Master Contraception Methods for USMLE

Various methods of contraception, including both barrier and hormonal methods, can be used to prevent unwanted or unplanned pregnancies.

Spermicides, such as nonoxynol-9 (N-9) serve as a chemical barrier to conception, working to reduce the motility of the sperm and reducing the likelihood that the sperm will reach the cervix. Foams, tablets, suppositories, creams, films, and gels are types of intravaginal spermicides. This method of contraception can be used with a diaphragm and must be reapplied before each act of intercourse at least 15 minutes before and no longer than 1 hour before to maintain effectiveness.

A diaphragm is a dome-shaped device, typically made of latex or silicone, that is designed to cover the cervix. Keep in mind, a diaphragm is more effective when used with a spermicide. It is important to educate the patient that the device should be removed six to eight hours after intercourse to maximize contraception and to prevent toxic shock syndrome. Women will need an annual gynecologic exam to reassess fit of the diaphragm and may need to be refitted if there is a 20% weight fluctuation, abdominal or pelvic surgery, and after every pregnancy.

A cervical cap is a device that fits around the base of the cervix, acting as a physical barrier to sperm. Cervical caps also contain spermicide, which provides an additional chemical barrier to sperm. The cervical cap should be left in place for at least 6 hours after intercourse, but it should not remain in place longer than 48 hours.

The vaginal sponge is a spermicide-containing, sponge-like device designed to fit over a woman’s cervix. The sponge should be left in place for at least six hours after intercourse, but not longer than 24-30 hours at a time. A contraceptive sponge must be moistened with water before inserting.

Male condoms are applied over the erect penis and are intended for one time use only. It is important to check the expiration date before each use and refrain from using petroleum-based lubricants, as these can interfere with the integrity of the barrier. Remember, an empty space should be left at the tip of the condom to collect ejaculated sperm.

Oral contraceptive medications work by suppressing the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), thereby preventing ovulation and subsequently preventing pregnancy. These medications should not be used in patients with thromboembolic disorders due to increased risk of stroke.

Intrauterine devices (IUDs) are inserted through a woman’s cervix and placed against the uterine fundus. Both hormonal and nonhormonal IUDs are available. Hormonal IUDs are loaded with progestin and work by irritating the lining of the uterus and decreasing sperm motility. They are effective for up to 5 years. Non-hormonal IUDs, such as the ParaGard Copper T 380A IUD, work by inflaming the endometrium and preventing fertilization and are approved for 10 years of use. Remember, before an IUD can be placed, a woman must have a negative pregnancy test.

Injectable progestins can be administered intramuscularly every 12 weeks. With this type of contraception, it is important to avoid massaging the injection site, as it shortens the medication’s period of effectiveness. Implantable progestin rods (e.g. Nexplanon in the USA) are also available and are effective in preventing pregnancy for up to three years. Again, do not massage the injection site, as it can hasten absorption and shorten the period of effectiveness.