Bloomingdale's yesterday agreed to pay $50,000 in civil penalties to settle a Federal Trade Commission complaint charging that it has discriminated against women in violation of the Equal Credit Opportunity Act.

The complaint was the first civil penalty action brought by the FTC under the statute.

The commission alleged that Bloomingdale's had failed to consider alimony, child support and separate maintenance payments, as well as money earned from part-time employment, as income in evaluating credit applications. Failure to do so violates the regulations implementing the ECOA, the FTC charged.

The credit law, which became effective in 1975 and was amended two years later, prohibits discrimination on the basis of sex, marital status, race, religion, national origin and age in any aspect of a credit transaction.

The agency also alleged that Bloomingdale's failed to consider pensions, annuities or other retirement benefits, and public assistance payments in evaluating credit applications.

In a settlement agreement filed yesterday in U.S. District Court in Cincinnati, and accepted by U.S. District Judge Timothy S. Hogan, Bloomingdale's agreed to revise its method of evaluating credit-worthiness to comply with the law. It also agreed to contact all applicants rejected during 1976 and 1977 whose rights may have been violated and to invite them to reapply for a charge account.

Besides agreeing to pay the $50,000 in civil penalties, the consent settlement also requires the store to make sure it tells rejected credit applicants the specific reasons for their denial, as required by the law. The FTC alleged that the store gave vague rather than specific reasons for rejecting credit applications.

In agreeing to the consent agreement, neither Bloomingdale's nor its parent company, Federated Department Stores, Inc., admits a violation of the law; suchagreements are for settlement purposes only.