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Cervical cap
Image:Cape cervicale.jpg
Oves brand cervical cap
Background
B.C. type	Barrier
First use	1838
Failure rates (per year, Prentif)
Perfect use	Nulliparous:9% Parous:26%
Typical use	Nulliparous:16% Parous:32%
Usage
Reversibility	Immediate
User reminders	Inserted with spermicide and left in place for 8 hours after intercourse
Clinic review	For fitting and subsequent replacements
Advantages
STD protection	Possible
Benefits	May be left in place for 48-72 hours
Disadvantages
Weight gain	No

The cervical cap is a cervical barrier type of birth control. It fits snugly over the cervix, the entrace of the uterus, and blocks sperm from entering the female reproductive tract. Cervical caps may be made out of latex or silicone.

Contents 1 Use 2 Types 3 Fitting 4 Effectiveness 4.1 Method effectiveness 4.2 Actual effectiveness 5 History 6 See also 7 External links 8 Footnotes

[edit] Use

Anyone inserting or removing a cervical cap should first wash their hands,<ref name="pp">Johnson, Jennifer (December 2005). Diaphragms, Caps, and Shields. Planned Parenthood. Retrieved on 2006-10-15.</ref> to avoid introducing harmful bacteria into the vaginal canal.

The cervical cap must be inserted sometime before sexual intercourse, and remain in the vagina for at least 8 hours after a man's last ejaculation.<ref name="CBAS">Cervical Caps. Cervical Barrier Advancement Society (March 2005). Retrieved on 2006-10-29.</ref> It is usually recommended to apply spermicide inside the cap,<ref name="pp" /> <ref name="CBAS" /> but some sources say spermicide use is optional.<ref name="fpn">Cervical Cap. Family Practice Notebook (2000). Retrieved on 2006-10-29.</ref> <ref name="fwhc2">Cervical Cap - Q&A. Feminist Women's Health Center (January 2006). Retrieved on 2006-10-29.</ref> The cap must be removed within 72 hours (within 48 hours recommended in the U.S.)<ref name="CBAS" /> It should be washed with warm soapy water before storage.<ref name="fwhc">Cervical Cap. Feminist Women's Health Center (September 2006). Retrieved on 2006-10-29.</ref>

Oil-based products should not be used with latex cervical caps. Lubricants or vaginal medications that contain oil will cause the latex to rapidly degrade and greatly increases the chances of the cap breaking or tearing.<ref name="fwhc" />

Cervical caps should be replaced about every two years.<ref name="pp" />

[edit] Types

Cavity rim caps adhere to the cervix. Prentif and Oves are cavity rim caps. Prentif is made of latex, and is available in sizes 22, 25, 28, and 31mm. Oves is a silicone, "disposible" cap that is replaced frequently. Unlike other caps, Oves adheres to the cervix by surface tension, rather than by suction. Some users may find the thinner walls of the Oves cap make it more comfortable. It is available in sizes 26, 28, and 30mm.<ref name="CBAS" />

Other caps adhere to the vaginal walls around the cervix. The Dumas and Vimule caps are made of latex, while FemCap is made of silicone. Dumas, also called a vault cap, comes in five sizes: 50, 55, 60, 65, and 75mm. Vimule comes in three sizes: 42, 48, and 52mm. FemCap comes in three sizes: 22, 26, and 30mm.<ref name="CBAS" /> Each one of these devices fits differently over the cervix; a woman fitted for one type of cap cannot use that measurement as her size for a different type of cap.

There is also a larger cap-like device called the Lea's shield. This device is made of silicone, and designed to be one-size-fits-all.

Only Prentif, FemCap, and the Lea's shield are approved for use in the United States. Although other brands are available over-the-counter in some countries (and so over the internet), they may be confiscated by U.S. customs if imported into the country.

[edit] Fitting

Screening by a health care provider is necessary to determine if a cervical cap, or one brand of cap, is appropriate for a particular woman. If a cap is determined to be appropriate, the provider will also make a size determination.

Women who have given birth may have scar tissue or irregularly shaped cervixes that interfere with the cap adhering to the cervix or the nearby vaginal walls.<ref name="fwhc2" /> Some women are good cadidates for caps even after vaginal birth, but an examination by an experienced provider is necessary to determine this.

Cavity rim caps are not appropriate for most women with an anteflexed uterus.<ref> (1989) "Uncertainty exists on availability of cervical cap, distributor says". Contracept Technol Update 10 (4): 57-8. PMID 12342202.</ref> This presentation of the cervix put such caps at high risk of being dislodged during intercourse. Women with anteflexed uteruses may still safely wear other types of caps.

Some women may not be able to wear a particular cap because it is not made in their size. The three to five sizes offered by cap manufacturers do not encompass the entire range of normal female anatomy.

