Fewer women aged 20-44 years are using sterilization as their primary method of contraception, despite no-cost coverage of the procedure under the Affordable Care Act.

Sterilization rates in 2011-2013 for women in this age group was 25%, down from 27% in 2002, according to a new report from the Kaiser Family Foundation. Rates declined across income groups, dropping from 41% in 2002 to 37% in 2011-2013 for women whose incomes were up to 149% of the federal poverty level (FPL). For women with incomes within 150%-299% of the FPL, the rate declined from 33% to 28%, and for those at 300% or more of the FPL, the rate declined from 20% to 18%, according to the report .

While expanded coverage under the ACA may, in the long run, lead to greater use of sterilization by women, “it remains to be seen whether the growing availability of [long-acting reversible contraception] will offset this as IUDs and implants serve as semi-permanent substitutes for sterilization,” the Kaiser researchers wrote.

From 2011 to 2013, about 5% of men aged 15-44 years reported undergoing a vasectomy, according to Kaiser. The ACA does not require health plans to cover sterilization for men, but two states – Vermont and Maryland – have passed laws requiring coverage within their borders in the future.

Male sterilization rates increased with age (1% of those aged 15-34 years, compared with 13% of those aged 35-44 years), income (3% for those below 200% of the FPL, 5% for those 200%-399%, and 10% for those above 400%), and education (3% of those with up to a high school diploma/GED, 5% of those with some college, and 13% of those with at least a 4-year college degree). Comparative changes in male sterilization rates were not provided.