[Biology Class Notes] on Contraception Pdf

The definition of contraception in human physiology could be described as birth control through the deliberate prevention of conception or impregnation.

The link between pregnancy and a man’s semen u was not clearly understood in ancient times. The earliest contraceptive methods involved preventing semen from entering a woman’s uterus. Coitus interruptus or withdrawal of the penis before ejaculation has been one of the oldest methods, and although it is not reliable but is still widely practised. 

Manuscripts surviving from ancient Egypt record various methods for averting conception. A detailed account of the contraceptive method can be found in the works of Soranus of Ephesus (dated 2nd century CE). For all practical purposes, the education of the general populace on the subject of contraception was not initiated until the early 1800s. The first systematic work in contraception began in 1882 by Dr Aletta Jacobs.

In the late 19th century a better understanding of reproductive anatomy led to the widespread use of devices and methods of varying risk and reliability. Sterilization is one of the most effective forms of contraception. The method is permanent and generally irreversible.

The most effective of the reversible methods are hormonal contraceptives i.e. birth control pills, Norplant, and Depo-Provera, intrauterine devices (IUDs), and condoms used with spermicide. Each of these methods and devices has a potential success rate of approximately 99% if used consistently and correctly. Many methods of contraception involve secondary health risks. The safest contraceptive methods include the usage of barrier devices and avoiding sexual intercourse during the ovulation period.

Some of the most affordable and widely available contraceptive methods are too ineffective to be practical. Spermicides in the form of cream foam or jelly, are only about 80% effective when used without any type of barrier. Cleaning with water or with any spermicidal agent only affects the sperm that remain in the vaginal canal. The sperm that has entered the uterus is not affected. Coitus interruptus, or withdrawal, does not take into account drops of seminal fluid that’s released before ejaculation. Breast-feeding inhibits ovulation but is not reliable enough to be effective.

What is the Meaning of Contraception?

Contraception can be explained as the usage of artificial methods or other techniques to prevent pregnancy as a consequence of sexual intercourse. The major forms are barrier methods (usage of condoms or sheaths), using a contraceptive pill (containing synesthetic sex hormones which can prevent ovulation in females, IUDs or intrauterine devices (such as the coil, which prevent a fertilized ovum from implanting in the uterus) and finally, male and female sterilization.

Types of Contraception

There are 5 main types of contraception but all are not appropriate for all situations. An appropriate method of birth control depends on an individual’s overall health, age, number of sexual partners, frequency of sexual activity, and family history regarding certain diseases. The classification of contraceptive methods are mentioned below:

1. Short-acting Hormonal Methods: Hormonal methods of birth control use hormones to regulate or stop ovulation and prevent pregnancy. Ovulation is the biological process in which the ovary releases an egg, making it available for fertilisation. 

Artificial hormones can be introduced into the body via pills, injections, skin patches, vaginal rings, transdermal gels, implantable rods, and intrauterine systems.

• Progestin-only pills (POPs): It can be categorised under oral contraceptives. A woman can take one pill daily, preferably at the same time each day. POPs may interfere with sperm function or with ovulation. These pills thicken cervical mucus, making it difficult for sperm to swim into the uterus or enter into the fallopian tube. POPs can alter the normal cyclical changes in the uterine lining and lead to unscheduled or breakthrough bleeding. These hormones do not appear to be associated with an increased risk of blood clots.

• Injectable Birth Control:  This method involves an injection of a progestin, depot medroxyprogesterone acetate

• DMPA

• DMPA) in the arm or buttocks once every 3 months. However, it can cause a temporary loss of bone density, particularly in adolescents. Those using injectable birth control should eat a diet rich in calcium and vitamin D or take vitamin supplements to combat the side effects of the contraceptive.

• Combined Oral Contraceptives/ COCs: COCs contain synthetic oestrogen and progestin, which functions to inhibit ovulation. It functions similarly like progestin-only pills.

• Vaginal Rings: Another one of the safest contraceptive methods is the usage of the vaginal ring. It is thin, flexible, and approximately 2-inches in diameter. It delivers a combination of Ethinyl estradiol and a progestin. The ring is inserted into the vagina, where it releases hormones continuously for 3 weeks. The woman removes it for the 4th week and reinserts a new vaginal ring 7 days later. The risks for this method of contraception are similar to those for the combined oral contraceptive pills. It may not be recommended for women with certain health conditions, including high blood pressure, heart disease, or certain types of cancer.

