MedWire News: Obese women are no more likely to have unintended pregnancies than their normal-weight peers, results from the 2002 National Survey of Family Growth show.
The researchers also found no significant difference in patterns of contraceptive use or perceived fertility between obese women and those of normal weight.
"As the obesity epidemic continues to spread in our country it is important to know how body mass index (BMI) affects the risk of unintended pregnancy as well as contraceptive use and perceived infertility," note Bliss Kaneshiro (University of Hawaii, Honolulu, USA) and colleagues.
The researchers compared unintended pregnancy rates among 3,600 women of normal weight (<25 m/kg2), 1,643 who were overweight (25-30 m/kg2), and 1,447 who were obese (>30 m/kg2).
They found that compared with normal-weight women, those who were overweight or obese had similar rates of unintended pregnancies over the past 5 years, at odds ratios of 0.95 and 0.87, respectively.
Overall, 14.2 percent of women reported a history of unintended pregnancy and women with normal BMI had the highest percentage, at 14.6 percent, compared with 13.4 percent for obese women and 14.0 percent for overweight women.
Kaneshiro and team say that prospective clinical trials specifically addressing which contraceptive methods most effectively prevent unintended pregnancy in heavier women-something their study did not investigate-are still needed.