BACKGROUND: COVID-19 stay-at-home orders and research restrictions halted recruitment and follow-up of clinical research patients. Although clinical research has resumed, it is an open question whether research participation has returned to levels similar to those before COVID-19. METHODS: We used data from the TECH-PN (NCT No. NCT03828994) study, a single-center randomized controlled trial enrolling 13- to 25-year-olds with mild-moderate pelvic inflammatory disease (PID) receiving ambulatory care. We examined enrollment patterns before COVID-19 and during/after COVID-19 among those assessed for eligibility by estimating the average rate of recruitment visits for each period. We focused on this monthly rate by pandemic status, the length of stay (LOS) by pandemic status, as well as the relationship between the LOS and patient demographics. Descriptive analyses were conducted, including Student t test to compare rates between time periods and a χ2 test to compare the proportion refusing enrollment. RESULTS: The monthly enrollment rate during/after the pandemic was significantly lower than before COVID-19 (4.8 per month compared with 7.4 per month, P < 0.001). However, eligible participants' age, race, and insurance type were similar before and during/after the pandemic. Among eligible patients, LOS for receiving PID care was slightly increased, from a median of 5.4 to 6.4 hours ( P = 0.650), and the rate of refusal to participate among those eligible was similar (23% vs. 27%, P = 0.362). There were a similar number of ineligible patients because of inpatient admissions during both periods. CONCLUSION: COVID-19 pandemic restrictions negatively impacted recruitment into this randomized controlled trial. Enrollment differences may reflect ongoing perceptions of restrictions in care access or a hesitancy to use health services. More research is needed to stabilize access to ambulatory sexually transmitted infection/PID care and access to clinical trials.