Diaphragm compared to diaphragm with spermicide for birth control

The diaphragm is an important type of birth control. The woman controls the method and it does not involve taking a drug. Also, the birth control can be reversed right away. The diaphragm is often used with a spermicide - a chemical to kill sperm. Many women feel that the spermicide is awkward and messy to use. Spermicides may increase the risk of infections in the urinary tract. Some health care workers think that spermicide does not help with birth control.

This review looked at trials of diaphragms used with and without spermicide. We looked at how well each method worked, how safe it was, and whether women liked using it.

We did computer searches for randomized trials that compared the diaphragm only to the diaphragm with spermicide. We also looked at reference lists to find trials. In addition, we wrote to researchers to find more studies.

We found one trial that looked at using the diaphragm with and without the spermicide. Of the women who used the diaphragm only, slightly more got pregnant than did those who used the diaphragm with spermicide. The study was too small to know how well the spermicide worked with the diaphragm for birth control. Large trials would help to address this issue. Current evidence gives no reason to change the practice of using spermicide with the diaphragm.

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.

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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 strategy: 

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.

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