EP19.10: Cervical length changes prior to the onset of spontaneous labour at term: a longitudinal study

The diagnosis of labour is the greatest challenge in clinical obstetrics as it is retrospective diagnosis. Cervical sonography provides objective assessment of cervical length (effacement/shortening) for definition of effacement. The aim of this study was to determine whether changes in cervical length can be detected prior to the onset of spontaneous labour at term. A longitudinal study was conducted to serially measure cervical length at every 2-3 days intervals starting at the 37th week in 46 with uncomplicated pregnancies. Linear mixed effect modelling was used to account for dependence due to serial cervical length measurements. Difference in cervical length between parous and nulliparous was adjusted for maternal characteristics and gestational age at cervical measurement. 1) The median (range) cervical length examination was 6 times (1-12) per participant; 2) women with cervical length percentile ≤10th had delivery within 2 days; and they were 3.34 times more likely to deliver than those with percentile >10th percentile; 3) nulliparous women had longer cervical length compared to parous women in the last 3 weeks prior to spontaneous and this difference was significant even after adjusting for maternal characteristics; 4) however, nulliparous women had subsequently reduction of cervical length more rapidly than multiparous women (i.e. faster reduced 2mm per day compared to multiparous women) (see figure 1). Cervical length shortening can be detected 3 weeks prior to the onset of labour at term. Changes in cervical length differ according to parity status. Cervical length measurement might be used as an index of onset of labour at term. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.