Barrier Methods of Contraception



Barrier Methods of Contraception


Jill Schwartz, MD, MPH



Barrier methods of contraception have been the most widely used contraceptive techniques throughout recorded history. Although barriers represent the oldest of contraceptive methods, our response to the personal and social impact of sexually transmitted infections (STIs) has placed new importance on these approaches for dual prevention of pregnancy and human immunodeficiency virus (HIV) and other STIs. Male and female condoms represent the first line of defense, and other multipurpose prevention technologies (MPT) strategies are now in development.

Physical barrier methods (e.g., condoms, diaphragm, and cervical cap) and chemical barriers (e.g., spermicides) have higher and more variable perfect-use failure (2% to 20%) than do other modern methods, and also show the largest difference between perfect use and typical use.1,2 For this reason, we classify these as the “least effective” contraceptive methods, along with withdrawal and fertility awareness-based methods (see Chapter 1, Figure 1.4). However, for many couples, a barrier may represent an appropriate choice despite higher perfect-use failure. The coital-dependent timing of use likely contributes to typical-use failure. For this reason, clinicians counseling women on use of barrier methods should stress correct and consistent use to bring users closer to perfect-use efficacy.

The importance of this counseling cannot be overemphasized. Many clinicians seem to give up on women who do not accept moderately or highly effective methods. Correct and consistent use of a less effective method will generally result in better outcomes than incorrect and inconsistent use of a more effective method. Obviously, long-acting reversible contraceptive (LARC) methods do not meet the needs of all couples, and women and their partners have differing tolerance for a contraceptive failure. For example, some women may prioritize a method that they control, and accept a higher risk of failure with a barrier method. In contrast, barrier methods represent a poor choice for women unable to accept the risk of contraceptive failure. The role of the clinician is to guide this discussion. In the past, primary care providers frequently recommended barrier methods to women with medical comorbidities that increase the risk of both pregnancy and hormonal contraception. For women with contraindications to pregnancy, best practice would involve directed counseling for medically appropriate LARC methods or permanent contraception.



Modern History of Barrier Methods


Modern physical barrier methods include male and female condoms, vaginal diaphragms, cervical caps, and vaginal sponges. Some of these methods are used in combination with a chemical barrier or spermicide. Early methods like the latex All-Flex diaphragm and the original cervical cap (“Prentif”) are no longer available. While a silicone diaphragm similar to the original diaphragm is still marketed, novel diaphragms and caps have been introduced to increase availability. The “one size fits most” diaphragm (Caya®) was introduced in the United States in 2014, and the FemCapTM cervical cap became available in Europe in 1999 and the United States in 2003. In addition, new designs of the male and female condoms have also emerged. Alternatives to nonoxynol-9 (N-9), the only spermicide currently approved by the FDA, have been under development for decades or available in countries other than the United States. In the past decade, early testing of MPT products that combine a barrier method and HIV prevention strategies, such as a single-sized diaphragm delivering an antiretroviral drug, has been initiated.


Protection from Sexually Transmitted Infections

Barrier methods (condoms and diaphragms) provide protection against STIs and pelvic infection,3,4,5,6,7 including infections due to chlamydia, gonorrhea, Trichomonas, herpes simplex, cytomegalovirus, and HIV. Couples should be counseled that consistent and correct use of the male latex condom reduces the risk for transmission of HIV and other STIs. Use of female condoms can provide protection from STIs, although data are limited. STI protection has a beneficial impact on the risk of tubal infertility and ectopic pregnancy.5,8 Women who have never used barrier methods of contraception are almost twice as likely to develop cervical cancer.8,9

Nonspermicidal male and FC2 female condom are indicated for preventing pregnancy, as well as HIV and other STIs. Condoms lubricated with N-9 and other barrier methods bear the label that they reduce the risk of pregnancy but do not protect against HIV/STIs.

The risk of toxic shock syndrome is increased with female barrier methods, but the actual incidence is so rare that this is not a significant clinical consideration.10 However, guidelines do indicate that the risks of diaphragm/spermicide use outweigh the advantages in women with a history of toxic shock syndrome (Medical Eligibility Criteria [MEC] category 3).11



The Diaphragm

The first effective contraceptive method under a woman’s control was the vaginal diaphragm. Distribution of diaphragms led to Margaret Sanger’s arrest in New York City in 1918. By 1940, one third of contracepting U.S. couples were using the diaphragm. Contraceptive provision was still a contentious issue in 1965 when the Supreme Court’s decision in Griswold v. Connecticut ended the ban on contraception in that state. By this time, diaphragm use had decreased to 10% of contraceptors following the introduction of oral methods and intrauterine devices (IUDs). By 1995, this rate fell to about 1.9%; today, less than 1% of U.S. women12 are diaphragm users. The Ortho All-Flex® diaphragm was the predominant diaphragm but the manufacturer opted to cease distribution in December 2013, leaving, at the time, only the Milex fitted silicone diaphragm in the United States (www.coopersurgical.com). Lower utilization led to decreased availability of vaginal diaphragms; today, most pharmacies no longer stock them routinely. A next-generation single-size method known as Caya (formerly SILCS) was developed by PATH and tested by CONRAD in an iterative process using clinician and end-user feedback to design a product that would be easier to use, more comfortable, more anatomically accurate, and easier to access. Caya (Figure 10.1) requires a prescription in the United States but is available over the counter or through Internet sales in many countries. Use of a contraceptive gel is recommended with both standard fitted diaphragms and Caya.


