The population in the world has been increasing exponentially since the World War II. There is now more than 6 billion people living on the world. It is estimated that about 356,000 babies are born around the world each day and 90% of whom are in developing countries. Demographers predict that by 2050, there will be 10 billion people on this planet.
Population explosion is depleting the Earth's finite natural resources including water, land and food. This will eventually overstress the ecosystem. At the same time, people produce all sorts of pollution as they consume the resources putting further pressure on the ecosystem. Overshooting the carrying capacity of the Earth puts many species under the threat of extinction. All these problems cannot be solved by the world's most advanced technology alone.
Apart from food supply and distribution of resources, social order is also exacerbated, especially in the developing countries. These countries will become poorer when they have to support huge populations. Thefts and riots will tend to rise.
On the whole, the standard of living will deteriorate if the population is over-sized. Before we run out of resources, immediate actions must be taken to limit the birth rate. Birth control has become a widespread practice because parents can give more to their children in small families. Therefore various mechanisms for birth control, known as contraceptive methods, exist. Here, we will introduce the common contraceptive methods used, from the past to the future.
In simple words, contraception is to prevent or interrupt the process of conception by intervening the processes of gamete production, fertilization and implantation.
There are various types of contraceptive methods involving different mechanisms. Chemical methods, such as contraceptive pills, work by action of hormonal interference so as to suppress ovulation. Physical methods involve the use of barrier to prevent sperms from fertilizing ova or even using surgical methods to cut and tie up the reproductive ducts. Some people prefer behavioural ones, including abstinence and rhythm/ natural method.
Most contraceptive methods can be used alone or, more commonly, combined with another method as in the case of condom and diaphragm which are lined with spermicide. Sometimes, a method can involve more than one mechanism of action. For example, combined pills work by suppressing ovulation, and at the same time, they provide a second defense mechanism to hinder sperm ascent by thickening cervical mucus. These raise the reliability of contraception.
Some societies in the past practiced abstinence by prohibiting sex during certain period of the month, such as when a woman was lactating or menstruating, and several religious festivals, like Lent and feast days. However, their existence was unlikely meant to be contraceptive method to begin with, but due to religious results. Even if they engaged in sexual activities, they sometimes practiced withdrawal in which they believed man's 'seed' could be prevented from entering woman's body. However, some religious groups condemned this as they considered it to be a sin for a man to waste his seed.
Apart from the above natural contraceptive methods, ancient people also depended on some artificial methods. They were found to use douches and drugs, and to insert vaginal suppositories (devices like IUD).
One of the best known methods of contraception was to use honey or olive oil in ancient Greece as an impediment to sperm motility. People also gathered gums from the acacia shrub which contained lactic acid which acted as contraceptive jelly.
The above methods were also practiced by ancient Egyptians, but they also used animal dung to be inserted into the vagina. This was proven to be less effective as some types of dung, like that of crocodiles, were found to be alkaline. This would neutralize the acidic environment of the vagina, thus providing an optimum condition for the sperms.
The most effective suppository contraceptive method in ancient time was probably the insertion of a sponge soaked in vinegar or wine into the vagina before copulation.
The contraceptive device regarded as the first modern one was the male condom appeared in the early 16th century. However, it was more than a pregnancy prevention measure, but a method to limit sexually transmitted diseases.
Abstinence is the only safe-fire method to avoid pregnancy, but it is only suitable for highly motivated couples. The menstrual cycle of a female can be divided into two phases, the fertile period and the safe period. The fertile period is when fertilization is the most likely to occur should mating take place. It is a period of five days before and after ovulation because sperms can survive up to five days in the uterus before they die. The remaining days in the cycle is called the safe period. A woman should only have sexual intercourse during the safe period if she is not ready to become pregnant. This calendar rhythm method is considered as the safest contraceptive method as it does not involve foreign objects or chemicals. However, it is not very reliable because the time of ovulation is difficult to predict as it is constantly influenced by tension, illness and stresses which contribute to its high failure rate. It has to be done with daily monitoring and long-term commitment. A woman may identify the time of ovulation by measuring her body temperature in the morning which may be slightly higher than normal just before ovulation. Some women also claim to experience regular abdominal pain, which is known as mittelschmerz, during ovulation.
