Science News Archive

Spray on Contraceptives

The world’s first female contraceptive spray will begin trials in Australia next year. The idea behind the spray is to reduce the doses of contraceptive needed to be effective and to deliver a steady supply of the drug- a synthetic version of the sex hormone progestin. One of the problems with the oral contraceptive or pill, is that the concentration of the hormone in the body peaks after taking the pill and drops off very rapidly, so that women need to take the pill at the same time each day to make sure the levels of progestin stay high enough to be effective. The pill also needs to pack quite a high dose of hormone to maintain high enough levels in the blood for 24 hours. The contraceptive spray behaves in a similar way to water-resistant sunscreens, which modify the structure of the outer layer of skin allowing the chemicals to penetrate. Once under the skin the hormone collects in a reservoir and then slowly and steadily defuses into the bloodstream. By using lower concentrations of hormone in the spray, it should hopefully reduce the various possible side effects that are associated with taking the pill. Breast feeding women could also use it knowing that any hormone that was secreted into milk would be broken down in their baby’s gut.

7th Dec 2003