2. Barrier Methods: Specially designed barriers are made to prevent sperm from entering the uterus, and are removable and may be an option for women who cannot use hormonal methods of contraception. 

• Male Condoms: This condom is a thin sheath that covers the penis to collect sperm and prevent it from entering the woman’s uterus. It is one of the safest birth control methods. Male condoms are generally made using latex or polyurethane. However, a natural alternative is a lambskin (made from the intestinal membrane of lambs). 

• Latex or polyurethane condoms reduce the risk of spreading sexually transmitted diseases (STDs) which Lambskin condoms do not do. The condoms are disposed of after a single-use.

• Female Condoms: These condoms are thin, flexible plastic pouches. A part of the condom is inserted into a woman’s vagina before intercourse to prevent sperm from entering the uterus. The female condom reduces the chances of contracting STDs and are disposed of after a single-use.

• Diaphragms: Each diaphragm is a shallow, flexible cup made from latex and is inserted into the vagina before intercourse. It blocks the sperm from entering the uterus. Spermicidal cream should be used with a diaphragm and it should remain in place for 6-8 hours after intercourse to prevent pregnancy, but should be removed within 24 hours. 

Women also need to be measured for a new diaphragm after giving birth, having pelvic surgery, or gaining or losing more than 15 pounds.

3. Emergency Contraception: Emergency contraception can be used after unprotected intercourse or if a condom breaks.

• Copper IUD: The copper IUD is an effective method of emergency contraception. The device can be inserted within 120 hours of unprotected intercourse. The method is almost 100% effective at preventing pregnancy as long as the device remains in place. And there are no issues related to weight or obesity associated with the effectiveness of the method.

• Emergency Contraceptive Pills (ECPs): ECPs are hormonal pills, taken either as a single dose or two doses 12 hours apart. These pills are intended for use in the event of unprotected intercourse. If they are taken before ovulation, the pills can delay or inhibit ovulation for at least 5 days to allow the sperm to become inactive. They can also thicken cervical mucus and may interfere with sperm function. ECP pills should be taken as soon as possible after semen exposure but should not be used as a regular contraceptive method. 

4. Intrauterine Methods: An intrauterine device (IUD) or an intrauterine system (IUS), is a small, T-shaped device inserted into the uterus to prevent pregnancy. The device can remain in place and function effectively for many years at a time. After a certain period, or when the woman no longer needs or desires contraception, the device can be removed.

5. Hormonal IUD or IUS: It releases a progestin hormone (levonorgestrel) into the uterus. The hormone causes the cervical mucus to thicken which inhibits sperm from reaching or fertilising the egg. It may prevent the ovaries from releasing eggs as well. The failure rate of a hormonal IUS is less than 1%; however, a small percentage of women may experience expulsion of the device and have to have it reinserted.3 Some research also suggests that these IUDs maintain their effectiveness up to a year beyond their recommended use period.4 This method may also be used to treat heavy menstrual bleeding because the hormone often reduces or eliminates uterine bleeding.

6. Sterilisation: It is a permanent form of birth control that either prevents a man from releasing sperm or a woman from getting pregnant. These procedures usually are not reversible.

• Vasectomy: It is a surgical procedure that cuts, blocks or closes the vas deferens. It blocks the path between the testes and the urethra. The sperm cannot leave the testes and therefore cannot reach the egg. It can take approximately three months for the procedure to be completely effective

• Tubal Ligation: Tubal ligation is a surgical procedure in which the fallopian tubes are cut, tied, or sealed. It blocks the path between the ovaries and the uterus. 

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Myths about Birth Control

Birth control myths have endured throughout history, but science has disproved some of the most common misconceptions.

• You can not get pregnant while on your period: It is incorrect to believe that a woman cannot become pregnant when on her period. Although women may be less fertile in the first few days of menstruation, pregnancy is still possible because sperm can survive for several days inside the female body.

• If you have intercourse in a hot tub, you cannot become pregnant: Pregnancy is not prevented by sexual intercourse in a hot tub or pool. Furthermore, there is no sexual position that will prevent you from becoming pregnant.

• It is safe to have sex without penetration, ejaculation, or orgasm: Even if the father does not ejaculate, the woman can become pregnant. When the penis or sperm penetrates the vagina, pregnancy is possible. A woman can become pregnant whether or not she has an orgasm or is in love with the man.