Hello, and i hope I can help you today. Unfortunately, having had a history of ectopic pregnancy is a risk factor for infertility as well as damage to the other remaining tube. However, thyroid disease can also affect ovulation and regular cycling of your period, so the treatment with the thyroid medication may help your chance of conceiving. However, I agree with your doctor s recommendation to check an HSG to determine if your one remaining fallopian tube is blocked. If you find out that your right tube is open, you certainly could conceive on your own. Many women with only one tube and ovary are able to get pregnant successfully. If it turns out that your right tube is blocked also, pregnancy can be achieved with in vitro fertilization which can be performed by a fertility specialist. So in summary- the results of the HSG test will be able to tell you definitely if you are able to conceive again. I hope I was able to adequately answer your question today and that this information was helpful. Best wishes, Dr. Brown