†These authors contributed equally.
Academic Editor: Andrea Tinelli
Background: Even though endometriosis is an important risk factor for pelvic inflammatory disease (PID), it is still not clear whether endometriosis influences PID after ultrasound-guided transvaginal oocyte retrieval (TVOR). Therefore, this work was designed to explore whether endometriosis will influence PID after TVOR and study the influencing factors of receiving drainage treatment to improve the outcomes of patients with PID. Methods: A retrospective study was conducted between 2004 and 2017. Data were collected from Women’s Hospital, Zhejiang University School of Medicine, China. This study included 66 patients with acute PID symptoms after TVOR with or without endometriosis. The independent factors predicting drainage treatment were determined using univariate and multivariate logistic regression analyses, and their optimal cut-off points were ascertained using a receiver operating characteristic curve. Results: Among 66 cases, there were 53 women without endometriosis and 13 women with stage III or IV endometriosis. The significantly higher maximum body temperature (p = 0.047), longer days of fever (p = 0.043) and duration of intravenous (IV) antibiotic use (p = 0.001), and more receiving drainage treatment (p = 0.002) were found in the patients with endometriosis. In vitro fertilization (IVF) cycles (odds ratio [OR] = 6.055, 95% confidence interval [CI] = 1.360–26.961, p = 0.018), puncture cyst during TVOR (OR = 60.167, 95% CI = 2.477–1461.619, p = 0.012), and pre-treatment C-reactive protein (CRP; OR = 1.022, 95% CI = 1.003–1.041, p = 0.022) were significant independent risk factors for drainage treatment. The optimal cut-off for IVF cycles and pre-treatment CRP for patients receiving drainage treatment were 2 and 40.3 mg/L, respectively. Conclusions: Patients with endometriosis had more severe PID outcomes after TVOR, requiring more attention during treatment. Early drainage treatment is recommended for patients with pre-treatment CRP levels higher than 40.3 mg/L, puncture cyst during TVOR, and those receiving more than 2 IVF cycles.