Studies have shown that 2.3% of women with fertility problems were found to have had an over active thyroid (hyperthyroidism), compared with 1.5 percent of those in the general population. The condition is also linked with menstrual irregularity and result in reduced rates of conception, increased miscarriage risk and adverse pregnancy and neonatal outcomes.
http://www.webmd.com/infertility-and-reproduction/news/20150126/thyroid-trouble-may-harm-womens-fertility-study-finds