Effectiveness of BufferGel as a Vaginal Contraceptive

Inclusion Criteria * General good health * Sexually active, at risk for pregnancy, and desiring contraception * Low-risk for HIV or STD infection * Single sexual partner who is at low-risk for HIV or STD infection for 6 months prior to study entry * Expect to have same sexual partner for duration of the study * Normal cyclic menses with a usual length of 21 to 35 days * Documented history of at least two spontaneous, normal menstrual cycles since delivery, abortion, or after discontinuing hormonal contraception/hormonal therapy * Willing to accept a risk of pregnancy * Willing to engage in an average of 1 to 2 acts of heterosexual vaginal intercourse per week for a period of 6 months * Willing to be fitted with a diaphragm and use the diaphragm with test product during all acts of heterosexual vaginal intercourse for the duration of the study * Willing to only use the test product with diaphragm as the sole method of contraception over the course of the study (with the exception of emergency contraceptive pills when indicated) * Capable of using the product and diaphragm properly * Willing to keep a diary to record coital information, product use information, information about the use of other vaginal products, and sign and symptom data for self and partner * Agree not to participate in any other clinical trials during the course of the study * Written informed consent to participate in the trial Participant's Sexual Partner Must Not Be/Have * Infertile * Treated for Chlamydia trachomatis or Neisseria gonorrhoeae in the 6 months prior to study entry * HIV infected * More than one sexual partner in the 4 months prior to study entry * Engaged in homosexual intercourse * Shared injection drug needles in the 6 months prior to study entry * Allergy or sensitivity to spermicides or products containing Nonoxynol 9 or latex Exclusion Criteria * Pregnant or desire to become pregnant during the course of the study * History of infertility or conditions that may lead to infertility * Allergy or sensitivity to spermicides or products containing Nonoxynol 9 or latex * History of toxic shock syndrome (TSS) * Two or more urinary tract infections (UTIs) in the 12 months prior to study entry * Current suspected or diagnosed urinary tract infection or vaginitis * Contraindications to pregnancy (medical condition or chronic use of medications contraindicated for pregnancy) * Treated with antibiotics for pelvic inflammatory disease (PID) without a subsequent intrauterine pregnancy * More than one sexual partner in the 4 months prior to study entry * Shared injection drug needles in the 6 months prior to study entry * HIV infected or suspected HIV infection * Genital herpes simplex virus (HSV) infection with the first occurrence (initial episode) within 3 months prior to study entry or have clinical evidence of HSV on exam * Sexually transmitted diseases (STDs) in the 3 months prior to study entry * Lactating or breastfeeding * Abnormal vaginal bleeding or spotting in the month prior to study entry * Lower abdominal or pelvic pain in the month prior to study entry * Abnormal finding on pelvic examination which, in the view of the study investigator, precludes participation in study * Vaginal or cervical irritation, including vaginal or cervical epithelial disruption, ulceration, bleeding, petechiae, sloughing, or areas of obvious erythema * Vaginal or cervical biopsy or surgery in the 3 months prior to study entry * Vaginal or systemic antibiotics, antivirals, or antifungals in the 14 days prior to study entry * Depo-Provera injection in the 10 months prior to study * Vaginal or cervical abnormality that would interfere with the proper placement and retention of test product and diaphragm * Abnormal Pap smear in the 12 months prior to study entry * Consume (on average) greater than 2 to 3 alcoholic beverages per day * Drug abuse (recreational, prescription, or OTC) in the 12 months prior to study entry * Investigational drug or device use in the month prior to study entry * Previously participated in or completed this study