Withdrawal is to remove the penis from the vagina just before ejaculation. It has a very high failure rate, 23%, but is definitely better than nothing. This is because the Cowper's glands of the male tend to secrete a clear fluid which contains sperms when he is sexually aroused. This means that sperms can still dribble from the penis to the vagina before orgasm. Another reason is that it is often a difference between intentions and actions. It is always difficult for a couple to separate before ejaculation due to physiological and psychological reasons.
There are mainly two kinds of pills: the combined pill and the mini-pill. The combined pills contain synthetic compounds similar to estrogen and progesterone. The pills are taken for three continuous weeks daily to prevent conception, and stopped for a week for menstruation to take place. The pills prevent the secretion of follicle-stimulating hormone (FSH) and lutenizing hormone (LH), thus inhibiting follicle development and ovulation.
The mini-pills contain progesterone only. The pills are taken daily without stopping. They can thicken the mucus in the cervix, hence forbidding sperms from moving up to the uterus.
Although taking combined pills is an effective contraceptive method, it has some side effects. It is believed that combined pills may cause headaches, increase the risk of cardiovascular diseases and uterus cancer. The risk increases with age, fatness and smoking. Therefore, it is advised that women over 35 years old should take mini-pills. Although they are less effective, they have fewer side effects.
Injectables can be divided into two types, progestin-only and combined progestin and estrogen, which can be used as an alternative to the oral contraceptive pills. Both types of injectables are applied regularly at a constant dose each time, depending on individual brand. Chemicals are injected into the muscle tissue without prior massaging in the first seven days of the menstrual cycle.
This method is effective with a failure rate of 1% and reversible. However, it may lead to irregular menstrual patterns.
Implants, known as Norplant, consist of six flexible capsules, each of the size of a match, to be placed under the skin of a female's upper arm by a small surgery. The most preferable time for inserting the implants is when a woman is menstruating. The capsules release crystalline form levonorgestrel, which is a type of progestin, in a period of 5 years. New capsules can be inserted to replace the olds if no excess allergy is observed. The method is highly effective, with a failure rate of 0.2%, reversible and does not cause cardiovascular complaints as it is estrogen-free. The only major disadvantage is that it is comparatively expensive as it involves a surgery.
These are chemicals which are used to kill or immobilize sperms deposited in the vagina thus preventing them from fertilizing the ovum. Most of the spermicides work by disrupting the integrity of the sperm membrane. They may exist in the forms of foam, jelly, tablets or suppository and are often used together with other types of contraceptive methods. It is also discovered that spermicides can sometimes prevent transmission of diseases like syphilis, herpes, hepatitis B, and even HIV.
The use of condom, a piece of thin rubber, is the most common contraceptive method due to its convenience. It can simply be pulled over the erect penis before a sexual intercourse. It prevents ejaculated sperms from entering the vagina and so fertilization cannot occur. Some condoms are lubricated and contain spermicide. It is quite reliable and has no side effects. Another important use of condom is to prevent transmission of sexually transmitted diseases.
It can be regarded as a condom for the female as its working principles are similar to that of a condom. A diaphragm is a piece of shallow rubber with a flexible rim. It is inserted into the vagina over the cervix of a female and is left there. It prevents sperms from entering the vagina to fertilize the ovum.
If a woman does not want to have a baby for a longer period, she can ask a doctor to insert an IUD, which is a piece of plastic ring or cooper spiral, into her uterus. It can prevent a zygote from implanting in the uterine wall. It can be left in the uterus for at most 2 years until the woman wants to get pregnant. However, it may hurt and cause irritation to the uterus, and may even cause infertility.
Douching, that is to rinse the vagina with a chemical after an intercourse. The chemical is often acidic because acidic solutions can in fact kill sperms and prevent them from fertilizing an ovum. However, it is not very reliable as sperms can move past the cervix in ninety seconds after an intercourse, and the chemical cannot reach them.
After unprotected intercourse, something can be done to terminate pregnancy. This is achieved by taking two tablets of heavy dose combined pills within 72 hours of intercourse, preferably within one day. However, it may bring about side effects such as nausea and vomiting. Another method is to insert a copper IUD within 5 days after sex. It is better than taking pills because it avoids the side effects and can continue to prevent the women from pregnancy. The above methods aim to prevent implantation.
It is a permanent method to prevent conception in both male and female. It involves a simple operation to cut and tie the reproductive tubules. In man, the operation is called vasectomy. It is to cut and tie the vas deferens (sperm ducts) to prevent sperm from moving into the urethra. A man can ejaculate even after vasectomy, but with no sperms in the semen. The semen contains only secretions from the prostate gland and seminal vesicles. Also, it will not hinder the development of sexual characteristics because testosterone can still be passed around the body.
