Hello, thanks for your query. Preterax doesn t cause infertility. There are few reasons why you are not able to conceive. 1. Age is the first and fforemost. Unfortunately, the number of eggs in the ovaries are constant and keeps getting depleted from the time of menarche. At 52 years of age, the number of remaining eggs in the ovary is very very less that even with ivf it is difficult to harvest a good number. Age also compromises the quality of eggs which is very important for the success of ivf. 2. Blocked fallopian tube makes it almost impossible for pregnancy to happen in natural way. Its unfortunate that one of your tube is blocked and the other has been removed. 3. In such a scenario, your doctor might have offered embryo donation as an option which you may like to consider if you wish. 4. You must also be aware of the possible effects of pregnancy on your health and take caution if pregnancy happens. Hope this helps. Take care.