Association between lactate in vaginal fluid and time to spontaneous onset of labour from women with suspected prelabour rupture of the membranes.

摘要

Sir, We read with interest the article by Wiberg-Itzel et al. and wish to address issues with both the study design and the conclusions. The diagnosis of prelabour rupture of the membranes (PROM) is remarkably easy when, on speculum examination, a pool of liquor is seen in the posterior vaginal fornix, and fluid trickles from the cervical os when the woman coughs. The diagnosis is notoriously difficult when the history is convincing but the vagina is dry. We are astounded that in this study the authors have included women with confirmed PROM and as well as those with 'suspected' PROM, defining the latter as 'a history of limited water-like secretion from the vagina experienced by the woman, which needed speculum examination to confirm or exclude ruptured membranes'. As the objective was to assess the predictive value of lactate fol-lowing PROM, surely this study would have been infinitely more rigorous had they studied lactate in women where PROM was unequivocal. Including women with equivocal PROM raises all sorts of confounding variables which render data interpretation almost impossible.