Hives After Stopping Birth Control

My wife first started getting hives after having our first child. She went to many doctors who could not determine the cause. She eventually got Mirena and the hives went away. We weren't sure if the Mirena stopped them or if it was just coincidence. Well, now we want to have a second child, so she got her Mirena out. The hives have returned, which leads us to believe that there really is something in the birth control stopping the hives. Our question is, is there a medication or hormones that a woman can take that will prevent the hives and still allow us to keep trying to have a baby? We're both really worried that it's going to have to be one way or the other. Thank you for your time and consideration.

Thanks, Red. Would appreciate that link if you find it. Anything feels helpful at this point.

My wife went to the doctor a lot before putting the Mirena in and they put her through a lot of allergy and thyroid tests that never really found anything. We've tried all sorts of otc medications and recommended vitamins/supplements to no avail. The only thing that we've confirmed to work is the Mirena, which leads us to the hormones route.