I found this photo on The Margaret Sanger Papers Project. One post notes that Sanger founded America’s first legal birth control clinic on Jan. 2, 1923. By the 1930s, the Birth Control Clinical Research Bureau (BCCRB) served 10K+ patients per year, and “trained thousands of doctors and nurses.”
In the undated photo above, a nurse teaches other women…I assume birth control and/or family planning. I can’t say definitely if they were doctors, nurses or patients, but I’m confident they received the most accurate information of the day.