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Pinkish or reddish vaginal discharge
in a case of hysterectomy
could be due to hypothyroidism, cervical dysplasia, cervical polyps, cervicitis (infection/inflammation of cervix), vaginitis (infection/inflammation of vagina), cervical cancer, hormonal imbalance as in polycystic disease of the ovary, use of blood thinners, genital ulcers, STDs and stress.
I would strongly recommend you to consult a gynecologist. It is difficult to comment beyond this at this stage.