By Ross Walker

With the burgeoning world population, the need to prevent pregnancies has become an increasingly discussed topic. The recent Dan Brown novel and subsequent movie, Inferno, was interestingly all around this topic, albeit the villain’s solution was somewhat too drastic. It is my opinion that for long-term sustainability of our resources and environment, the world can only cope with around four billion people. At present, we are approaching eight billion. Any visit to an intensely populated city is evidence that our current population growth is unsustainable.

So, regardless of your own personal view, I believe it’s time we all adopted a less self-centred worldview to responsibly contribute to better control the world’s population through prevention of pregnancy. The real solution here which, unfortunately, will be unpalatable for many people, is for only financially viable couples in long-term relationships – who only desire to have a small family – to be the ones becoming pregnant.

So, to quote the excellent New South Wales Family Planning Association website, I would like to give a brief overview of available methods of contraception, and their assessment of what information we should consider when accessing it.

1) The proven effectiveness of the method

2) Health issues which the person considering contraception may suffer that may limit particular choices

3) The ease-of-use

4) Potential side-effects of the method of contraception

5) All the alternatives available to the person

6) Reversibility

7) Protection against sexually transmitted infections

Contraception is divided into reversible and irreversible techniques. The most effective is the “fit and forget” long acting, reversible contraceptives which include IUDs and contraceptive implants. They are suitable for any age and have no contraindications to people with other health issues. They are easily removed and promptly reversible but you require a health professional to supervise and perform the implantation. There is also no protection against sexually transmitted infections. These are over 99% effective.

The Implanon subcutaneous contraceptive device is close to 100% effective and lasts for three years. The intrauterine devices last for around five years.

For those people who would prefer more short-term solutions, there is a depot injection of a form of progesterone, which can be given every 12 weeks. This is also highly effective.

Apart from condoms, the most commonly used form of contraception is the oral contraceptives pill, the minipill and the NuvaRing. The NuvaRing is inserted vaginally by the woman and replaced every three weeks.

At this stage, the only commercially available reversible contraceptive device for males is a condom, which has somewhere between 80 to 98% effectiveness depending on how carefully it is used. There is also a female condom which has a similar effectiveness rate and, of course, the diaphragm, which is somewhere between 88 to 94% effective. Condoms also offer protection against sexually transmitted infections.

Interestingly, a very effective form of contraception is breastfeeding, which is around 98% effective if the woman has given birth in the previous six months, is still not having periods and is fully breastfeeding.

The other less effective methods are fertility awareness based methods, which include the rhythm and temperature methods, which are over 75% effective, and the commonly used withdrawal method, which ranges in effectiveness of between 78 to 97%.

Emergency contraception, the so-called morning after pill, can be taken up to five days after unprotected sex but it is most effective within the first 24 hours.

Reversible contraception includes tubal ligation for a female and vasectomy for males. There is the potential for reversal but this requires re-operation and is not highly successful. Both of these forms of contraception are around 99.5% effective.

Apart from condoms and vasectomy, there have been numerous attempts over the years to discover an effective male contraception. Until now, hormonal manipulation, such as used with the oral contraceptive pill for females, has been disappointing and rather difficult to achieve. Other methods have looked at reducing sperm production in the testicles, preventing the sperm fertilising the egg and targeting the sperm’s ability to swim. These techniques have shown reasonable promise. Another interesting approach is what is known as the “clean sheet method” which allows orgasm but not ejaculation. This affects some of the muscles that are involved in ejaculation.

Probably the most interesting and recently researched area is using a polymer gel known as VasalGel. This gel is injected directly into the vas deferens under local anaesthetic. The vas deferens is the tube that connects the testicles to the prostate gland. The gel blocks the flow of sperm through the vas deferens and has been coined a “reversible vasectomy”. This creates a 2cm barrier in the vas deferens and therefore the sperm cannot get through. It has been trialled in rabbits and has been shown to be reversible after two years. A recent study in 16 monkeys showed it was 100% effective in preventing pregnancy. Interestingly, in a similar environment, fertile monkeys mating with mature female monkeys showed an 80% percent pregnancy rate. The complication rate of VasalGel was minimal. Standard vasectomy has around a 30% rate of what is known as sperm granulomas, which was only 3% with VasalGel.

The development of effective male contraception, in my view, is a welcome innovation and should be encouraged. Always the concern with males is firstly whether they are prepared to go through this minor procedure, and secondly, whether they would be honest with new partners about whether they had pursued male contraception. Regardless, we all really need to start becoming more aware of the human footprint on this planet and effective, viable means of reducing the world’s population. If we don’t, we will be seeing a very different world over the next 50-100 years.