I remember a couple of Witnesses who kept this on the QT because they thought it would keep them from becoming elders. I also knew a sister who wouldn't get a tubal ligation because she felt it was "mutilation".
When she found out many sisters had had one for years, she just about freaked. One sad case I know was of a sister who refused a hysterectomy when she was diagnosed with advanced cervical cancer because she thought it was mutilation and would displease Jehovah.
She was told that we're not under the LAW, but decided her conscience wouldn't allow it "just in case". She had other treatment and is still alive, but not doing well.
Personally, I think she was just afraid of "losing her womanhood" as she put it and this was a convenient non-reasoning.