Rationale: Two studies of a Nonspermicidal Fit-Free Diaphragm (60 mm) have been done. The first report, an analysis of past diaphragm use, found the Pearl pregnancy rate to be 1 per 100 woman-years. In the second, a prospective nonrandomized trial, the 12-month life-table pregnancy rate was 24.1 per 100 women, and the high failure rate led to early termination of the study. The effectiveness of this modified approach to diaphragm use has not been confirmed (256, 266).

Rationale: Until one-size-fits-all caps are available, fitting caps to each client is recommended. New cervical barrier devices have been devised, at least one of which is one-size-fits-all, and human use studies are under way (124, 186).

Rationale: Since the diaphragm comes in sizes from 50 mm to 105 mm in different models, almost all vaginas can be accommodated. The size and muscle tone of the upper vagina can change after pregnancy, however, so a new device may be needed.

It is unclear whether the effectiveness of the diaphragm varies according to parity. In one large study, parous women had a lower pregnancy rate than nulliparous women; in another, the rate among parous women was higher than that in nulliparous women. Parous women do not need to be advised that they are at higher risk of pregnancy (114, 278).

Rationale: The cervical cap comes in four sizes: 22, 25, 28, and 31 mm. Most women can be fitted properly, but perhaps 10% of prospective users cannot be fit and must use a different method.

In a large clinical trial, the pregnancy rate was substantially higher among parous women than nulliparous women for both typical and perfect use (114, 240, 278).

If intercourse occurs prior to 6 weeks, the use of another appropriate method (i.e., condom) should be recommended.

Rationale: The shape of the cervix, the size of the vaginal vault, and/or vaginal muscle tone may change after pregnancy and delivery or after second-trimester abortion. It takes 4 to 6 weeks for the uterine involution to be complete, and bleeding/spotting can continue for up to 8 weeks as well (cap use is contraindicated during bleeding).

Additionally, there is marked weight loss after delivery, and many providers recommend refitting after a weight loss of more than 7 kg (114, 240, 296, 302).

Until better data on contraceptive effectiveness refute the conventional recommendations, users should be advised to add spermicide to fitted diaphragms.

Rationale: Two studies of nonfitted diaphragms without spermicide had conflicting results. Research on fitted diaphragm use without spermicide are also conflicting. In a retrospective review of patient records, women using fitted diaphragms continuously (removing them only to wash) without spermicide had a lower pregnancy rate than did women following the conventional instructions. In a randomized trial comparing fitted diaphragm use with versus without spermicide, the typical use and perfect use pregnancy rates were lower in the diaphragm with spermicide group, but the study was small, and the differences were not statistically significant.

Some providers believe that spermicide cost, messiness, and potential for irritation have resulted in poor compliance, and they recommend diaphragm use without spermicide in an effort to enhance acceptability. But another important attribute of the diaphragm is that diaphragms used with spermicide protect against cervical infections and that spermicide use may reduce the risk of HIV infection. If spermicide use is partly responsible for reducing the risk of STD infection in women using diaphragms, it would be a disservice to instruct women to omit spermicide (27, 33, 82, 227, 256, 266).

Upon removal, diaphragms should be washed (and dried prior to storing).

Rationale: Spermatozoa remain viable in the vagina for several hours, but the great majority of sperm cells that are capable of entering the cervix do so within 2 hours post-ejaculation. N-9 spermicide can retain its contraceptive effect for a longer time: more than a day inside a cervical cap and 12 hours inside a diaphragm. The optimum time that diaphragms and caps should remain in place has not been tested, and, in the absence of evidence to the contrary, the conventional 6-hour recommendation is a sensible compromise (114, 174, 175, 207).

Rationale: No research has been done to compare diaphragm users who insert more spermicide before a second episode of intercourse and those who do not. As noted, N-9 spermicide may retain its contraceptive effect for more than a day inside a cervical cap and for 12 hours inside a diaphragm, but the impact of multiple ejaculations on N-9 potency is not known. In the absence of concrete data, it is prudent to insert a new dose of spermicide for each intercourse (114, 174, 175).

Rationale: Most studies have found that diaphragm users develop UTI at a rate two to three times higher than nondiaphragm users. However, it is not understood why this is the case. Foreplay and intercourse seem to introduce E. coli bacteria into the vagina. The spermicide and probably the diaphragm itself encourage vaginal and urethral colonization of the E. coli.

Several approaches may solve the UTI problem. Urination just before and just after intercourse may offer some protection. Wearing the diaphragm for less time may help. A smaller device or a different rim style may relieve pressure on the urethra. Switching to a cervical cap may be an option that retains many of the same advantages as the diaphragm (89, 114, 118).

Recommendation: There is no evidence that the cervical cap increases the risk of UTI, although it may do so.

Rationale: Since there are relatively few cervical cap users, it is difficult to study side effects of cap use. Since the cervical cap shares with the diaphragm the feature of extended spermicide exposure, it is possible that cap use will increase the risk of UTI to a similar extent (118).

For sexually active women who cannot use male or female condoms, a diaphragm, cap with spermicide, or spermicide alone is unlikely to be riskier than completely unprotected intercourse and may help prevent upper reproductive tract infections.

Rationale: The effectiveness of the diaphragm and cap against HIV is not known. Much depends on the site of infection; if the portal of virus entry is the cervix, the diaphragm and cap should confer good protection. Until the effectiveness of N-9 spermicide is established, diaphragm or cap use with N-9 spermicide cannot be recommended for HIV prevention (264, 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, 81, 230).