Background
Tubo-ovarian abscess (TOA) carries long-term sequale in women of reproductive age. Consensus of the optimal treatment of tubo-ovarian abscess remains lacking. The aims of this study are to identify risk factors predicting the need for early drainage and compare clinical outcomes of current management practices of TOA.

Methods
From 2015 to 2019, a retrospective cohort study of 92 women admitted to a tertiary centre for gynaecological surgery was performed. Patients with diagnosed TOA were classified into two groups: treatment with antibiotics only, and those receiving additional drainage. Primary outcomes included length of hospital stay (LoS), length of antibiotic treatment (LoA) and need for re-intervention.

Results
In this study, 52 women (56.5%) were successfully treated with first line intravenous antibiotics; 40 (43.5%) received surgical drainage. Significant predictors for successful medical treatment only include age < 35 (OR: 0.89, 95% CI: 0.82-0.97) and abscess size < 6cm (OR: 0.17, 95% CI: 0.04-0.64), using multivariate analysis. Pyrexia ≥ 38°C predicted a need for drainage (OR: 3.82, 95% CI: 1.01-8.12). Patients who received additional drainage had significantly longer LoA, LoS and higher rates of re-intervention. Within this group, drainage within 72 hours of admission resulted in a trend towards shorter LoA and LoS than drainage after 72 hours, albeit not statistically significant.

Conclusions
Parameters include age > 35 years, pyrexia ≥ 38°C and a TOA size > 6cm may independently predict the need for drainage of TOA. Early identification of these patients is imperative for timely surgical intervention to avoid prolonged hospitalisation, antibiotic usage, and patient morbidity. More work is required to identify whether early drainage may reduce length of hospital stay and antibiotic treatment, including identifying certain patient groups who most likely to benefit from outpatient antibiotic intravenous therapy.