All you need to know about contraception

OVERVIEW

First of all, what is contraception? Also known as birth control or fertility control, contraception is a method or device to prevent pregnacy.
The most effective methods of birth control are sterilization by means of vasectomy in males and tubal ligation in females, intrauterine devices and implantable contraceptives. This is followed by a number of hormonal contraceptives including oral pills, patches, vaginal rings, and injections. Less effective methods include barriers such as condoms, diaphragms and contraceptive sponge and fertility awareness methods. The least effective methods are spermicides and withdrawal by the male before ejaculation.
Sterilization, while highly effective, is not usually reversible; all other methods are reversible, most immediately upon stopping them. Safe sex, such as the use of male or female condoms, can also help prevent sexually transmitted infections (STD). Emergency contraceptives can prevent pregnancy in the few days after unprotected sex.
Some regard sexual abstinence as birth control, but abstinence-only sex education may increase teen pregnancies when offered without contraceptive education.

Methods
Birth control methods include barrier methods, hormonal birth control, intrauterine devices, sterilization, and behavioral methods. They are used before or during sex while emergency contraceptives are effective for up to a few days after sex. The most effective methods are those that are long acting and do not require ongoing health care visits. Surgical sterilization, implantable hormones and intrauterine devices all have first-year failure rates of less than 1%.
Hormonal contraceptive pills, patches or vaginal rings, and the lactational amenorrhea method, if used strictly, can also have first-year failure rates of less than 1%.
Other methods such as condoms, diaphragms, and spermicides have higher first-year failure rates even with perfect usage.
While all methods of birth control have some potential adverse effects, the risk is less than that of pregnancy. After stopping or removing many methods of birth control, including oral contraceptives, IUDs, implants and injections, the rate of pregnancy during the subsequent year is the same as for those who used no birth control.
In those with specific health problems, certain forms of birth control may require further investigations. For women who are otherwise healthy, many methods of birth control should not require a medical exam - including birth control pills, injectable or implantable birth control and condoms. Specifically, a pelvic exam, breast exam or blood test before starting birth control pills do not appear to affect outcomes and, therefore, are not required.


Hormonal
Hormonal contraception is available in a number of different forms, including oral pills, implants under the skin, injections, patches, IUDs and a vaginal ring. They are currently available only for women, although hormonal contraceptives for men have and are being clinically tested. There are two types of oral birth control pills, the combined oral contraceptive pills (which contain both progesterone and oesrogen) and the progestogen-only pills (sometimes called minipills). Both types of birth control pills prevent fertilization mainly by inhibiting ovulation and thickening cervical mucous. Their effectiveness depends on the user remembering to take the pills. They may also change the lining of the uterus and thus decrease implantation.

Combined hormonal contraceptives are associated with a slightly increased risk of venous and arterial blood clots.Venous clots, on average, increase from 2.8 to 9.8 per 10,000 women years which is still less than that associated with pregnancy. Due to this risk, they are not recommended in women over 35 years of age who continue to smoke. The effect on sexual desire is varied, with increase or decrease in some but with no effect in most. Combined oral contraceptives reduce the risk of ovarian cancer and endometrial cancer and do not change the risk of breast cancer. They often reduce menstrual bleeding and painful menstruation cramps. The lower doses of estrogen released from the vaginal ring may reduce the risk of breast tenderness, nausea and headache associated with higher dose estrogen products.

Progestin-only pills, injections and intrauterine devices are not associated with an increased risk of blood clots. In those with a history of arterial blood clots, non-hormonal birth control or a progestin-only method other than the injectable version should be used. Progestin-only pills may improve menstrual symptoms and can be used by breastfeeding women as they do not affect milk production. Irregular bleeding may occur with progestin-only methods, with some users reporting no periods. The progestins, drospirenone and desogestrel minimize the androgenic side effects but increase the risks of blood clots and are thus not first line. The perfect use first-year failure rate of the injectable progestin, Depo-Provera, is 0.2%; the typical use first failure rate is 6%.


