Federal Trade Commissioner Patricia P. Bailey is a Republican and she is married to Douglas Bailey of the prominent Republican consulting firm Bailey and Deardourff. The night before she went to San Antonio to speak at the National Women's Political Caucus convention, she told her husband she was going to speak out about the frustrations of moderate Republican women with the Reagan administration. She knew he could end up paying the price. "In fairness," she said yesterday, "I had to tell him."

Bailey's speech became front page news in last Sunday's papers. In it she thanked President Reagan for producing the gender gap and for proving that women are a "political force to be reckoned with." She talked about the atmospheric changes the Reagan administration had brought about and thanked the president for "creating a climate that has exposed for us the shallowness of our society's commitment to our equality." She accused President Reagan of "benign bewilderment in response to the women's revolution which gives license to bigotry at all levels and in every quarter of the land. That is the lesson of the last three years."

Bailey was named to the FTC by President Carter. When he was setting an example by appointing women to top jobs, Bailey said, she used to get phone calls from male corporate leaders who were also aggressively seeking ways of hiring and promoting women. "I haven't had one single call of that kind in three years," she said.

She cited a Wall Street Journal article in which executive recruiters said the movement to hire women executives has "nearly stopped." She pointed to recent newspaper stories about studies that blame working mothers for their children's inferior performance in school and for their husbands' heart-disease rates. "How long has it been since we have had to read junk like that?" she asked. And she concluded her speech with an attack on President Reagan for endorsing constitutional protection for unborn fetuses but not for living women.

Why did she do it? She said yesterday that she finally decided to speak out after talking to another woman in the party whom she greatly admires. "She said she felt the force that was impelling me to make the speech was the same one that she was feeling . . . . She said if I felt indeed the time had come to say some of these things, then it was time to say them.

"The atmosphere and the climate that has been created seem to me to be very detrimental for our progress," said Bailey, adding that she was "giving expression to what I know to be the views of a lot of people." Republican women, particularly those in the 40-to-60 age group, she said, are concerned about the gender gap and the movement of younger women to the Democratic Party. "Unless we can get hold of some of these active, interesting women in the age group below us, what is going to happen to our party?

"We know it's never going to be easy. What we would like to see is a climate and environment which fosters continuous progress, even if it's slow. We not only feel very demoralized for ourselves when that atmosphere doesn't exist, we know what it can mean for the future of the party."

Bailey's concern is backed by an ABC-Washington Post poll taken in June that shows the gender gap exists even between Republican men and Republican women. President Reagan enjoys a 62 percent rating of strong approval among Republican men, with 26 percent approving the way he is handling his job "somewhat."

Republican women, however, give him a more lukewarm endorsement: only 45 percent strongly approve of the way he is handling his job, and 36 percent approve somewhat. Republican women give him anywhere from a 7- to 10-point lower approval rating than men do on a variety of questions ranging from his handling of the economy, to world affairs, to efforts to limit nuclear weapons.

The "atmospherics" Bailey talked about in San Antonio are the kinds of intangibles that don't show up in polling questions, but they do show up at the polls. The numbers spell trouble for the Republican Party and a ticket headed by President Reagan, even among Republican women. But Bailey's speech probably tells as much about the depth of disenchantment among moderate Republican women as any numbers ever could.

Part of her family's livelihood depends on Republican candidates. She took a stand for women and for her party, knowing full well there could be a political and personal cost.