Cervical caps should be refitted after any pregnancy.<ref name="pp" /> Although full-term vaginal delivery especially is likely to change the size a woman wears, changes to the cervix during pregnancy mean even women who experience miscarriage, or have a C-section should be refitted.

Obtaining a fitting appointment may be difficult for some women. A 1997 survey in the United States found that most family medicine residents had no experience with prescription methods of birth control other than oral contraceptives.<ref>Steinauer J, DePineres T, Robert A, Westfall J, Darney P. "Training family practice residents in abortion and other reproductive health care: a nationwide survey.". Fam Plann Perspect 29 (5): 222-7. PMID 9323499.</ref> In many countries, the cervical cap is the least common prescription method of birth control. A number of women in the Yahoo! DiaphragmsAndCaps group have reported their only route to obtaining a cervical cap was to purchase their own fitting kit, and take it to a doctor who had no previous experience fitting caps.

[edit] Effectiveness

The effectiveness of cervical caps, as of most forms of contraception, can be assessed two ways: method effectiveness and actual effectiveness. The method effectiveness is the proportion of couples correctly and consistently using the method who do not become pregnant. Actual effectiveness is the proportion of couples who intended that method as their sole form of birth control and do not become pregnant; it includes couples who sometimes use the method incorrectly, or sometimes not at all. Rates are generally presented for the first year of use. Most commonly the Pearl Index is used to calculate effectiveness rates, but some studies use decrement tables.

Cervical caps are not appropriate for 20-40% of women.<ref>Secor R (1992). "The cervical cap". NAACOGS Clin Issu Perinat Womens Health Nurs 3 (2): 236-45. PMID 1596432.</ref> It is not clear if such women were excluded from all studies of cap effectiveness, and some sources imply that appropriately fitted parous women (women who have given birth), especially, may experience lower failure rates than these studies imply.<ref name="fwhc2" />

[edit] Method effectiveness

Contraceptive Technology reports that the method failure rate of the cervical cap with spermicide is 9% per year for nulliparous women (women who have never given birth), and 26% per year for parous women.<ref name="hatcher">Hatcher, RA, Trussel J, Stewart F, et al (2000). Contraceptive Technology, 18th Edition, New York: Ardent Media. ISBN 0-9664902-6-6.</ref> This appears to be based on a study of about 700 women using the Prentif cap.<ref name="barriers">Trussell J, Strickler J, Vaughan B (1993). "Contraceptive efficacy of the diaphragm, the sponge and the cervical cap". Fam Plann Perspect 25 (3): 100-5, 135. PMID 8354373.</ref>

In a multicenter trial involving 581 users of the Prentif cap, the method failure rate was 7% over two years.<ref name="multicenter"> (1988) "The cervical cap". Med Lett Drugs Ther 30 (776): 93-4. PMID 3050407.</ref> In a 1980s study of over three thousand users of the Prentif cap, the method failure rate was 4% per year.<ref name="eighties">Richwald G, Greenland S, Gerber M, Potik R, Kersey L, Comas M (1989). "Effectiveness of the cavity-rim cervical cap: results of a large clinical study". Obstet Gynecol 74 (2): 143-8. PMID 2664609.</ref>

Comparative trials with the diaphragm have found that the Prentif cap has a similar method failure rate as the diaphragm<ref name="compare">Gallo M, Grimes D, Schulz K. "Cervical cap versus diaphragm for contraception". Cochrane Database Syst Rev: CD003551. PMID 12519602.</ref> (which Contraceptive Technology reports as 6% per year).<ref name="hatcher" /> However, the FemCap was found to have a higher failure rate.<ref name="compare" />

[edit] Actual effectiveness

For all forms of contraception, actual effectiveness is lower than method effectiveness, due to several factors:

• mistakes on the part of those providing instructions on how to use the method
• mistakes on the part of the method's users
• conscious user non-compliance with method.

For instance, someone using a cervical cap might be fitted incorrectly by a health care provider, or by mistake remove the cap too soon after intercourse, or simply choose to have intercourse without placing the cap.

The actual pregnancy rates among cap users vary depending on the population being studied, with yearly rates of 11%<ref name="eighties" /> to 32%<ref name="hatcher" /> being reported.

[edit] History

The idea of blocking the cervix to prevent pregnancy is thousands of years old. Various cultures have used cervix-shaped devices such as oiled paper cones or lemon halves, or have made sticky mixtures that include honey or cedar rosin to be applied to the cervical opening.<ref name="pp2">A History of Birth Control Methods. Planned Parenthood (June 2002). Retrieved on 2006-07-05.</ref> However, the modern idea of a cervical cap as a fitted device that seals itself against the vaginal walls is of much more recent origin.

In 1838, German gynecologist Friedrich Wilde created the first modern cervical cap by making custom-made rubber molds of their cervix for some of his patients.<ref name="pp2" /> How many times these caps could be used is questionable, as uncured rubber degrades fairly quickly. An important precursor to the invention of more lasting caps was the rubber vulcanization process, patented by Charles Goodyear in 1844.