Efficacy

According to the most recent data from the National Survey of Family Growth, 12% of women using diaphragms experience pregnancy with typical use and 6% with perfect use.1,2 These numbers may underestimate both the risk of failure and success as the current group of users may not reflect historic patterns. Randomized comparator studies completed in the 1980s and 1990s reported typical-use failure as high as 29% and perfect-use failure as low as 2% among parous diaphragm users.13 While older married women with longer use achieve the highest efficacy, motivated young women
can use diaphragms very successfully if they are properly encouraged and counseled. There have been no adequate studies to determine whether efficacy is different with and without spermicides.14 A retrospective review of use patterns in Brazil found a lower rate of pregnancy (0.6% perfect, 2.8% typical use) in women who used the diaphragm continuously (removing only for bathing and then immediately reinserting) than in women following the traditional recommendations for pericoital use (6.5% perfect, 9.8% typical).15






Figure 10.1 Caya Diaphragm.


Side Effects

The diaphragm is a safe method of contraception that rarely causes even minor side effects. Although irritation from latex was occasionally reported in the past, latex products are no longer available. Still, some women experience vaginal irritation due to the gel used with the diaphragm or, less commonly, complain of discomfort from the diaphragm itself. Fewer than 1% discontinue diaphragm use for these reasons. Urinary tract infections are two to threefold more common among standard diaphragm users than among women using oral contraception.16,17 Possibly, the rim of the diaphragm presses against the urethra and causes irritation that is perceived as infectious in origin, or true infection may result from touching the perineal area or from incomplete emptying of the bladder. It is also possible that spermicides used with the diaphragm increase the risk of bacteriuria with E. coli, perhaps due to an alteration in the normal vaginal flora.18 Clinical experience suggests that voiding after sexual intercourse may help. In persistent cases, a single postcoital dose of a prophylactic antibiotic may prevent the development of infection. The single-size Caya diaphragm has an anterior notch designed to minimize urethral pressure and causes fewer urinary symptoms than does the standard diaphragm.19

Improper fitting or prolonged retention (beyond 24 hours) can cause vaginal abrasion or mucosal irritation. There is no link between the normal use of diaphragms and the development of toxic shock syndrome.20 It makes sense, however, to minimize the risk of toxic shock by not keeping the diaphragm in the vagina for more than 24 hours.


Benefits

Diaphragm use reduces the incidence of gonorrhea, Trichomonas, and chlamydia infection,21 pelvic inflammatory disease,5,22 and tubal infertility.3,8 There are no data, as of yet, regarding the effect of diaphragm use on the transmission of HIV, but because the vagina remains exposed, the diaphragm is unlikely to fully protect against HIV. Indeed, a clinical trial demonstrated no added benefit against HIV with a diaphragm when used with condoms.23 An important advantage of the diaphragm is low cost. Diaphragms are durable and with proper care can be used for 2 years or longer.


Choice and Use of the Diaphragm

Caya is a silicone barrier used with a contraceptive gel.19,24 It comes in one size that fits most women, and, therefore, interaction with a clinician and the requirement for fitting can be avoided, simplifying provision and access.
The Milex® Wide-Seal diaphragm is also made of silicone and comes in eight sizes (60 to 95 mm) that require fitting.


Fitting

A pelvic exam or traditional diaphragm fitting is not required for the single-sized contoured device, yet an initial fitting by the provider can help determine if the method is appropriate for the user. Caya is correctly placed when it completely covers the cervix.

During fitting of a standard diaphragm, the clinician must have available aseptic fitting rings or diaphragms in all diameters. Fitting kits are available through the manufacturer. The Milex Wide-Seal fitting devices should be scrubbed after each use with mild soap and autoclaved according to the fitting kit instructions. To measure the distance from the inside of the pubic symphysis to the posterior fornix, the index finger and middle finger are brought together and inserted into the vagina until the posterior fornix is reached. The examining hand is lifted so that the index finger makes contact with the pubic arch, and the point directly below the inferior margin of the pubic bone is noted with the tip of the thumb (Figure 10.2).

If the chosen diaphragm based on this measured distance is too tightly pressed against the pubic symphysis or is uncomfortable, a smaller size should be tried. If the diaphragm is too loose (comes out with a cough or bearing down), the next larger size should be tested. After a good fit is obtained, the diaphragm is removed by hooking the index finger under the rim behind the symphysis and pulling. It is important to instruct the patient in these procedures during and after the fitting. The patient should then insert the diaphragm (Figure 10.3A, B), practice checking for proper placement (Figure 10.3C), and attempt removal (Figure 10.3D) before leaving the office.


Timing

Diaphragm users need instruction about the timing of diaphragm use in relation to sexual intercourse and the use of spermicide. None of this advice has been rigorously assessed in clinical studies; therefore, these recommendations represent product instructions and the consensus of clinical experience.

