Introduction Trichomonas vaginalis (TV) is not common in the UK, with under 7,000 cases in 2015. It is associated with poor pregnancy outcomes, and consensus on treatment pathways in persistent infection is needed. We present 3 cases of TV infection in pregnancy from 2 UK centres.

Methods A retrospective review of electronic case records was performed.

Results The median age was 21 years (range 20–31), with a median presentation at 13 weeks (range 7–22). Discharge was the main presenting symptom. Initial microscopy was performed in 2/3 and was positive; culture was positive in 3/3. All patients initially received oral Metronidazole 400mg twice daily for 5–7 days. At test of cure (TOC), one patient (Pt 1) remained positive, the second (Pt 2) did not attend, and the third (Pt 3) was negative. However, Pt 2 and Pt 3 re-presented after 5 weeks and 3 months, respectively: Pt 2 reported poor adherence; Pt 3 denied poor adherence or re-infection risk. All underwent further treatment. Pt 1 required 3 treatment courses before cure was achieved, with Metronidazole 800mg tds for 1 week. Pt 2 received 4 courses of oral or IV Metronidazole; she awaits TOC. Pt 3 received 5 different antibiotic courses, then opted to deliver and wean her baby before re-engaging with care. All denied re-infection risk after the second treatment.

Discussion Factors that contribute to persistent TV infection in pregnancy include re-infection, poor adherence, resistance, poor engagement, and concerns about teratogenicity. Further research is needed to identify the optimal treatment strategy.