Diaphragm versus diaphragm with spermicides for contraception

Abstract

Background: The diaphragm is usually used with a spermicide. However, some practitioners have suggested that spermicides offer no additional contraceptive protection and have advocated alternative guidelines for the use of diaphragms. Objectives: The objective of this review was to compare the effectiveness, safety and acceptability of the diaphragm with and without spermicide. Search methods: We searched MEDLINE, POPLINE, CENTRAL, LILACS and reference lists of relevant articles. We also searched for clinical trials in ClinicalTrials.gov and the International Clinical Trials Registry Platform (ICTRP). In addition, we contacted experts in the field to identify unpublished studies. Selection criteria: We included randomized controlled trials comparing women of reproductive age using the diaphragm with and without spermicide. The diaphragm had to be the sole contraceptive method, and the report had to include clinical outcomes. Data collection and analysis: Two authors independently extracted data on outcomes and trial characteristics. Any discrepancies were resolved by consensus or by consultation with a third author. The results of the one identified study are presented descriptively. Main results: We identified only one study. No significant difference was found in the pregnancy rates (with typical use or consistent use) or discontinuation rates between the diaphragm-with-spermicide and diaphragm-without-spermicide groups. A trend toward higher pregnancy rates was noted in the diaphragm-without-spermicide group. However, this study failed to recruit the planned number of participants and was consequently underpowered. Authors' conclusions: As only one underpowered study was identified, we cannot distinguish between the contraceptive effectiveness of the diaphragm with and without spermicide. We cannot draw any conclusion at this point. Randomized controlled trials with adequate numbers of participants would be required to adequately examine this issue. However, the study provides no evidence to change the commonly recommended practice of using the diaphragm with spermicide.