Noncomparative contraceptive efficacy of cellulose sulfate gel.

OBJECTIVE: To estimate the 6-month cumulative probability of pregnancy, short-term adverse effects, and acceptability of cellulose sulfate vaginal contraceptive gel. METHODS: Two hundred fertile heterosexual couples were enrolled in this single-center, phase II, 6-month noncomparative study conducted at the California Family Health Council in Los Angeles, California. Couples did not desire pregnancy, were at low risk for sexually transmitted diseases, and agreed to use 3.5 mL of cellulose sulfate gel intravaginally before each coital act as their primary means of contraception. Scheduled follow-up visits took place after one menstrual cycle and at study completion, which occurred after 6 months and six menstrual cycles had elapsed. In addition, participants were instructed to call the site at the onset of each menses to review their diary cards. RESULTS: The cumulative probabilities of pregnancy during 6 months and six cycles of typical use were 13.4% (95% confidence interval [CI] 7.5-19.4%) and 13.9% (95% CI 7.7-20.2%), respectively, and during 6 cycles of correct and consistent ("perfect") use: 3.9% (95% CI 0.0-9.2%). Slightly over one fourth of the women and one man reported experiencing gel-related adverse events, two thirds of which were mild and only possibly related to the gel. Three quarters of women and men reported that they would buy cellulose sulfate gel for contraception. CONCLUSION: Cellulose sulfate vaginal gel yields pregnancy rates comparable to nonoxynol-9 and few adverse events among couples at low risk for sexually transmitted diseases.

Effectiveness of the male latex condom: combined results for three popular condom brands used as controls in randomized clinical trials.

BACKGROUND: Although public health programs invest heavily in the male latex condom, its efficacy in preventing pregnancy and sexually transmitted disease has been based primarily on in vitro and retrospective studies. METHODS: We combine the results from two randomized, controlled contraceptive efficacy trials that used commercial latex condoms brands (Ramses Sensitol, LifeStyles, Trojan-Enz) in the control arms. Combining data from the two studies, we obtained longitudinal data covering 3526 menstrual cycles contributed by approximately 800 couples who used latex condoms exclusively for up to six menstrual cycles. Both trials also collected 3715 detailed breakage and slippage reports from the first five study condom uses. The second trial also tested 243 postcoital vaginal samples collected after the first study condom use for the presence of prostate-specific antigen (PSA) and spermatazoa. RESULTS: The combined clinical breakage rate for the first five condom uses was 0.4% for the three latex brands and the combined clinical slippage rate was 1.1%. The combined six-cycle typical-use pregnancy rate for the latex condoms was 7.0% (95% confidence interval 5.0-9.0). The combined six-cycle consistent-use pregnancy rate was 1.0% (95% confidence interval 0.0-2.1). PSA was detected in only 1.2% of postcoital vaginal samples collected after the first use of an intact study condom. There were no differences in performance or efficacy among the three latex brands tested. CONCLUSIONS: The male latex condoms rarely broke or slipped off during intercourse and provided high contraceptive efficacy, especially when used consistently. Risk of semen leakage from intact condoms was very low.

Evaluation of the efficacy of a nonlatex condom: results from a randomized, controlled clinical trial.

CONTEXT: To reduce unintended pregnancy and HIV infection, it is critical to develop reliable male condoms that will attract consumers who reject conventional latex condoms. METHODS: In a prospective clinical trial conducted in 1998-2000, 830 monogamous couples were randomized in equal numbers to use either a nonlatex condom or a commercial natural latex condom for six months as their only method of birth control. Couples completed detailed reports for the first five condom uses and recorded intercourse and condom use in coital diaries. Pregnancy rates associated with typical and consistent condom use were calculated using life-table analysis. Rates of clinical failure (condom breakage or slippage) were determined for the first five condom uses. RESULTS: During the first five uses, the nonlatex condom had a higher frequency of breakage or slippage during intercourse or withdrawal (4.0%) than latex condoms (1.3%); the breakage rate for the nonlatex condom was about eight times that of latex condoms. The six-cycle typical-use pregnancy rate did not differ significantly between users of nonlatex (10.8%) and latex condoms (6.4%). The six-cycle consistent-use pregnancy rate was higher for nonlatex condom users than for latex condom users (4.9% vs. 1.0%). CONCLUSIONS: The data present strong indirect support for public health messages that promote the use of latex condoms and, for individuals who cannot or are unwilling to use latex condoms, the use of nonlatex condoms for prevention of pregnancy and disease.

Use of prostate-specific antigen (PSA) to measure semen exposure resulting from male condom failures: implications for contraceptive efficacy and the prevention of sexually transmitted disease.

Accurate measurement of semen exposure resulting from condom failures can refine public health messages and improve predictions of condom efficacy in preventing pregnancy and HIV transmission. Eight hundred and thirty couples enrolled in a condom efficacy study were asked to collect a baseline sample of ejaculate from the inside of the first study condom they used and to collect a postcoital vaginal sample whenever a study condom broke or slipped off during intercourse. All samples were quantitatively tested for prostate-specific antigen (PSA), a substance found only in human semen, using rocket immunoelectrophoresis, and inspected microscopically for presence of sperm. Sixty-eight baseline ejaculate samples collected from the inside of the first study condom by couples who subsequently experienced a condom failure averaged 13.4 microg PSA per swab and 79% of the samples averaged one or more sperm per high power field (hpf). Seventy-nine postcoital vaginal samples obtained after a condom break averaged 5.7 microg PSA per swab and only 38% averaged one or more sperm per hpf. The PSA results indicated a 50% reduction in semen exposure compared to baseline levels (p = 0.0001). Seventeen samples obtained after a condom slip-off averaged 2.5 microg PSA per swab and none of the samples averaged one or more sperm per hpf. The PSA results indicated an 80% reduction in semen exposure compared to baseline levels (p = 0.0001). Our results suggest that even condoms that fail reduce the risk of pregnancy and the transmission of sexually transmitted disease compared to unprotected intercourse. We also used PSA results to adjust a model designed to predict consistent-use pregnancy rates from condom breakage and slippage data.