As the partisan attack on Planned Parenthood heats up on Capitol Hill this week, a new study published Tuesday found that the women’s healthcare provider is in many cases the only source of contraceptive care for minority and low-income women across the country.

The analysis (pdf) was conducted by the Guttmacher Institute, a New York-based reproductive health research organization, in response to a Congressional Budget Office request.

After examining the most recent data available, Guttmacher found that, “unequivocally that for women in many areas of the country, losing Planned Parenthood would mean losing their chosen provider—and the only safety-net provider around.” Safety-net providers are institutions that provide care and services in low-income, medically underserved, immigrant, and communities of color.

The study, published at the Health Affairs blog, found that in one-fifth of the 491 counties in which Planned Parenthood sites are located, they are the sole safety-net family planning center. Further, in two-thirds of those counties, Planned Parenthood serves at least half of all women obtaining contraceptive care from safety-net health centers.

These findings debunk the myth, spread by conservative detractors of Planned Parenthood, that the care provided by the group could be easily supplanted by a publicly-funded safety-net centers, such as federally qualified health centers (FQHCs) or county health departments. In fact, the study found that the average Planned Parenthood health center serves “significantly more contraceptive clients each year” than FQHCs, or similar providers.