Barrier Methods

Barrier Methods

 

1. Diaphragms and cervical cap: These have about the same rate of effectiveness.

a. Composition and use of diaphragm.

(1) The diaphragm is a dome-shaped rubber cup with a flexible rim.

(2) It fits in the vagina between the symphysis pubis and the posterior fornix of the vagina, covering the cervix.

(3) It must be used with contraceptive gel.

(4) It is effective for 6 hours.

(5) The diaphragm is not to be worn more than 24 hours (risk of toxic shock syndrome).

(6) The size is 50 to 95 mm.

(7) Disposable diaphragms packaged with spermicide are being developed for single use.

(8) Types.

Types of diaphragms

Types of diaphragms

(a) Flat spring rim: good for women with good vaginal muscle tone

(b) Coil spring: good for women with average muscle tone and average pubic arch depth

(c) Arcing spring: good for poor vaginal muscle tone

(d) Wide seal: arcing or coil spring

b. Cervical cap .

Cervical cap

Cervical cap

(1) A deep rubber cup, smaller than the diaphragm and fits snugly over the cervix only (Prentif cavity rim cervical cap)

(2) Must be one-third filled with contraceptive gel, effective continuously for 48 hours

(3) May repeat intercourse without additional spermicide

(4) Not to be left in more than 48 hours, may cause toxic shock syndrome

c. Fitting a diaphragm.

(1) Domed and fitting rings are available,

(2) The average size is 70 to 75 mm.

(3) Vaginal depth is estimated by inserting the middle and index finger into the posterior fornix of the vagina; the thumb will mark the pubic bone.

(4) Several rings or dome sizes should be used to get the best fit, which is the tighter but comfortable fit.

d. Fitting a cervical cap (the Femcap and Lea shield are now marketed).

(1) The cervical cap is available in sizes 22, 25, 28, and 31 mm.

(2) Six percent to ten percent of patients are unable to be fitted.

(3) When the cap is fitted, it should be the exact diameter (within a few millimeters only) of the base of the cervix.

(4) The dome should not be tight to the cervix.

(5) If the cap is too tight, it will cause cervical trauma.

(6) The rim of the cap forms suction around the cervix.

e. Efficacy of female barriers.

11) All types of barriers have a failure rate of 5% to 9% in nulliparous and 5% to 26% in multiparous users in the first year of use.

(2) Failures are also more likely to occur in women who have intercourse three or more times weekly or are less than 25 years old.

(3) Increased failures result from use with oil-based lubricants such as mineral oil, baby oil, suntan oil, butter, vaginal medications, yeast preparations, estrogen creams, and Vagisil. Latex will break down.

f. The vaginal sponge is again available. It releases nonoxynol 9, soaks up sperm, and is a physical barrier. The sponge was discontinued in the United States in 1995, but the Protectaid Sponge is available on the Internet.

g. Advantages of female barrier methods.

(1) No systemic side effects

(2) Efficacy equal to condoms

(3) Good for women who are much less sexually active

(4) Protection against sexually transmitted diseases such as gonorrhea, Chlamydia, cervical intraepithelial neoplasia

h. Side effects and contraindications.

(1) Allergy to spermicide, rubber, latex, or polyurethane

(2) Abnormalities in anatomy (may affect the fit)

(3) Patient insertion error

(4) May cause recurrent urinary tract infections

(5) History of toxic shock syndrome

(6) Lack of experience in fitting cap/diaphragm

(7) Vaginal bleeding

(8) Should not be used before 6 weeks postpartum

(9) Known malignancy (cervix, uterus)

(10) Unresolved Papanicolaou smears or infections of the genital tract

 

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