RESUMO
The aim of the present study was to investigate the relationship between lactate level in vaginal fluid and the latent phase of labour in pregnancies complicated by preterm premature rupture of membranes (PPROM). Seventy pregnant women with PPROM during 28-34 weeks' gestation were selected for this prospective observational study. All subjects underwent a pelvic examination involving the insertion of a vaginal speculum, and lactate levels were measured in vaginal fluid samples. The relationship between the lactate levels in the vaginal fluid and the latent phase of the labour was analysed using a logistic regression test. Of the patients, 48 (68.6%) had a latent period of 48 h or less, and 22 patients (31.4%) had a latent period longer than 48 h. The median lactate level was 3.81 mmol/L in patients with a latent period ≤ 48 h, and 3.36 mmol/L in patients with a latent period > 48 h. The lactate level in vaginal fluid was not found to be distinctive in the differentiation of patients according to the duration of the latent phase (receiver operating characteristic or ROC: 0.509; 95% confidence interval or CI: 0.361-0.657; p = 0.904). There was no significant correlation between the lactate level in the vaginal fluid and the transition from the latent phase to the active phase of labour in pregnancies complicated by PPROM.