I was told by my sister in law who is 42 that way back when she had her tubes tied it was exactly that and can be reversed not like today when the cut tie burn etc. And is not reverse able at all now days it is completely permanent. Congrats you must of been blessed for a reason :-)
Only abstinence and a full historectomy are 100% - I'm 38 weeks along and I had an IUD. Congrats and good luck!