Updates in Contraception From The XVI World Congress of the International Federation of Gynecology and Obstetrics

David A. Grimes, MD

Disclosures

September 20, 2000

In This Article

New Alternative to Latex Condoms

Latex condoms, long a mainstay of contraception and STD prevention, have important limitations. From a medical perspective, the growing prevalence of allergy to latex, particularly among those with occupational exposure to this rubber, is worrisome. Indeed, skin contact with latex gloves has precipitated full-blown anaphylaxis.[1] A more common complaint is that the latex condom decreases sexual pleasure for 1 or both partners, and some find the smell of latex objectionable. In response, manufacturers have tried new twists such as textured and flavored condoms.

A fundamentally different approach, however, is to develop alternative materials for condoms. Lynley Cook, MD, and her colleagues[2] at Family Health International reported a randomized controlled trial of a new condom made of polyurethane film. In addition to its plastic material, the eZ-on condom, as its name implies, features a novel donning technique: it is baggy and unrolls in either direction. By contrast, traditional condoms unroll in only 1 direction, and the direction can sometimes be difficult to determine without adequate lighting.

In a rigorous, randomized, controlled crossover trial of clinical acceptability, Cook and her colleagues instructed 360 couples to use the eZ-on and latex condom (ie, each couple used each type in a predetermined sequence). For example, couples were randomized to the new condom for 4 consecutive acts of coitus, followed by the latex condom for 4, or the reverse sequence. A total of 345 couples had data available on 2624 uses of condoms in the study.

Overall, the eZ-on condom did not perform as well as the standard latex condom. The clinical breakage rate with the new condom was 6%, in contrast with 1% for the standard latex condom. Similarly, the slippage rate with the new condom was 2%, vs 1% with the latex condom. The overall "failure rate," which combines both breakage and slippage, was 7% for the new condom compared with 2% for the latex condom.

Adverse events were uncommon with both. These tended to be local reactions, such as genital irritation. None of the adverse events was serious. Similarly, no important medical complications occurred. Data on pregnancies were not reported; results of an effectiveness study are pending.

When asked about their preferences for the 2 condoms, couples were divided in their opinions. Similar proportions of both men and women favored each condom over the other. Although the clinical performance of the eZ-on appeared less satisfactory than that of the latex condom, nearly 30% of participants preferred the new condom to the standard condom. Hence, this new condom may have a niche to fill, for example, couples interested in condoms made of materials other than latex.

This randomized controlled trial is likely to have internal validity, that is, the ability to measure what it set out to measure. Randomized trials are the only known way to avoid selection bias, a common problem in trials of contraceptives. Because each couple used both types of condoms, each couple served as its own control. Thus, the observed differences are likely to be real and clinically important.

The question of external validity is not as clear. External validity is the ability to extrapolate from a study to the broader population of couples. Those who volunteered to take part in this trial are unlikely to be representative of the average couple using condoms: they probably were more interested in this method of contraception than most users. In addition, their compliance may have been unusually good. Hence, the ability to extrapolate from these volunteer couples to the broader community is unknown.

Other nonlatex condoms have been evaluated recently. These include the Avanti condom, also made from polyurethane. First marketed in the United States in 1994, the Avanti condom was so thin that it had unacceptable breakage rates. Other plastic condoms not made of polyurethane are in development.[3] However, whether plastic condoms will improve on the performance of standard latex condoms is unclear. When it comes to condoms, "new" may not be synonymous with "improved."

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