Over the next several decades, the cervical cap became the most widely used barrier contraceptive method in Western Europe and England. Although the diaphragm was always more popular in the U.S. than the cervical cap, the cap was also common.<ref name="weiss">Weiss B, Bassford T, Davis T (February 1991). "The cervical cap". Am Fam Physician 43 (2): 517-23. PMID 1990736.</ref>

A large number of types of cap were developed in the later nineteenth and early twentieth. Some of these caps are still available today. The Vimule cap has been available since at least 1927.<ref>the Vimule permanent sheath, as purveyed by Lamberts of London, 1927. Condom pictures. Retrieved on 2006-11-12.</ref> The Prentif brand cap was introduced in the early 1930s.<ref> (Winter 2002). "Cervical Cap Newsletter". Cervical Cap Ltd. Retrieved on 2006-11-12. (Google cache version; Cervical Cap Ltd. went out of business in March 2005.)</ref> The Dumas cap was initially made of plastic and was available by the 1940s.<ref>Grafenberg E, Dickinson R (1944). "Conception control by plastic cervix cap". West J Surg Obstet Gynecol 12 (8): 335-40. PMID 12233290.</ref> (Lamberts (Dalston) Ltd., a U.K. company, manufacturers these three cap types.)<ref>96/281/2 Contraceptive cervical cap, 'Vimule' cap. Powerhouse Museum Collection (1995). Retrieved on 2006-11-12.</ref><ref name= "CBAS" /> Other types of caps had stems to hold them in place in the cervix; some of the stems actually extended into the uterus. These "stem pessaries" became precursors to the modern intrauterine device.<ref name="slides">Lynch, Catherine M.. History of the IUD. Contraception Online. Baylor College of Medicine. Retrieved on 2006-07-09.</ref>

Use of all barrier methods, but especially cervical barriers, dropped dramatically after the 1960s introduction of the oral contraceptive pill and the intrauterine device. In 1976, the U.S. government enacted the Medical Device Amendment. This law required all manufacturers of medical devices to provide the FDA with data on the safety and efficacy of those devices. Lamberts (Dalston) Ltd., the only manufacturer at that time, failed to provide this information, and the FDA banned the use of cervical caps in the United States.<ref name="weiss" />

In the late 1970s, the FDA reclassified the cervical cap as an investigational device, and it regained very limited availibility.<ref>Fairbanks B, Scharfman B (1980). "The cervical cap: past and current experience". Women Health 5 (3): 61-80. PMID 7018094.</ref> Within a few years, the FDA withdrew investigational status from the Vimule cap because of a study that associated it with vaginal lacerations.<ref>Bernstein G, Kilzer L, Coulson A, Nakamura R, Smith G, Bernstein R, Frezieres R, Clark V, Coan C (1982). "Studies of cervical caps: I. Vaginal lesions associated with use of the Vimule cap.". Contraception 26 (5): 443-56. PMID 7160179.</ref><ref name="weiss" /> In 1988, the Prentif cap gained FDA approval.<ref>"Notice, 11 July 1988". Annu Rev Popul Law 15: 19. PMID 12289360.</ref> The feminist movement played a large role in re-introducing the cervical cap to the U.S. One paper called its involvement at all steps of the FDA approval process "unprecedented."<ref>Gallagher D, Richwald G (1989). "Feminism and regulation collide: the Food and Drug Administration's approval of the cervical cap". Women Health 15 (2): 87-97. PMID 2781812.</ref>

Today, the cervical cap is one of the least common methods of contraception. In 2002, 0.6% of American women used either the cervical cap, contraceptive sponge, or female condom as their primary method of contraception.<ref>William D. Mosher, Gladys M. Martinez, Anjani Chandra, Joyce C. Abma, and Stephanie J. Willson (2002). "Use of Contraception and Use of Family Planning Services in the United States: 1982–2002. Advance Data No. 350" (PDF). Center for Disease Control. Retrieved on 2006-09-14.</ref> Manufacturers seem to believe interest in caps is increasing, however, and are bringing new products to market. The Oves cap became available in the U.K. in 2001,<ref>About Veos. Oves (manufacturer website) (2001). Retrieved on 2006-11-12.</ref> and the FDA approved the Lea's Shield in 2002<ref> (March 2002). "Lea's Shield approval letter" (PDF). United States Food and Drug Administration. Retrieved on 2006-11-12.</ref> and the FemCap in 2003.<ref> (March 2003). "FemCap approval letter" (PDF). United States Food and Drug Administration. Retrieved on 2006-11-12.</ref>

[edit] See also

• Contraceptive sponge
• Diaphragm (contraceptive)
• Lea's shield

[edit] External links

• Cervical Barrier Advancement Society
• Diaphragms and Caps (Yahoo Group)

[edit] Footnotes

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