Barrier
Barrier contraceptives are devices that attempt to prevent pregnancy by physically preventing sperm from entering the uterus. They include male condoms, female condoms, cervical caps, diaphragms, and contraceptive sponges with spermicide.
Globally, condoms are the most common method of birth control. Male condoms are put on a man's erect penis and physically block ejaculated sperm from entering the body of a sexual partner. Modern condoms are most often made from latex, but some are made from other materials such as polyurethane, or lamb's intestine. Female condoms are also available, most often made of nitrile, latex or polyurethane.
Male condoms have the advantage of being inexpensive, easy to use, and have few adverse effects.

Male condoms and the diaphragm with spermicide have typical use first-year failure rates of 18% and 12%, respectively. With perfect use, condoms are more effective with a 2% first-year failure rate versus a 6% first-year rate with the diaphragm. Condoms have the additional benefit of helping to prevent the spread of some sexually transmitted infections such as HIV/AIDS.

Contraceptive sponges combine a barrier with a spermicide. Like diaphragms, they are inserted vaginally before intercourse and must be placed over the cervix to be effective. Typical failure rates during the first year depend on whether or not a woman has previously given birth, being 24% in those who have and 12% in those who have not. The sponge can be inserted up to 24 hours before intercourse and must be left in place for at least six hours afterward. Allergic reactions and more severe adverse effects such as toxic shock syndrome have been reported.


Intrauterine devices
The current intrauterine devices (IUD) are small devices, often 'T'-shaped, often containing either copper or levonorgestrel, which are inserted into the uterus. They are one form of long-acting reversible contraception which are the most effective types of reversible birth control. Failure rates with the copper IUD is about 0.8% while the levonorgestrel IUD has a failure rates of 0.2% in the first year of use. Among types of birth control, they along with birth control implants result in the greatest satisfaction among users. As of 2007, IUDs are the most widely used form of reversible contraception, with more than 180 million users worldwide.
IUDs do not affect breastfeeding and can be inserted immediately after delivery. They may also be used immediately after an abortion. Once removed, even after long term use, fertility returns to normal immediately.
While copper IUDs may increase menstrual bleeding and result in more painful cramps, hormonal IUDs may reduce menstrual bleeding or stop menstruation altogether. Cramping can be treated with NSAIDs. Other potential complications include expulsion (2-5%) and rarely perforation of the uterus (less than 0.7%).

Sterilization
Surgical sterilization is available in the form of tubal ligation for women and vasectomy for men. There are no significant long-term side effects, and tubal ligation decreases the risk of ovarian cancer. Short term complications are twenty times less likely from a vasectomy than a tubal ligation. After a vasectomy, there may be swelling and pain of the scrotum which usually resolves in a week or two. With tubal ligation, complications occur in 1 to 2 percent of procedures with serious complications usually due to the anesthesia. Neither method offers protection from sexually transmitted infections.

This decision may cause regret in some men and women. Of women aged over 30 who have undergone tubal ligation, about 5% regret their decision, as compared with 20% of women aged under 30. By contrast, less than 5% of men are likely to regret sterilization. Men more likely to regret sterilization are younger, have young or no children, or have an unstable marriage. In a survey of biological parents, 9% stated they would not have had children if they were able to do it over again.

Although sterilization is considered a permanent procedure, it is possible to attempt a tubal reversal to reconnect the fallopian tubes or a vasectomy reversal to reconnect the vasa deferentia. In women the desire for a reversal is often associated with a change in spouse. Pregnancy success rates after tubal reversal are between 31 and 88%, with complications including an increased risk of ectopic pregnancy. The number of males who request reversal is between 2 and 6%. Rates of success in fathering another child after reversal are between 38 and 84%; with success being lower the longer the time period between the original procedure and the reversal. Sperm extraction followed by in vitro fertilization may also be an option in men.

Behavioral
Behavioral methods involve regulating the timing or method of intercourse to prevent introduction of sperm into the female reproductive tract, either altogether or when an egg may be present. If used perfectly the first-year failure rate may be around 3.4%, however if used poorly first-year failure rates may approach 85%.


Fertility awareness
Fertility awareness methods involve determining the most fertile days of the menstrual cycle and avoiding unprotected intercourse. Techniques for determining fertility include monitoring basal body temperature, cervical secretions, or the day of the cycle. They have typical first-year failure rates of 24%; perfect use first-year failure rates depend on which method is used and range from 0.4% to 5%. The evidence on which these estimates are based, however, is poor as the majority of people in trials stop their use early. Globally, they are used by about 3.6% of couples. If based on both basal body temperature and another primary sign, the method is referred to as symptothermal. Overall first-year failure rates of 2% to 20% have been reported in clinical studies of the symptothermal method.

