Barrier Contraceptives and Spermicides Key Points

• Barrier contraceptives and spermicides create a physical barrier to fertilization.

• Many of these methods are available over the counter, increasing access.

• Some barriers can provide protection against cervical infections; condoms also offer protection against HIV.

Mechanism of Action

Barrier contraceptives provide a physical barrier that prevents sperm from accessing the upper reproductive tract. They are often used in conjunction with spermicides, which act to destroy sperm and prevent fertilization.

Male Condom

Materials

Male condoms have been used since ancient times, with early condoms made from animal intestine. Mass production began in the 1840s with the advent of vulcanized

Table 26-3 Failure Rates for Contraceptive Methods: Percentage of Women who Become Pregnant during First Year of Use

Contraceptive method

Women pregnant in first year

Perfect Use (%)

Typical Use (%)

No method

85

85

Barrier contraceptives and spermicides

Male condom

2

15

Female condom

5

21

Cervical cap, nulliparous

9

16

Cervical cap, parous

26

32

Diaphragm

6

16

Contraceptive sponge, nulliparous

9

16

Contraceptive sponge, parous

20

32

Nonoxynol-9

18

29

Fertility awareness methods

Standard Days

4.75

12

TwoDay

3.5

14

Symptomothermal

2

Postovulation

1

Lactational amenorrhea

0.45

2.45

Coitus interruptus/withdrawal

4

27

Combined hormonal contraceptives

Combined oral contraceptives (OCs)

0.3

8

Contraceptive patch

0.3

8

Vaginal contraceptive ring

0.3

8

Progestin-Only contraceptives

Progestin-only pills (POPs)

0.3

8

Depot medroxyprogesterone acetate

0.3

3

Contraceptive Implant

0

0.1

Intrauterine contraceptives

Copper-T380A

0.6

0.8

Levonorgestrel intrauterine system

0.1

0.1

Sterilization

Tubal ligation

0.5

0.5

Essure

0

<1

Vasectomy

0.10

0.15

Data from Arevelo et al., 2002, 2004; Harrison-Woolrych and Hill, 2005; Palmer and Greenberg, 2009; Perez et al., 1992; Trussel, 2004; and van der Wijden et al., 2003.

Data from Arevelo et al., 2002, 2004; Harrison-Woolrych and Hill, 2005; Palmer and Greenberg, 2009; Perez et al., 1992; Trussel, 2004; and van der Wijden et al., 2003.

rubber. Modern condoms are most often made of latex or polyurethane, but those made from animal intestine do still exist. Polyurethane condoms provide increased sensitivity for male partners, but the breakage and slippage rates are significantly higher (relative risk, 6.6 for breakage and 6.0 for slippage) compared with latex condoms (Frezieres et al., 1998) (Level of evidence: A). This suggests that latex condoms should be encouraged except for those with latex allergy/sensitivity.

Advantages

Male condoms can decrease the transmission of STIs, including human immunodeficiency virus (HIV), when used correctly and consistently.

Disadvantages

To obtain maximum protection from pregnancy and STIs, condoms must be used correctly with every act of intercourse. Those individuals with an allergy or sensitivity to latex should avoid these condoms. Some men report decreased sensitivity with condom use. A new condom must be used for each act of intercourse.

Female Condom

The female condom is a thin polyurethane sheath with a ring on each end. It can be inserted into the vagina up to 8 hours before intercourse. It should not be used simultaneously with a male condom because of possible breakage or slippage of either device.

Advantages

Female condoms can decrease the transmission of STIs, including HIV, when used correctly and consistently. Many women prefer having direct control over a barrier device. The female condom can be placed in advance of intercourse, increasing spontaneity.

Disadvantages

To obtain maximum protection from pregnancy and STIs, condoms must be used correctly with every act of intercourse. Some women may experience vaginal irritation. A new condom must be used for each act of intercourse.

Cervical Cap and Diaphragm

Diaphragms are dome-shaped devices made from silicone or latex. Diaphragms come in a range of sizes and require a fitting and prescription from a health care provider. Diaphragms are used in conjunction with spermicide, can be placed in the vagina up to 6 hours before intercourse, and should be left in place for at least 6 hours after the last act of intercourse, but no longer than 24 hours. Subsequent acts of intercourse require insertion of additional spermicide without device removal.

A silicone cervical cap (FemCap) was approved by the U.S. Food and Drug Administration (FDA) in 2003. It is reusable, and the design includes a domed cap that completely covers the cervix and a brim that forms a seal against the vaginal wall, funneling the ejaculate into a groove between the dome and the brim that faces the vaginal opening, storing the spermicide and trapping sperm. It comes in three sizes: for nulliparas, for women who have been pregnant but did not deliver vaginally, and for women who have delivered a full-term infant vaginally. It requires a fitting and prescription from a health care provider. The cervical cap is used in conjunction with spermicide and should be left in place for at least 6 hours after the last act of intercourse, but no longer than 48 hours. Subsequent acts of intercourse require insertion of additional spermicide without device removal.

Advantages

Many women prefer having direct control over a barrier device. Diaphragms and cervical caps can be placed in advance of intercourse, increasing spontaneity. These methods may offer some protection against cervical infections and pelvic inflammatory disease (PID) but offer no protection against HIV.

Disadvantages

Diaphragms and cervical caps should be used in conjunction with spermicide, which may cause irritation in some individuals. Those individuals with an allergy or sensitivity to latex should avoid those diaphragms. The incidence of urinary tract infections (UTIs) may increase.

Contraceptive Sponge

The Today sponge was reintroduced to the U.S. market in 2005. It is a polyurethane sponge that contains 1 g of non-oxynol-9 spermicide. There is a dimple on one side that fits over the cervix and a loop on the opposite side to aid in removal. It is available over the counter (OTC) and is effective for up to 24 hours, regardless of the number of times intercourse takes place. It should be left in place for at least 6 hours after intercourse, but no longer than 30 hours. Each sponge can be used only once.

Advantages

Many women prefer having direct control over a barrier device. The contraceptive sponge may offer some protection against cervical infections and PID but offer no protection against HIV.

Disadvantages

Some individuals may experience sensitivity to the spermi-cide. Some women may experience vaginal dryness or an increased incidence of yeast infections, particularly if the sponge is left in place for longer periods.

Spermicides

Mechanism of Action

Nonoxynol-9 is a nonionic detergent that disrupts the membranes of epithelial cells, bacteria, and viruses. It reduces sperm motility and reduces nourishment by disrupting fruc-tolytic activity. It is available OTC in many forms, including gels, foams, and film. Although shown to inactivate many sexually transmitted pathogens in vitro, in actual use, nonoxynol-9 does not reduce rates of HIV, gonorrhea, or chlamydial infections when used with latex condoms (Roddy et al., 1998) (Level A).

Advantages

Many women prefer having direct control over contraception. Spermicides may be placed in advance of intercourse, increasing spontaneity, and can be used with barrier devices to increase efficacy.

Disadvantages

Some individuals may experience sensitivity to spermicide. Fresh spermicide should be placed with each act of intercourse.

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