12th Class Biology Blank Methods of Birth Control

Meaning : The regulation of conception by preventive methods or devices to limit the number of offspring  is called birth control.

Methods : A variety of methods are known for birth control. The birth control methods which deliberately prevent fertilization are referred to as contraception. These methods are of 2 main types : temporary and permanent.

(1) Temporary  Methods : These  are  further  of  many types :

(i) Safe Period (Rhythm Methods) : A week before and a week after menses is considered the safe period for sexual intercourse. The idea is based on the following facts-

(a) Ovulation occurs on about the 14^th day (may be 13 ^th to 16^th day) of menstruation.

(b) Ovum survives for about 1-2 days.

(c) Sperms remain alive for about 3 days.

This method may reduce the chances of pregnancy by about 80 percent. However, a great care is needed in its use. Rhythm method is also called natural family planning. i.e., a few days before and a few days after ovulation. Changes in cervical mucus and body temperature during the menstrual cycle mark the ovulation time. Thus, the natural family planning requires adequate knowledge of these physiological signs. Some couples use the natural family planning method of increase the chances of conception so that unplanned pregnancies are avoided.

(ii) Coitus Interruptus : This is the oldest method of birth control. It was in use over 2,000 years ago. It involves withdrawal of the penis from the vagina by the male before ejaculation so that semen is not deposited in the vagina and there is no fertilization.

(iii) Spermicides : Foam, tablets, jellies, pastes and creams, if introduced into the vagina before sexual intercourse, adhere to the mucous membrane and immobilise and kill the sperms. These contain seprmicides such as lactic acid, citric acid, boric acid, potassium permanganate and Zinc sulphate.

(iv) Mechanical Means : These are of 3 types :

(a) Condom (Nirodh) is a thin sheath, usually made of rubber, to cover the erect penis. It is the most widely used contraceptive by males in India as it is cheap and easily available. It is given free also by government. It checks pregnancy by preventing deposition of semen in the vagina. Condom is also a safeguard against infection of AIDS and sexual diseases.

(b) Diaphragm and cervical cap are dome-shaped rubber plastic covers that are fitted on the cervix in the female's vagina, and check the entry of sperms into the uterus. These must be kept fitted for at least six hours after sexual intercourse. They are smeared with a spermicidal jelly or cream each time they are used. The diapharm and cervical cap are the counterparts of condoms in the female

(c) Intrauterine devices (IUDs) are plastic or metal object placed in the uterus by a doctor. These include loop, copper-T, spiral, ring, bow, shield, etc. They prevent the fertilization of the egg or implantation of the embryo. Their presence perhaps acts as a minor irritant and this makes the egg to move down the Fallopian tubes and uterus rather quickly before fertilization or implantation. Drawbacks of IUDs include their spontaneous expulsion, even without the woman's knowledge; occasional haemorrhage; perforation of uterus; tubal pregnancy (implantation of the embryo) in the oviduct; and chance of infection. Use of mechanical contraceptives have pregnancy rates of less than 10%.

(v) Physiological (Oral) Devices :  Birth control pills (oral contraceptives) check ovulation by inhibiting the secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) that are necessary for ovulation. Hence, no eggs are released in a woman on the pill and conception cannot occur. The birth control pills have side effects such as nausea, breast tenderness, weight gain and break-through bleeding (slight blood loss between menstrual periods) and high blood pressure.  Pill Mala D is taken daily, and the pill Saheli is taken weekly. Oral contraceptives have pregnancy rates less than 1%. Birth control pills are likely to cause cardiovascular problems.

(vi) Other Contraceptives : Certain contraceptives, such as progestin minipill, are implanted under the skin of the upper arm. They prevent pregnancy for 3 to 4 years. They steadily release a tiny amount of progestin into the blood. Injectable one- month contraceptives are made in Germany, Maxico and China. These are marketed to many countries.

(vii) Abortion : Abortion is the medical termination of pregnancy (MTP) before the foetus becomes viable. It is one of the most widely used methods of fertility control in world. Certain pills act as abortants. They function by inducing menstruation which checks the implantation of the zygote or detaches the implanted egg. There are movements against abortion practically all over the world. A drug named RU-486, an analogue of progesterone, developed in France terminates pregnancy within the first few weeks. It blocks the progesterone receptors in the uterus, thereby preventing progesterone from maintaining pregnancy.

(viii) Abstinence : The best and 100% reliable way to avoid conception is to abstain from sexual intercourse. It is an unnatural mode of birth control, and seems impracticable. Some couples practice abstinence at certain times with success.

(2) Permanent Method : Sterilization provides a permanent  and sure birth control. It is called vasectomy in man and tubectomy in woman. It involves the removal of a short segment of each vas deferens or oviduct and tying up of the remaining ends tightly with surgical thread. The operations are minor, usually performed under local anesthesia, give very little discomfort, and do not affect the sexual life.

(i) Laparoscopy : Now a telescopic instrument called laparoscope is used in tubal ligation.  This blocks the fallopian tubes. Eggs continues to be produced because the ovaries are intact, but they fail to pass into the uterus and sperms fail to reach the eggs for fertilization.

(ii) Most Effective Birth Control : Sterilization is at present the most effective means of birth control. It is difficult to reverse.

(iii) Extent of Contraceptive Use : According to a UN report in the Tribune dated 24.8.87, half of the world couples use contraception and one in three chooses, sterilization.

(iv) Medical Advice : The birth control measures should be used with the guidance of qualified doctors. The government provides these facilities free at the family planning centres. Contraceptives are given free or at nominal prices at these centres to the couples of reproductive age desirous of preventing conception.

(v) Advice for Fertility : The couples who are not getting children can also seek advice and remedy at the family planning centres.

(vi) Abortion or Medical Termination Pregnancy (MTP) has now been legalised in India.

Method of Birth Control