Thyroid Autoimmunity and Intracytoplasmic Sperm Injection Outcome: A Systematic Review and Meta-Analysis

Background: Since 2010, three meta-analyses have been published on the impact of thyroid autoimmunity (TAI) on pregnancy outcomes in infertile women treated with assisted reproductive technology (ART). The initially observed high risk for miscarriage became very low in the most recent meta-analysis, published in 2016. Objective: To investigate whether the lower risk for miscarriage in the latest meta-analysis was associated with the increased use of intracytoplasmic sperm injection (ICSI) in recent studies. Data Source: MEDLINE was searched from January 1990 to May 2017. Study Selection: Data from case-control and cohort studies on ART (in vitro fertilization/ICSI) pregnancy outcomes in women with and without TAI. Only studies in which women were treated with ICSI were included. Data Extraction and Synthesis: Four studies were retained, including 1855 ICSI cycles (290 with and 1565 without TAI). In women with a clinical pregnancy (114 ICSI cycles with TAI and 651 without), there was no difference in miscarriage or live birth rates: respective combined odds ratios, 0.95 [95% confidence interval (CI), 0.48 to 1.87] and 1.12 (95% CI, 0.62 to 2.03), respectively. Age did not differ between women with and without TAI: combined mean difference of 0.13 years (95% CI, 20.51 to 0.76 years), but serum thyroid-stimulating hormone was higher in women with TAI: combined mean difference of 0.20 mIU/L (95% CI, 0.07 to 0.33 mIU/L). Conclusion: Infertile women with TAI treated with ICSI had no increased risk for a first-trimester miscarriage compared with women without TAI.