rates (17.1% vs. 25.4%) than those without anti-TPO antibodies. Adjusted, multivariable logistic regression models confirmed elevated odds of miscarriage (odds ratio 2.17, 95% confidence interval 1.12-4.22) and lower odds of live birth (oddr ratio 0.58, 95% confidence interval 0.35-0.96) in patients with anti-TPO antibodies.

Conclusion(s): In infertile women, preconceptional TSH ≥2.5 mIU/L is not associated with adverse reproductive outcomes; however, anti-TPO antibodies are associated with increased risk of miscarriage and decreased probability of live birth.

Clinical trial registration number: PPCOS II NCT00719186; AMIGOS NCT01044862.