Effect Of Autoimmune Thyroiditis On The Outcomes Of In Vitro Fertilization And Embryo Transfer

Background:Autoimmune thyroiditis is one of the most common autoimmune diseases and also the most frequent cause of hypothyroidism in women of reproductive age. In infertile women, the prevalence of those positive for anti-thyroid antibodies is higher than their fertile control. Autoimmune thyroiditis is associated with increased risk of recurrent spontaneous abortion and repeated implantation failure.Objective:This study aims to investigate the effect of autoimmune thyroiditis on outcomes of in vitro fertilization and whether levothyroxine (LT4) treatment may improve the situation.Methods:A retrospective analysis was undertaken in infertile euthyroid women with tubal factors, who underwent their first assisted reproduction technology procedure in the affiliated Women’s Hospital of Zhejiang University between August 1st 2013 and April 1st 2015.481 patients were included. Those positive for ATA were divided into two groups:1) 221 patients without LT4 treatment; 2) 31 patients with LT4 treatment. 229 consecutive ATA-negative patients whose age and BMI matched those of ATA-positive patients were included as control.Number of oocytes retrieved, fertilization rate, high-grate embryo rate, biochemical pregnancy rate, pregnancy rate, abortion rate, ectopic pregnancy rate, live birth rate, preterm birth rate, birth rate of offspring were compared between groups.Results:ATA-positive patients with LT4 treatment had significantly lower TSH level(1.1±0.7IU/mL) compared with ATA-positive untreated patients (1.6±0.5IU/mL) and control (1.5±0.5IU/mL). The fertilization rate of ATA-positive patients with LT4, ATA-positive untreated patients and and control were 53.0%,56.0% and 60.1% respectively. ATA-positive groups had significantly lower fertilization rates than control (P<0.05). The implantation rate of ATA-positive untreated patients and ATA-positive patients with LT4 were 31.8% and 30.0% respectively, both significantly lower than control (58.2%, P<0.05). Basal FSH was correlated with fertilization rate (r=0.090,P=0.049). The biochemical pregnancy rate of ATA-positive patients with LT4 was significantly higher than ATA-positive untreated patients and control. ATA-positive untreated patients had a significantly higher abortion rate than control (8.4% VS 2.5%, P<0.05). Birth weight of term birth offsprings was significantly lower in ATA-positive untreated patients than control (P<0.05). No difference in number of oocytes retrieved, high-grate embryo rate, pregnancy rate, live birth rate, preterm birth rate and ectopic pregnancy rate were observed between groups.Conclusion:ATA decreases fertilization rate and basal FSH may be associated with fertilization rate. ATA increases biochemical rate and abortion rate and decreases implantation rate. ATA increases the risk of lower birth weight of offsprings. Pregnancy rate and live birth rate are not affected by ATA.