For "Postcoital douche method" of contraception, select the most appropriate rate of use effectiveness (failure rate or percentage of pregnancies per year of actual patient use). (SELECT 1 RATE)
There are two methods of describing the effectiveness of contraceptive agents: the theoretical or method effectiveness rate and the actual use effectiveness rate. When comparing different methods, it is important to use comparable figures. The effectiveness of the rhythm method is influenced by the woman's ability to predict the time of ovulation from the regularity of her menses, and by her motivation to successfully abstain from intercourse during the 10 days around suspected ovulation. The menstrual and ovulatory irregularities and lapses in the woman's motivation account for a pregnancy rate of 40% with the rhythm method. In contrast to the rhythm method, the IUD requires little or no action on the part of the woman. For this reason the device's actual use effectiveness approaches its maximal theoretical effectiveness, with a pregnancy rate of 3 to 10%. Unrecognized expulsion or misplaced insertion of the IUD are responsible for most failures. The vaginal diaphragm and the condom are barrier contraceptives in that for each act of sexual intercourse they pose a barrier between the sperm ejaculate and the endocervical canal. In theory, both can be very effective. However, both require recurrent motivation for application with each act of intercourse. Lapses in motivation are not uncommon, and there is a pregnancy rate of 15 to 25% for each of these two methods. The condom used with a spermicidal agent is very effective, more so than either used alone. The pregnancy rate with postcoital douching is almost the same as that for unprotected intercourse (80%). This lack of effectiveness is readily explained by the extremely rapid progression of motile sperm into the endocervical canal. Within several minutes of coitus, sperm have ascended the female reproductive tract and can be found within the endocervical mucus, uterus, and fallopian tubes. Coupled with the failure of a vaginal douche to reach the endocervix, this method is essentially useless. Combined oral contraceptive birth control pills are clearly the most effective reversible contraceptive currently available. With correct use, many studies report a contraceptive effectiveness that approaches 100% (pregnancy rate less than 0.1%). This extreme effectiveness is best explained by the pill's multiplicity of actions, i.e., suppression of ovulation, hostility of cervical mucus to sperm penetration, and hostility of atrophic endometrium to the implantation of a conceptus. Failure to take the pills regularly is responsible for most failures, and in practice pregnancy rates of at least 5% are common.
80%
40%
15 to 25%
5 to 15%
Contraceptives