Which contraceptives are most effective?

It is estimated that half of all pregnancies are unplanned, and that about half of those are due to contraceptive failure, usually as a result of incorrect use.

It is estimated that half of all pregnancies are unplanned, and that about half of those are due to contraceptive failure, usually as a result of incorrect use.

Researchers wanted to compare the effectiveness of long-acting reversible contraceptive methods (such as intrauterine devices [IUDs] and hormonal implants) with other commonly prescribed contraceptive methods (oral contraceptive pills, transdermal patches, contraceptive vaginal rings and progesterone injections). To do so, the researchers monitored a cohort of nearly 7,500 women for a period of up to three years.

Over the course of the study, 334 women had an unplanned pregnancy. The contraceptive failure rate among participants using the pill, patches or a vaginal ring was 4.55 per 100 participants followed for one year, compared with 0.27 among those using a long-acting reversible contraception method. A sexually active woman is therefore twenty times less likely to have an unplanned pregnancy if she is using an IUD or implant than if she is on the pill, wears patches or uses a ring. In addition, unintended pregnancy was twice as common among those who were under the age of 21 and used the pill, patches or a ring than it was among their older peers.

This study confirms that long-acting reversible contraceptive methods like IUDs are more effective than short-acting methods, mainly because they eliminate the risk of “forgetting” to use them. Many people incorrectly believe that IUDs can only be used by women who have already had children. There is also now a type of IUD that is not made of copper, but rather releases a low dose of hormones. One of the latter’s advantages is that it reduces the amount of bleeding and cramping during menstruation.

The www.sexualityandu.ca website, created by The Society of Obstetricians and Gynaecologists of Canada, is a reliable source of information on contraception.