what causes vaginal discharge

Antibiotic or steroid use
Bacterial vaginosis, a bacterial infection more common in pregnant women or women who have multiple sexual partners
Birth control pills

Cervical cancer
Chlamydia or gonorrhea (STDs), sexually transmitted infections
Douches, scented soaps or lotions, bubble bath
Pelvic infection after surgery
Pelvic inflammatory disease (PID)
Trichomoniasis, a parasitic infection typically contracted and caused by having unprotected sex

Vaginal atrophy, the thinning and drying out of the vaginal walls during menopause
Vaginitis, irritation in or around the vagina
Yeast infections