In the 50 years since it was first approved as a contraceptive, the pill has revolutionised women's lives, giving them more choices both in their roles in the family and the workplace.

 While contraception did of course exist prior to the pill, it was the responsibility of the man. Unwed lasses often could not finish school while those who were married had little say in the number of children they would have or in child spacing. Diaphragms and douches existed but were hardly reliable, making it difficult for women to hold on to a demanding career.

Liberation for the ladies came on May 9, 1960 when the first pill, Enovid 10mg, was approved by the US Food and Drug Administration. Since then, the pharmaceutical industry has worked continuously to develop and improve birth control.

According to Dr Phil Smits, head of Women's Healthcare Global Business Unit at Bayer Schering Pharma, 535 brands of the pill are now available, though only 78 products can be found in the Asia-Pacific region. The pill serves its duty as a contraceptive decisively, with 99.9 per cent of them effective and safe.

Recently Bayer, one of the leaders in the field, celebrated the pill's golden anniversary with an event in Beijing at which the documentary "The Pill that Changed the World" was screened.

Funded by Bayer, the movie, which shows here on July 25, traces the history of contraception, travelling back in time 4,000 years when the Egyptians used pomegranate seeds formed with wax as vaginal suppositories. Coincidentally, it was later discovered that the fruit contains natural oestrogen, a key female hormone used as a main ingredient in the modern contraceptive pill.

Throughout the one-hour documentary, viewers will be entertained by the various methods our ancestors have tried to keep unwanted pregnancies at bay, including crocodile dung pessaries and condoms made of animal gut, fish skin and linen.

Development of modern contraception methods started in the early 1900s when a German scientist discovered that menstruation is regulated by hormones and used extracts of synthetic hormones from animals and plants to produce his own contraceptives in 1910.

While the pill is hailed as one of the most important inventions of the last century, its ability to control fertility also gave rise to a heated debate about promiscuity, resulting in its being inaccessible to many women until the 1970s for religious reasons.

On the plus side, competition and a wider market have pushed pharmaceutical companies to add greater value to the pill, using hormones to help treat menstrual disorders, premenstrual syndrome (PMS), as well as cure acne and endometriosis.

In Asia, the pill is less popular than in other parts of the world when compared to other contraceptive methods due to religious and cultural beliefs as well as male dominance. In China alone, 13 million abortions are performed every year while pill for contraceptive use is only 1.5 per cent.

Part of the reason for low adherence to the pill when it is prescribed either for birth control or menstrual problems are the side effects. The women don't understand - and don't like - the weight gain, the increased melasma on their faces, or the lack of monthly bleeding.

In fact, each product has a different regimen and certain combinations help do away with symptoms. The 24/4 regimen, for example, can cure PMS and this year, Bayer is launching a new pill that will help deal with heavy menstrual bleeding. Approval from Thailand's FDA is awaited,

Women in Thailand are an exception to the Asian rule, with 30.9 per cent using the pill for birth control, according to the United Nation's Department of Economic and Social Affairs in 2009.

While Thai women can buy the pill from any pharmacy, experts recommend an initial medical consultation so that any health problems can be diagnosed before starting a course.

And what that often-mentioned male contraceptive pill? Will it ever be a reality?

Bayer did invest several years back in exploring the potential but have now stopped all projects.

"It's infinitely more difficulty to safely and effectively deal with millions of sperm," says Smits. "It's not a male conspiracy. It just can't be done."