Vaginitis, also known as vulvovaginitis, is inflammation of the vagina and vulva. Symptoms may include itching, burning, pain, discharge, and a bad smell. Certain types of vaginitis may result in complications during pregnancy. The three main causes are infections, specifically bacterial vaginosis, vaginal yeast infection, and trichomoniasis. Other causes include allergies to substances such as spermicides or soaps or as a result of low estrogen levels during breast-feeding or after menopause. More than one cause may exist at a time. The common causes vary by age. Diagnosis generally include examination, measuring the pH, and culturing the discharge. Other causes of symptoms such as inflammation of the cervix, pelvic inflammatory disease, cancer, foreign bodies, and skin conditions should be ruled out. Treatment depends on the underlying cause. Infections should be treated. Sitz baths may help with symptoms. Soaps and feminine hygiene products such as sprays should not be used. About a third of women have vaginitis at some point in time. Women of reproductive age are most often affected. A woman may have vaginal itching or burning and may notice a discharge. The discharge may be excessive in amounts or abnormal in color (such as yellow, gray, or green). The following symptoms may indicate the presence of infection: Vaginal infections left untreated can lead to further complications, especially for the pregnant woman. For bacterial vaginosis, these include 'premature delivery, postpartum infections, clinically apparent and subclinical pelvic inflammatory disease, postsurgical complications (after abortion, hysterectomy, caesarian section), increased vulnerability to HIV infection and, possibly, infertility'. Studies have also linked trichomoniasis with increased likelihood of acquiring HIV; theories include that 'vaginitis increases the number of immune cells at the site of infection, and HIV then infects those immune cells.' Other theories suggest that trichomoniasis increases the amount of HIV genital shedding, thereby increasing the risk of transmission to sexual partners. While the exact association between trichomoniasis infection and HIV genital shedding has not been consistently demonstrated, 'there is good evidence that TV treatment reduces HIV genital shedding. Five studies were reported in the literature and, of these, four found a decrease in HIV genital shedding after TV treatment.'