Rationale: The active ingredient in most spermicide products, nonoxynol-9 (N-9), is absorbed in small quantities from the vagina during use. No adverse systemic effects from N-9 have ever been shown in women. One study found that users of spermicide products containing nonoxynol-9 or octoxynol had a higher risk of congenital malformations in pregnancies conceived during use than did nonusers. But several subsequent studies on spermicide use and birth defects have not shown any association, and researchers do not believe that spermicide use has any adverse effects on the fetus (70, 133, 251).

Rationale: The active ingredients of most spermicide products are surfactants that disrupt cell membranes of spermatozoa, pathogens, and genital epithelium. In one study of frequent N-9 insertion, erythema and microscopic epithelial lesions were equally frequent among women inserting N-9 every other day as among placebo users. The rate of irritation was twice as high among women inserting N-9 once or twice daily, and 5 times higher among women inserting four N-9 suppositories daily than among placebo users. Similar findings have been reported in a WHO-sponsored study of the spermicide menfegol (100, 227).

Experts fear that the epithelial lesions of spermicide-associated irritation may increase the risk of contracting HIV infection if exposure to HIV occurs. This has not been demonstrated in a human study, but it is plausible, and local irritation should be avoided.

Recommendation: Discomfort with spermicide use is uncommon when used at typical family planning frequencies of once per day or less. If discomfort is reported, a different spermicide product with different ingredients may solve the problem. If discomfort persists, a different contraceptive method is indicated.

Rationale: In studies of spermicide use (approximately one to two times per day) for family planning purposes, roughly 5% to 10% of women have symptoms of discomfort after use. The clinical significance of discomfort is unclear because discomfort is a self-perceived problem, and it may not be correlated with signs of vaginal or cervical irritation detected during examination (80, 227).

Recommendation: A woman should insert a new dose of her spermicide product before each act of intercourse. Furthermore, a woman should insert a new dose of spermicide if intercourse takes place an hour or more after initial insertion.

Rationale: In order to be effective, the spermicide must be high in the vagina near the cervix, with a sufficient concentration of the active ingredient. Due to different delivery formulations, some products leak down toward the vulva more quickly than others; some spread better than others. Manufacturers of suppositories, gels, and film generally claim that their product is effective for up to 1 hour after insertion, but the period of effectiveness might be longer. Since spermicides are typically less effective in preventing pregnancy than other methods, it is prudent to insert a new dose for each intercourse (114).

Rationale: The failure rates of spermicides in the first year of use range from 6% with perfect use to 21% with typical use. These rates are similar to those for the diaphragm and female condom (276).

However, for sexually active women who cannot use male or female condoms, a spermicide product may be preferable to unprotected intercourse, unless there are multiple acts of intercourse per day.

Rationale: Little research has been done on spermicide use and HIV risk, and the findings of the only two published studies conflict. In one study, nonoxynol-9 contraceptive sponge users had a higher incidence of HIV infection. In the second study, N-9 suppository users had a lower incidence of HIV. Until large randomized studies currently under way can resolve the controversy, spermicide alone cannot currently be recommended for HIV prevention.

Theoretically, spermicides may reduce the incidence of HIV indirectly by preventing bacterial STD cofactors. Spermicides have also been shown to have direct effects on HIV in vitro (80, 81, 132, 155, 220, 281).

The highest risk of sexually acquired HIV infection is associated with unprotected intercourse. Women need methods to protect themselves against HIV and other STDs, even if protection is only partial (71, 230).

The effectiveness of any coital-dependent method (i.e., one that must be applied at or around the time of intercourse) depends on the consistency and correctness of use. For these methods, acceptability and compliance are as important, if not more so, as their effectiveness during perfect use. Even if a female method is less efficacious than the male condom during perfect use, it may have a greater impact on disease rates if it is used more consistently. Consistent use of condom with spermicide may be more effective.

Rationale: Spermicides have been shown to provide protection against some bacterial STDs. Studies with different kinds of participants and different study designs have consistently demonstrated that spermicide use reduces the number of new gonorrheal and chlamydial infections. One study found an overall reduction in gonorrhea of about 50% in nonoxynol-9 users, but that figure includes both consistent and correct users as well as inconsistent users. A greater reduction was found among the most consistent users of the spermicide. Another study found a 25% reduction overall in nonoxynol-9 users. In studies that have compared bacterial STD risk among women relying on male condoms with those using a spermicidal method, the risks for infections were about the same. Most likely, the spermicides were used more consistently than were male condoms (180, 200, 229, 293).

Although some providers recommend that spermicide should not be used until 6 weeks after delivery or abortion and healing and uterine involution are complete, there is no evidence to support this practice.