I don't have a reference but I believe that this is not an isolated MD. One
of our attending docs was talking about this a few weeks ago. He said that
women are much more prone to sports injuries in the last two weeks of their
cycle because of the effects of progesterone from the corpus luteum on their
ligaments. He quoted a statistic, I don't remember the numbers but it was
something like 3 out of five injuries in the last two weeks of the menstrual
cycle. He said that progesterone also affects the pelvic floor too during
this time. Many women who use diaphragms or other intravaginal contraceptives
notices that their cervixes change position slightly during various parts of
their cycle.
Whether the effect is serious enough to make her wean I don't know. If her
menstrual cycle has returned I kind've doubt it. If she is worried about it,
maybe she should just postpone the surgery.