Spermicide used alone for contraception.

Area of Science:

• Reproductive Health
• Contraception Research
• Clinical Trials

Background:

• Spermicides, used for millennia as contraceptives, are vaginal medications containing active ingredients like nonoxynol-9 dispersed in various formulations.
• Recent research has focused on comparative efficacy and acceptability of spermicidal products.

Purpose of the Study:

• To systematically review all randomized controlled trials (RCTs) evaluating spermicides used as standalone contraceptives.
• To assess the efficacy and identify factors influencing pregnancy rates in spermicide users.

Main Methods:

• Comprehensive search of multiple databases (CENTRAL, MEDLINE, POPLINE, etc.) for RCTs of spermicides used alone.
• Inclusion criteria required commercial products and sufficient data for pregnancy rate determination.
• Descriptive analysis of extracted data due to high participant dropout rates and lack of meta-analysis.

Main Results:

• Fourteen trials were identified, with no new trials since the initial review.
• The largest trial indicated a lower-dose nonoxynol-9 gel (52.5 mg) was less effective than higher doses (100 mg, 150 mg).
• Pregnancy probabilities at six months varied significantly by dose, but trial validity was limited by high discontinuation (39%).

Conclusions:

• Pregnancy probability in spermicide trials shows wide variation, with lower-dose nonoxynol-9 gels demonstrating inferior efficacy.
• User characteristics and behavior appear more critical than product specifics in determining contraceptive outcomes.
• High dropout rates in spermicide trials pose significant challenges to validity and recruitment.