Contraception 101: Methods and Effectiveness

Contraception is the use of artificial or behavioral methods to prevent pregnancy as a consequence of sexual intercourse. It is a word that invokes many different emotions, but primarily, contraceptive methods are devices or procedures used to prevent sperm from fertilizing an egg to avoid pregnancy. Contraception includes ingestives, like the birth control pill, devices, like male and female condoms, and behavioral methods, such as abstinence and the withdrawal method.

Barrier Methods and STI Protection

Condoms are made from latex and act as a barrier to prevent sperm from entering the vagina, anus, or mouth. Male condoms are placed on an erect penis for sex, while the female condom is inserted in the vagina. Condoms are 85 percent effective and help protect you from sexually transmitted infections (STIs) like herpes, chlamydia and human papillomavirus infection. The World Health Organization states that the correct and constant use of condoms has been proven to be one of the most effective methods against STIs. Conversely, dental dams prevent STI transmission during oral sex but are not intended to be used to prevent pregnancy.

Long-Acting Reversible Contraception

Subdermal Implant

This is a small rod, approximately 4cm long, which a medical professional introduces in the person’s arm below the skin. It contains low doses of progestin, which hinders ovulation, changes the endometrial consistency, and thickens cervical mucus. This is a highly effective method that lasts approximately five years. Although the subdermal implant is a very effective contraceptive method, it does not protect against sexually transmitted infections.

Intrauterine Contraception

An intrauterine device (IUD), which is inserted into the uterus, is 99 percent effective but also does not prevent STI transmission. There are two main types:

• Copper intrauterine device (IUD): This is a T-shaped rod wrapped in copper. The copper damages the sperm and prevents its passage.
• Intrauterine system (IUS): This is a small T-shaped device that constantly releases small amounts of levonorgestrel to suppress ovulation.

Intrauterine contraception is very effective for 5 to 7 years depending on the type of device and medical recommendation.

Hormonal Methods

The birth control pill, when used exactly as prescribed, is 99 percent effective, but in practice, the pill is 91 percent effective due to missed pills and other complications. Combined oral contraceptives contain estrogen and progestin to prevent the release of eggs from the ovaries. Progestogen-only pills, also known as the minipill, thicken the cervical mucus to prevent sperm from joining the egg. Other hormonal options include:

• Contraceptive injections: Administered every two or three months (progestogen-only) or monthly (combined).
• Contraceptive patch: A small patch placed on the skin that continuously releases hormones.
• Vaginal ring: Helps prevent pregnancy but fails to prevent STIs.

Emergency Contraceptive Pills

Commonly known as the morning-after-pills, these contain hormones which prevent ovulation. They are highly effective when taken within 72 hours, but they work up to five days after sex. These can be taken after unprotected sex, after rape, or when a condom tears.

Sterilization and Behavioral Methods

Sterilization is a very effective contraception method, but it does not protect against STIs. Female sterilization, known as tubal ligation, involves blocking the fallopian tubes. Male sterilization, or a vasectomy, cuts the tubes that allow sperm to pass into semen. However, the only 100 percent effective method of preventing STIs and pregnancy is abstinence.

Additional Health Benefits

Contraception can be used for certain purposes other than preventing pregnancy. The birth control pill is often used to lighten periods, reduce menstrual cramps and subdue premenstrual syndrome. According to Planned Parenthood, the combination pill may also reduce or help prevent:

• Acne and anemia
• Bone thinning
• Cysts in the breasts and ovaries
• Endometrial and ovarian cancers
• Serious infections in the reproductive system

Effectiveness Comparison

Based on the provided data, here is a summary of method effectiveness:

• Abstinence: 100% effective against pregnancy and STIs.
• Intrauterine Device (IUD): 99% effective against pregnancy.
• Birth Control Pill: 91% to 99% effective against pregnancy.
• Condoms: 85% effective against pregnancy; effective against STIs.