BackgroundThe MsFLASH (Menopause Strategies: Finding Lasting Answers for Symptoms and Health) Network recruited into five randomized clinical trials (n = 100–350) through mass mailings. The fifth trial tested two interventions for postmenopausal vulvovaginal symptoms (itching, pain, irritation, dryness, or pain with sex) and thus required a high level of sensitivity to privacy concerns. For this trial, in addition to mass mailings we pilot tested a social media recruitment approach. We aimed to evaluate the feasibility of recruiting healthy midlife women with bothersome vulvovaginal symptoms to participate in the Vaginal Health Trial through Facebook advertising.MethodsAs part of a larger advertising campaign that enrolled 302 postmenopausal women for the 12-week randomized, double-blind, placebo-controlled Vaginal Health Trial from April 2016 to February 2017, Facebook advertising was used to recruit 25 participants. The target population for recruitment by mailings and by Facebook ads included women aged 50–70 years and living within 20 miles of study sites in Minneapolis, MN and Seattle, WA. Design of recruitment letters and Facebook advertisements was informed by focus group feedback. Facebook ads were displayed in the “newsfeed” of targeted users and included a link to the study website. Response rates and costs are described for both online ads and mailing.ResultsFacebook ads ran in Minneapolis for 28 days and in Seattle for 15 days, with ads posted and removed from the site as needed based on clinic flow and a set budget limit. Our estimated Facebook advertising reach was over 200,000 women; 461 women responded and 25 were enrolled at a cost of US$14,813. The response rate per estimated reach was 0.22%; costs were US$32 per response and US$593 per randomized participant. The social media recruitment results varied by site, showing greater effectiveness in Seattle than in Minneapolis. We mailed 277,000 recruitment letters; 2166 women responded and 277 were randomized at a cost of US$98,682. The response rate per letter sent was 0.78%; costs were US$46 per response and US$356 per randomized participant. Results varied little across sites.ConclusionRecruitment to a clinical trial testing interventions for postmenopausal vaginal symptoms is feasible through social media advertising. Variability in observed effectiveness and costs may reflect the small sample sizes and limited budget of the pilot recruitment study.