In female, the operation is called tubal ligation. It involves cutting and tying of oviducts so that sperms cannot fertilize the ovum as no ova can move down the oviducts into the uterus. As the operation is usually irreversible, operated people wanting to get pregnant later will not try it.
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An ideal contraceptive method should be effective, convenient, coitally independent and reversible. Research has been going on to develop such a contraceptive method. Hormonal suppression of sperm production and chemical disturbance at the sites of sperm production are going to be the new trend of development. Chemicals are investigated to suppress luteinizing hormone (LH) and follicle stimulating hormone (FSH) which are responsible for sperm production. Two implants are now undergoing clinical trials which release an agonistic of the luteinizing hormone releasing hormone (LHRH), thus suppress sperm formation. However, as testosterone production is also suppressed, the male sex characteristic will be affected. A synthetic androgen must be given to counter this.
Antifertility vaccines, which neutralize hormones responsible for sperm production or maturation, are also under investigation. The vaccines are accompanied by synthetic androgen required for sex drive and behavior in male. For females, vaccines against human chorionic gonadotropin and other sex hormone, sperm antigens and ovum antigens are all being tested.
Research is done on plant extracts which are known for their antifertility effect on male. One of which is gossypol found in cotton plant which inhibits an enzyme responsible for the metabolism of sperm. Its effect was recognized when it was discovered that area where the plant is grown has extremely low birth rate.
Physical intervention involving injection of a polymer called styrene maleic anhydride into the vas deferens to block the passage of sperms is under trials. The barrier can be later on dissolved by injecting dimethyl sulphoxide, making the procedure reversible. Another new development is the intravaginal ring for female. It is designed to release hormones, either progestin alone, or with estrogen, to act in the same ways as the contraceptive pills. Users can easily place the ring and remove it. The levonorgestrel ring was developed to be worn around the cervix and is able to release a synthetic progestin. This hormone makes the cervical mucus impregnable to sperms. It can be inserted in place for three months and is removed during menstruation. It can then be reinserted afterwards.
Effectiveness is described by the method's ability to prevent contraception and is often expressed by its failure rate. There are two components, namely theoretical effectiveness and use effectiveness.
Theoretical effectiveness applies to those who follow instructions carefully and use correctly. This requires dedicated participation of the users. It is a measure of biological effectiveness under ideal circumstances.
Use effectiveness refers to a measure of reliability among a large group of users who may sometimes omit or discontinue application. This also includes errors.
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Almost every type of contraceptive method had undergone clinical trials to study its side effects before it appears on the market because there are so many users utilizing the contraceptive methods for long period of time which are with potential complication. Therefore it is essential to understand the risks and benefits of each contraceptive method before use.
The methods' ability to prevent sexually transmitted diseases (STDs) should also be taken into consideration. It is known that condoms can lower the risk of being infected by STDs and hence are welcomed by many couples.
Different types of contraceptive methods have their own shortcomings and people should avoid using the one with undesirable side effects. However, none of the mentioned contraceptive methods is as dangerous as a full-time pregnancy.
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No method can be used effectively if the user dislikes it. Therefore it is important to assess one's preference carefully in selecting a contraceptive method. People who forget to take pills or put on physical barriers constantly should consider choosing a more permanent method. Those who are conscience and have good memory can use natural family planning method as it has the least potential danger. Someone may be allergic to rubber and condom is certainly not his / her desired method. Also, the individual's age, personality, physical characters, belief and the cost of the methods influence one's choice.
It should be noted that no contraceptive methods are perfectly effective in preventing contraception. The failure rate depends on the individuals, physiologically and psychologically, and it tends to increase with time. When choosing a method of contraception, besides effectiveness, its side effects, disease prevention ability and personal preference should be taken into consideration.
Apart from all sorts of contraceptive methods available, the problems cannot be alleviated without education because birth control is largely dependent on the self-discipline of every individual. People should be taught that the significance of contraception is not just to lessen the population, but it also play an important role in saving life and ensuring better health of mothers and children, thus contributes to a better society. It is because death resulting from pregnancy, nearly 600,000 each year, and inadequate care in childbirth due to poor technology and unhygienic environment can be largely reduced. This will also improve the physical and mental health of children everywhere. These can be achieved by providing family planning consultation and materials. At the same time, the health of mother and child must be improved by careful diagnosis.