Fertile inventions: new contraceptive techniques.

Abstract

Research into contraception is producing new techniques that involve everything from vaccinations to nasal sprays. Steroids are the basis of the conventional contraceptive pill and much current research is on alternative ways of introducing the same drugs into the woman's reproductive system. Norplant is 1 approach. It involves implanting 6 tiny silicone-rubber tubes just beneath the skin of a woman's underarm. The tubes contain a drug, widely used as an ingredient of the contraceptive pill, which is slowly released from the tubes over a period of 5 years. It is understandable that much contraceptive research is focused on the womb. The brain, however, seems a strange place to be concerned with when trying to prevent conception. But it is the brain that controls a woman's ovulation by sending signals to the reproductive system via the pituitary gland. And now it is possible to synthesize chemicals which, when given in the form of a nasal spray, will inhibit ovulation by mimicking the brain's signals to the pituitary gland. It may even be possible to develop drugs which act directly on parts of the brain itself--a prospect we should be aware of, whether we would approve of it or not. There has been such an explosion of knowledge of the neural transmission systems that this may not be so far-fetched as it sounds. Research in China tends to concentrate more on naturally occurring substances--like a new form of female sterilization which involves not anesthetics or surgery but a substance called "mucilage"--1 of the ingredients of birds-nest soup. If mucilage is passed through the cervix into the fallopian tubes it causes them to block up and so prevents the passage of the ovum. There is a Western "high-tech" alternative to this, called methylcyanoacrylate--you might be more familiar with it as "superglue" or "crazy glue." Used carelessly it can stick your fingers together, but this tendency to join human tissues can be more productively used to block up the fallopian tubes. The Chinese are also looking at another natural substance as the basis of the possible "male pill." This is gossypol which occurs in cottonseed. A major reason why most research has been focused on contraception for women is that men present problems of quite a different order of magnitude. While a woman only ovulates once every 28 days or so, male sperm are produced continuously, with 200-400 million of them in each ejaculation. But drugs based on gossypol, which seems to have the effect of reducing the sperm count, may be the answer. Under the auspices of the World Health Organization, research on gossypol and other plants with contraceptive potential is now going on over all the world. Some 350 have been put under the microscope so far and about 30 look worth pursuing.