WASHINGTON – In very obese women, treatment of menorrhagia with levonorgestrel intrauterine system may be slightly less effective, but the treatment’s success rate justifies its use, according to a study conducted by researchers at the University of Michigan.
In addition, levonorgestrel intrauterine system (LNG-IUS) "may be an especially important treatment choice for women at high surgical risk," the authors reported.
Although studies have shown the effectiveness of LNG-IUS in treatment of menorrhagia, most have not considered the role of body mass index (BMI), said Ms. Paige C. Fairchild, a medical student at the university who presented the study at the annual meeting of the American College of Obstetricians and Gynecologists.
The team conducted a retrospective chart review of 398 women with menorrhagia who were treated with LNG-IUS between 1999 and 2009 within the University of Michigan Health System, Ann Arbor. Nearly 50% had BMI of 30 kg/m2 or greater; 25% had BMI of 35 or greater. Treatment failure was defined as removal of LNG-IUS for continued menorrhagia, need for additional treatment, or expulsion. Continued menorrhagia was uncommon in all BMI groups, but it was most common in women with BMI greater than 34 kg/m2, compared with those in all BMI groups (6.9% vs. 3.3%).
Also, removal of LNG-IUS because of continued menorrhagia was more common among women who had BMI greater than 34, compared with those in all BMI groups (6.9% vs. 4.1%).
The odds of surgery within 2 years of LNG-IUS removal also was higher in obese patients (2.6 times), compared with other groups.
Some factors that might contribute to the reduced effectiveness of LNG-IUS in obese women are larger uterus, persistent unopposed estrogen endometrial stimulation, or poor placement/difficulty in achieving fundal placement, Dr. Vanessa Dalton of the department of obstetrics and gynecology at the university and one of the study authors said in an interview.
Despite the findings, the authors concluded that the high continuation rates of LNG-IUS and low surgery rates indicate that the treatment is still a good option for women with a high BMI.
One of the limitations of the study was that it was observational and "that cannot assess details about decision-making. It is possible that providers are more likely to recommend surgical treatment for obese women than [for] normal weight women," Dr. Dalton said.
"Additional analysis is ongoing to further characterize predictors of treatment failure," she added.
Ms. Fairchild and Dr. Dalton said that they had no relevant financial disclosures.