Barrier and Other Pericoital Contraceptives

Vaginal foams, creams, and suppositories contain agents that provide a chemical barrier to sperm by damaging sperm cell membranes and thus preventing fertilization. Most spermicides contain nonoxynol-9 and are available without a prescription. These products are similar in efficacy; overall, the pregnancy rate is 19% with perfect use and 28% with typical (ie, inconsistent) use.

Spermicides should be placed in the vagina at least 10 to 30 minutes and no more than 1 hour before sexual intercourse and reapplied before each coital act.

Because their efficacy is limited, spermicides are often used with other barrier methods. Spermicides do not reliably protect against sexually transmitted infections (STIs). Also, spermicidal agents may cause vaginal irritation that increases the risk of HIV transmission. For this reason, condoms are no longer lubricated with nonoxynol-9.

Vaginal gel changes the vaginal pH; this change incapacitates sperm and thus prevents fertilization. Vaginal gel contains primarily lactic and citric acids. The pregnancy rate is 7% with perfect use and 14% with typical use. Using other barrier methods with vaginal gel improves efficacy.

Vaginal gel should be placed in the vagina no more than 1 hour before sexual intercourse and reapplied before each coital act.

Vaginal gel does not reliably protect against sexually transmitted infections.

Condom use reliably reduces the risk of STIs, including HIV infection. Condoms may be made of latex, polyisoprene, polyurethane, silicone rubber, or lamb intestine. Lamb-intestine condoms are impenetrable to sperm but not to many of the viruses that can cause serious infections (eg, HIV). Thus, latex and synthetic (polyurethane, polyisoprene, and silicone rubber) condoms are preferred. Condoms also protect against human papillomavirus (HPV), thus reducing the risk of precancerous cervical lesions.

The male condom is the only reversible male contraceptive method other than withdrawal, which has higher contraceptive failure rates.

The male condom is applied before penetration; the tip is pinched shut and should extend about 1 cm beyond the penis to collect the ejaculate.

The female condom is a pouch with an inner and an outer ring; the inner ring is inserted into the vagina, and the outer ring remains outside and covers the perineum. The female condom should be placed no more than 8 hours before intercourse. The penis should be carefully guided through the external ring to make sure that the ejaculate is collected in the pouch.

For both types of condoms, care must be taken to avoid spilling condom contents when the penis is removed after intercourse. With the male condom, the penis should be withdrawn immediately after ejaculation while the condom’s rim is held firmly against the base of the penis; this precaution prevents the condom from slipping off and spilling semen. The larger ring of the female condom should be twisted to prevent semen from spilling. Emergency contraception Emergency Contraception Commonly used emergency contraception regimens include Insertion of a copper-bearing T380A IUD within 5 days of unprotected intercourse Insertion of a 52-mg levonorgestrel-releasing IUD, which... read more should be used if contents spill, the condom slips, or the condom breaks.

A new condom should be used for each coital act.

Pregnancy rates at 1 year are

The diaphragm is a dome-shaped cup with a flexible rim that fits over the cervix and upper part and lateral wall of the vagina. They are used with a spermicide and, together, provide an effective barrier to sperm. Spermicide is applied to the diaphragm before insertion. After the first coital act, additional spermicide should be inserted into the vagina before each subsequent act. Diaphragms can be washed and reused.

Conventional latex diaphragms are made in various sizes. They are fitted in a woman by a health care practitioner so that it is comfortable for her. After childbirth or a significant weight change, conventional diaphragms need to be refitted.

A new single-size diaphragm (single-size contraceptive barrier device, or SILCS diaphragm) is made of silicone and considered to be one size fits most. It is softer and more durable than traditional latex diaphragms.

The diaphragm should remain in place for at least 6 to 8 hours but not more than 24 hours after intercourse.

Pregnancy rates with conventional latex diaphragms in the first year are about 6% with perfect use but about 12% with typical use. Pregnancy rates with the SILCS diaphragm are similar to conventional diaphragm (1 Diaphragm reference Barrier contraceptives include vaginal spermicides (foams, creams, gels, suppositories), contraceptive gel, condoms, diaphragms, cervical caps, and contraceptive sponges. Vaginal foams, creams... read more ).

Diaphragms were once widely used (one third of women in 1940), but by the 2000s, fewer than 1% of women in the US were using them. This decline in use is largely due to the development of many other more effective and easy-to-use contraceptive methods.

The cervical cap is made of silicone and resembles the diaphragm but is smaller and more rigid.

A spermicidal cream or gel should always be used with a cervical cap. The cervical cap must be inserted before intercourse; it should remain in place for at least 6 hours after intercourse and not more than 48 hours.

Pregnancy rates are 18% with typical use in the first year, 10 to 13% with perfect use; rates are higher among parous women because obtaining a secure fit after childbirth is difficult.

Only one cervical cap is available in the US. It comes in 3 sizes (small, medium, large); size is chosen based on a woman's pregnancy history. A health care practitioner must write a prescription before the cervical cap can be used, but it does not require a custom fitting.

The contraceptive sponge acts as both a barrier device and a spermicidal agent. It can be inserted up to 24 hours before intercourse. It should be left in place for at least 6 hours after intercourse. Maximum wear time should not exceed 30 hours.

Pregnancy rates with typical use are 12% for nulliparous women and 24% for parous women.