Washington ? Federal health officials took unusual steps in rejecting nonprescription sales of emergency contraception – and some documents suggest the decision was made before scientists finished reviewing the evidence, congressional investigators concluded.

An independent audit made public Monday found the Food and Drug Administration’s May 2004 rejection of the politically charged morning-after pill deviated from 10 years of agency practice in switching drugs from prescription to over-the-counter sales.

Long-suspicious members of Congress immediately declared that politics had trumped science, and urged the FDA’s boss to intervene to assure that a still pending reconsideration of the pill’s fate isn’t based on ideology.

In a statement, the FDA stood by its rejection.

A high dose of regular birth control, the morning-after pill lowers the risk of pregnancy by up to 89 percent if taken within 72 hours of unprotected sex. The sooner it’s taken, the better it works, but it can be difficult to get a prescription in time.

In December 2003, FDA’s scientific advisers overwhelmingly backed over-the-counter sales for all ages. But the following May, FDA leaders rejected that recommendation.

The maker reapplied, seeking to sell Plan B without a prescription to women 16 or older while younger teens continue to get a doctor’s note. In August, FDA’s then-commissioner postponed that decision indefinitely, saying it wasn’t clear how the FDA could enforce an age limit.