About a tablespoonful of spermicide should be placed in the dome of the diaphragm prior to insertion, and some of the spermicide should be spread around the rim. The diaphragm should be left in place for at least 6 hours (but no more than 24 hours) after coitus. In the event of repeated intercourse, or if the diaphragm was inserted 2 or more hours before intercourse, additional spermicide should be placed in the vagina while the diaphragm is in place.


Reassessment

Weight loss or gain, vaginal delivery, and even sexual intercourse can change vaginal caliber. The fit of a standard diaphragm should be assessed during routine pelvic examinations or whenever the woman is concerned that the fit doesn’t seem correct.







Figure 10.2 Standard diaphragm fitting set.







Figure 10.3 A: Starting self-insertion of the standard diaphragm.







Figure 10.3 B: Completing self-insertion of the standard diaphragm.







Figure 10.3 C: Confirmation of correct position of the standard diaphragm behind the pubic bone (upper panel) and over the cervix (lower panel).







Figure 10.3 D: Technique for self-removal of the standard diaphragm.


Care of the Diaphragm

After removal, the diaphragm should be washed with soap and water, rinsed, and dried. It is wise to check for holes and tears before use and to use water to periodically check for leaks. Diaphragms should be stored within the supplied case in a cool and dark location. With proper care, the device should last at least 2 years.



The Cervical Cap

The only cervical cap that is currently widely available is the FemCap (FemCap, Inc. Del Mar, CA, www.femcap.com); the method requires a prescription in the United States but can be ordered without one elsewhere.25,26,27 FemCap is made of nonallergenic, durable silicone rubber, with a dome to cover the cervix, a rim that fits into the vaginal fornices, and an uneven brim that flares out and conforms to the vaginal walls around the cervix. These features trap sperm in the groove and minimize dislodgement.28 There are three inner rim diameter sizes, one for nulliparous women (22 mm), one for women who have been pregnant but not had a vaginal delivery (26 mm), and one for women who have had a vaginal delivery (30 mm). In a randomized trial, the pregnancy rate with FemCap was nearly twofold higher than a diaphragm, with 6-month cumulative typical-use pregnancy probabilities of 13.5% compared to 7.9%.29 The pregnancy rate was noticeably higher in women with previous vaginal deliveries.

Spermicide is placed in the bowl prior to placement over the cervix. It must remain inserted for at least 6 hours after intercourse and should not be left in the vagina for more than 48 hours. FemCap has a strap over the dome to aid in removal (Figure 10.4).






Figure 10.4 FemCap. A: FemCap features. B: The FemCap should cover the cervix completely. C: Example of incorrect FemCap placement. (Courtesy of FemCap Inc.)



The Contraceptive Sponge

Vaginal contraceptive sponges are soft, porous, single-size nonprescription devices designed for sustained spermicide release. Basically, the sponge is a spermicide product in a carrier that will block the entrance to the cervical canal and absorb semen, exposing the semen to concentrated spermicide.

The Today® sponge is a dimpled polyurethane disc impregnated with N-9 1 g and designed for use up to 24 hours including multiple acts of intercourse. Similar to other physical barriers, the device should remain in place for at least 6 hours after the last act of intercourse. Approximately 20% of the N-9 is released over the 24 hours that the sponge is left in the vagina.

Protectaid® is a polyurethane sponge not currently available in the United States that contains three spermicides and a dispersing gel.30 The spermicidal agents are sodium cholate, N-9, and benzalkonium chloride (BZK). This combination exerts antiviral actions in vitro.31 The dispersing agent, polydimethylsiloxane, forms a protective coating over the entire vagina, providing sustained protection. The Pharmatex sponge is a foam cylinder impregnated with 60 mg of the spermicide BZK that is also unavailable in the United States. The U.S. FDA requires efficacy data prior to marketing a contraceptive device, and only the Today sponge has complied with this requirement.

Prior to insertion in the vagina, the Today sponge is moistened with water (squeezing out the excess) and then placed firmly against the cervix. It can be inserted immediately before sexual intercourse or up to 24 hours beforehand. There should always be a lapse of at least 6 hours after sexual intercourse before removal, even if the sponge has been in place for 24 hours before intercourse (maximal wear time, therefore, is 30 hours). It is removed by hooking a finger through the ribbon attached to the back of the sponge. The Protectaid and Pharmatex sponges do not require moistening and can be inserted up to 12 hours before intercourse. Some reports suggest that these may be easier to remove than the Today sponge. Obviously, the sponge is not a good choice for women with anatomic changes that make proper insertion and placement difficult.

The effectiveness of the sponge is similar to that of spermicide with a typical failure rate during the first year of 27% and 14% in parous and nulliparous women, respectively.1,2,32,33 This disparity in efficacy suggests that one size may not fit all users and the sponge may not adequately cover the larger parous cervix.34 In comparator studies, the sponge is also inferior to the diaphragm.13

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Mar 1, 2020 | Posted by in OBSTETRICS | Comments Off on Barrier Methods of Contraception
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