Magazine article Clinical Psychiatry News

Obesity Raises Contraceptive Concerns in Teens

Magazine article Clinical Psychiatry News

Obesity Raises Contraceptive Concerns in Teens

Article excerpt


ORLANDO -- Data on how obesity affects contraceptive efficacy in adolescents are limited, but the consensus is that if efficacy is reduced, it isn't by enough to make a difference, according to Dr. Alene Toulany.

The effect of obesity is likely to be small, and studies of pharmacokinetics in obesity show that body weight accounts for 10%-20% of the variability of hormone levels, Dr. Toulany said at the North American Society for Pediatric and Adolescent Gynecology annual meeting.

"This is within the normal range for individuals who are not obese," she said.

Obesity increases the metabolic rate, increases clearance of hepatically metabolized drugs, increases circulating blood volume, and affects the absorption of contraceptive steroids through the adipose tissue, she said, so "the serum drug levels may be insufficient to maintain contraceptive effects, but the data are very limited."

The rate of adolescent obesity has quadrupled in the last 3 decades, from 5% among those aged 12-19 years in 1980 to more than 20% now. A third are currently overweight or obese. Sexually active obese women, regardless of age, are significantly less likely to use contraception, and obese teens are more likely to engage in risky sexual behaviors than are nonobese teens, said Dr. Toulany, an adolescent medicine specialist at the Hospital for Sick Children, Toronto.

So it is important to find the most effective contraceptive method, accounting for other risk factors and the likelihood of compliance, she said, noting that obesity is an independent risk factor for venous thromboembolism (VTE) and that studies suggest the risk is additive in users of estrogen-containing contraceptives.

But the benefits outweigh the risks of pregnancy in obesity--especially of unintended pregnancy, she said. The absolute risk of VTE in healthy women of reproductive age is small, and in adolescents it's even smaller, she added. "The presence of risk factors for VTE should be taken into account when we see these youth in our clinics, but we can and should offer estrogen-containing contraceptives as long as there are no other risk factors."

Contraceptive options in young obese patients include:

* Intrauterine devices. There is no evidence that copper IUDs or progestin-releasing IUDs have reduced efficacy in obese adolescents.

* Implants. These are highly effective, and although the concentrations may be 30%-60% lower in obese women, they remain above the contraceptive threshold for at least the first 3 years, Dr. …

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