Syndol has a very small amount of codeine .I think just from my own personal fertility problems when I was trying to have kids .I would stop taking it will it make a difference or not I am not sure .Have you talked to your doctor and discussed your concerns about it and fertility.
That's something you should ask your prescribing physician. Syndol isn't a medication used in the US. I had to search for a while just to find out what was in it. From what I can tell it's simply Tylenol, Caffeine, Codeine and a sedating antihistamine similar to Benadryl. Just by looking at the profile, I'm assuming it's prescribed for tension headaches? If you're trying to conceive, you may want to just try not using it for a while. The amount of codeine in it may give you some minor withdrawals, but it should be OK in a few days.