Unwanted pregnancy warning: birth control effectiveness overestimated

Lianzi Fields
Thursday, May 3, 2012
birth control
Image: Thinkstock

A new report published in the American Journal of Obstetrics and Gynecology has revealed that nearly half of all women in the US overestimate the effectiveness of condoms and the pill to prevent unwanted pregnancies.

Researchers at Washington University School of Medicine in St. Louis, Missouri surveyed 4,144 women, finding that 45 per cent depended on these contraceptives as fail-proof methods of birth control.

Intra Uterine Device (IUD)

Other forms of contraception, including vaginal rings, birth control patches and injections, were also relied on far too heavily by most women, the researchers found.

Dr. David L. Eisenberg who led the study told Reuters Health: "We need to do a better job of educating the public -- women and men -- on the failure rates with typical use."

The problem with condoms and the pill is that both of these methods rely on perfect use. When women "typically used" these contraceptives, it was found that nine per cent of pill users still fell pregnant, while that figure jumped to between 18 and 21 per cent for condom users.

The most effective forms of birth control are intrauterine devices (IUD) and contraceptive implants, Eisenberg said, but even these are not 100 per cent fail-proof.

With both of these contraceptives, a doctor implants small matchstick-sized devices, which slowly release controlled amounts of the hormone progestin to stop unwanted pregnancies over several years.

IUDs are implanted in the uterus, and contraceptive implants are placed under the skin in a woman's arm. Both are reversible.

But even using these methods, women are still estimated to have a 0.2 to 0.8 per cent chance of becoming pregnant while using an IUD, and a 0.05 per cent chance with a contraceptive implant.

Contraceptive implants: Implanon

Eisenberg also said that better education needs to be extended to doctors who are not familiar or comfortable recommending or administering IUDs and contraceptive implants based on safety concerns.

A recent survey by the U.S. Centers for Disease Control and Prevention (CDC) confirmed that 30 per cent of health professionals in the US are still worried that IUDs may jeopardise the fertility of women who have never given birth.

"There are a lot of myths and misconceptions about which women are candidates," said Eisenberg, who believes that IUDs and implants should be the "default" option for women who want reversible forms of birth control.

But the cost of these contraceptives is still an obstacle for many women, with some of the most common products, such as the Implanon sub-dermal implant and the Mirena IUD costing between $400 and $800, on top of doctor's fees.

For women who spend between $10 and $50 a month on the pill and who do not have health insurance coverage, these alternatives may simply not be an option.

Watch: Contraceptives

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