A 20-year-old pregnant woman is seen for an initial pregnancy evaluation. Screening labs showed a reactive treponemal enzyme immunoassay (EIA) test and a reactive rapid plasma reagin (RPR) with a titer of 1:16. She has no syphilis-related clinical manifestations. She is diagnosed with latent syphilis of unknown duration and scheduled to receive 3 doses of 2.4 million units of benzathine penicillin G, with each dose given 1 week apart. She received her first dose in the clinic and her second dose exactly 1 week later. For her third dose, however, she did not return on the scheduled date. Following outreach efforts, she was contacted and returned to the clinic 11 days after the second dose had been administered.