Withdrawal
The withdrawal method (also known as coitus interruptus) is the practice of ending intercourse ("pulling out") before ejaculation. The main risk of the withdrawal method is that the man may not perform the maneuver correctly or in a timely manner. First-year failure rates vary from 4% with perfect usage to 22% with typical usage. It is not considered birth control by some medical professionals.
There is little evidence regarding the sperm content of pre-ejaculatory fluid. While some tentative research did not find sperm, one trial found sperm present in 10 out of 27 volunteers. The withdrawal method is used as birth control by about 3% of couples.

Abstinence
Though some groups advocate total sexual abstinence, by which they mean the avoidance of all sexual activity, in the context of birth control the term usually means abstinence from vaginal intercourse. Abstinence is 100% effective in preventing pregnancy; however, not everyone who intends to be abstinent refrains from all sexual activity and in many populations there is a significant risk of pregnancy from nonconsensual sex.
Abstinence-only sex education does not reduce teenage pregnancy. Teen pregnancy rates are higher in students given abstinence-only education, as compared with comprehensive sex education. Some authorities recommend that those using abstinence as a primary method have backup method(s) available (such as condoms or emergency contraceptive pills). Deliberate non-penetrative sex without vaginal sex or deliberate oral sex without vaginal sex are also sometimes considered birth control. While this generally avoids pregnancy, pregnancy can still occur with intercrural sex and other forms of penis-near-vagina sex (genital rubbing and the penis exiting from anal intercourse) where sperm can be deposited near the entrance to the vagina and can travel along the vagina's lubricating fluids.


Lactation
The lactational amenorrhea method involves the use of a woman's natural postpartum infertility which occurs after delivery and may be extended by breastfeeding. This usually requires the presence of no periods, exclusively breastfeeding the infant and a child younger than six months. The World Health Organization states that if breastfeeding is the infant's only source of nutrition, the failure rate is 2% in the six months following delivery. Six uncontrolled studies of lactational amenorrhea method users found failure rates at 6 months postpartum between 0% and 7.5%. Failure rates increase to 4-7% at one year and 13% at two years. Feeding formula, pumping instead of nursing, the use of a pacifier, and feeding solids all increase its failure rate. In those who are exclusively breastfeeding, about 10% begin having periods before three months and 20% before six months. In those who are not breastfeeding, fertility may return four weeks after delivery.

Emergency
Emergency contraceptive methods are medications (sometimes misleadingly referred to as "morning-after pills") or devices used after unprotected sexual intercourse with the hope of preventing pregnancy. They work primarily by preventing ovulation or fertilization. A number of options exist, including high dose birth control pills, levonorgestrel, mifepristone, ulipristal and IUDs. Levonorgestrel pills, when used within 3 days, decrease the chance of pregnancy after a single episode of unprotected sex or condom failure by 70% (resulting in a pregnancy rate of 2.2%). Ulipristal, when used within 5 days, decreases the chance of pregnancy by about 85% (pregnancy rate 1.4%) and might be a little more effective than levonorgestrel. Mifepristone is also more effective than levonorgestrel while copper IUDs are the most effective method. IUDs can be inserted up to five days after intercourse and prevent about 99% of pregnancies after an episode of unprotected sex. This makes them the most effective form of emergency contraceptive. In those who are overweight or obese levonorgestrel is less effective and an IUD or ulipristal is recommended.
Providing emergency contraceptive pills to women in advance does not affect rates of sexually transmitted infections, condom use, pregnancy rates, or sexual risk-taking behavior. All methods have minimal side effects.

Dual protection
Dual protection is the use of methods that prevent both sexually transmitted infections and pregnancy. This can be with condoms either alone or along with another birth control method or by the avoidance of penetrative sex. If pregnancy is a high concern using two methods at the same time is reasonable and two forms of birth control is recommended in those taking the anti-acne drug isotretinoin, due to the high risk of birth defects if taken during pregnancy,