system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why would a woman who has her tubes tied get an IUD?

I feel like I have a level of ignorance appropriate for a true ELI5 on this one! I am dating a woman who has told me that her tubes are tied. She recently had a bit of a scare with a mass on an ovary (which thankfully turned out ok). She mentioned that she is getting an IUD soon. Why would she be getting an IUD? We are both in our 40s.

(Note: When she mentioned the IUD I was confused and didn't ask why. I will do that the next time I see her but in the meantime I was curious.)

EDIT: Thanks folks, very enlightening!
gpt
Hormonal control.  Also, tube tying does have a failure rate and if they did a scan they may have seen something that gave them concerns regarding the continued efficacy of that form of birth control (some tube tying versions use clips, for instance.)