Abstract Study question How accurate, credible, reliable and readable is online information obtained from social media content in relation to the diagnosis and management of fertility problems? Summary answer Information available on social media regarding infertility often uses language that is inappropriate for a lay audience and lacks sufficient accuracy, credibility and reliability. What is known already Social media has become a popular source of information for people seeking guidance, advice and educational resources related to their own fertility journey. Social media can provide free and easily accessible information and can act as a space for community support to share real-world experiences. Many of the platforms delivering this information have not been verified and there is a growing concern regarding the accuracy of the content on these posts. A variation in expertise among content creators and the rapid spread of anecdotal experiences may contribute to the unreliability of information. Study design, size, duration Using real-time analytics software, the #infertility was tracked prospectively during National Infertility Awareness Week, an annual campaign organised by the National Infertility Association (USA) to raise awareness around infertility, on Twitter and Instagram platforms. During this one-week period, a total of 28,612 posts containing the #infertility was posted on Twitter and Instagram. Posts containing non-English language, commercial advertising and content related solely to the lived experience of infertility, for example, a patient’s blog, were excluded. Participants/materials, setting, methods Once screening was completed, 673 posts (310 on Twitter and 363 on Instagram) were identified as containing information pertaining to the diagnosis and management of fertility problems. Two independent researchers screened the included posts. Posts were evaluated using validated instruments across four domains, including assessments of 1) credibility (White Paper instrument) 2) quality (adapted DISCERN instrument) 3) accuracy (assessed by prioritized criteria developed in consultation with healthcare professionals and researchers) and 4) Readability (Flesch-Kincaid instrument). Main results and the role of chance A total of 28,612 posts, with a reach of 285,826,087 people were identified. Once screening had been completed, there were 310 posts on Twitter containing information pertaining to infertility, with 20,136 engagements and an overall reach of 75,184,476. For Instagram, 363 posts were identified as containing information pertaining to infertility, with 46,443 engagements. The most discussed topics included: 1) lifestyle interventions including nutrition and supplements, 2) polycystic ovarian syndrome, 3) endometriosis and 4) infertility in relation to COVID and the COVID vaccination programme. Only 87 Twitter posts (28%) had clear demonstration of credibility and of those posts the information contained within them was accurate 92% of the time. Of the remaining 72% of Twitter posts, no clear credentials were displayed, and the accuracy of those posts dropped to 34%. 139 Twitter posts (45%) appeared to have an undeclared Trial registration number Not applicable