My wife has not menstruated for many years and is about to have a thankfully non-malignant polyp removed from her womb. She asks whether this will put her in nidda and whether she will be required to bensch gomel. Thank you.
It will make her a niddah. This is because it is going to cause bleeding from the uterus, not only from getting into the uterus, but also from the removal of the polyp. This applies even though she didn’t see in a long time.
Regarding Hagomel, women don’t usually say hagomel, for reasons of tznius. Even though there are women who do say it after a birth, that is because the birth was something that everyone knows in any case.
Y:D 188-3 Noda B’yehuda 2-120, PIschei Teshuva 188-4, Shiurei Shevet Halevi pg 99, .
Regading Hagomel M:B 219-3, R’ Y. Cahen shlit”a