House Republicans have begun an investigation into Planned Parenthood’s use of federal funds, questioning whether the national network of abortion providers has proper checks in place to prevent violations of federal law.

Democrats and Planned Parenthood itself have blasted the investigation as a partisan move designed not only to score political points but also to curtail health care for women.

The investigation, announced by Rep. Cliff Stearns, chairman of the Energy and Commerce Committee’s investigation subcommittee, in a letter earlier this month to Planned Parenthood Federation of America, asks for audits and other information about PPFA’s financing.

Mr. Stearns specifically asked for information on how the organization segregates money to ensure federal funds don’t pay for abortions.

“The committee has questions about the policies in place and actions undertaken by PPFA and its affiliates relating to its use of federal funding and its compliance with federal restrictions on the funding of abortion,” Mr. Stearns, Florida Republican, wrote...