02 April 2014

#120 Method of birth control

There are 4 main groups of birth control methods: natural, chemical, mechanical and  surgical. 

1. Natural methods

2. Chemical methods

3. Mechanical methods

4. Surgical methods

Photos from WebMD:

Chemical methods
Birth Control Pill
The most common type of birth control pill uses the hormones
 estrogen and progestin to prevent ovulation. 
When taken on schedule, the pill is highly effective.
 About 8% of typical users get pregnant,
 including those who miss doses. 
Like all hormonal contraceptives,
 the pill requires a prescription.

Spermicide contains a chemical that kills sperm. 
It comes in the form of foam, jelly, cream, or film 
that is placed inside the vagina before sex. 

Mechanical methods

Male Condom
The latex condom is the classic barrier method. 
It prevents sperm from entering the woman’s body, 
protecting against pregnancy and STDs. 
Of couples who rely only on male condoms, 
15% get pregnant in a year.

Female Condom
The female condom is a thin plastic pouch that lines the vagina 
and can be put in place up to 8 hours before sex. 
Users grasp a flexible, plastic ring at the closed end to guide it into position. 
It's somewhat less effective than the male condom.

The diaphragm is a rubber dome that is placed
 over the cervix before sex.

IUD stands for intrauterine device, a T-shaped piece of plastic 
that is placed inside the uterus by a doctor. 
The copper IUD, ParaGard, works for as long as 12 years. 
The hormonal IUD, Mirena, must be replaced after 5 years. 
Both types make it more difficult for sperm to fertilize the egg. 
Fewer than eight in 1,000 women get pregnant.

Surgical methods

Tubal Ligation 
A surgeon closes off the fallopian tubes, preventing eggs 
from making their journey out of the ovaries.  

Besides condoms, a vasectomy is the only birth control option available to men. It involves surgically closing the vas deferens – the tubes that 
carry sperm from the testes, through the reproductive system. 
This prevents the release of sperm but doesn’t interfere with ejaculation.

Least Effective Methods
Without using any form of birth control, 
85% of sexually active couples will get pregnant within a year. 
Even the least effective birth control options
 reduce that number considerably.

Source: Letts Revise IGCSE - Biology:Complete Study and Revision Guide

Slide Show Birth control Options from WebMD:


17 Effects of Birth Control on the body from HealthLine (not included in the syllabus):


  1. maggie.danhakl@healthline.comJanuary 13, 2015 at 1:39 PM


    I thought you might find this interesting. Healthline has compiled a list of the Effects of Birth Control in a visual graphic and I thought you and your readers would be interested in seeing the information.

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    If you think this information is a good fit for your audience would you share it on your site, http://igbiologyy.blogspot.com/2014/04/145-methods-of-birth-control.html , or social media?

    Let me know what you think and have a great week.

    All the best,
    Maggie Danhakl • Assistant Marketing Manager
    p: 415-281-3100 f: 415-281-3199

    Healthline • The Power of Intelligent Health
    660 Third Street, San Francisco, CA 94107
    www.healthline.com | @Healthline | @HealthlineCorp

  2. There is a mistake where it says contraceptive pills prevent pregnancy - surely oestrogen and progesterone can't prevent it because they are the causes of pregnancy.

    1. "Birth control pills prevent pregnancy through several mechanisms, mainly by stopping ovulation. If no egg is released, there is nothing to be fertilized by sperm, and the woman cannot get pregnant. Most birth control pills contain synthetic forms of two female hormones: estrogen and progestin. These synthetic hormones stabilize a woman's natural hormone levels, and prevent estrogen from peaking mid-cycle. Without the estrogen bump, the pituitary gland does not release other hormones that normally cause the ovaries to release mature eggs.".
      More information on Go Ask Alice! http://goaskalice.columbia.edu/how-do-birth-control-pills-work