Effectiveness of BenZalkonium Chloride Gel as Vaginal Contraceptive: a Multicentric Randomized Controlled Trial

Inclusion Criteria: * at risk for pregnancy and desiring contraception * having regular menstrual cycle (21-35 days) * at low risk for HIV or other sexually transmitted infection * sexually active * use the test products as their primary method of contraception * keep a diary of coital activity, product use, and adverse events Exclusion Criteria: * diagnosis of any vaginal infection or any symptom of STDs at baseline * known allergy or hypersensitivity to N-9 or BZK * menopause for more than one month * breastfeeding * vaginal bleeding with unknown reasons * genitourinary system anomaly * hysteroptosis II or severe cystocele * moderate to severe erosion of cervix * malignant reproductive system tumors