Intrapartum Ultrasonography in Labour Arrest
Condition: Ultrasonography; Pelvic Floor; Delivery Complication; Maternal-Fetal Relations
Study type: Observational [Patient Registry]

Summary: 
      Determination of fetal head position during labour is highly subjective and depends on
      clinician's experience in vaginal digital examination. Monitoring the progress of labour with
      intrapartum ultrasound (IU) exhibits higher accuracy rates. However, the dynamic process of
      labour needs very frequent sonographic examination and that may decrease the feasibility.
      Consultation to IU at certain time points can positively limit the need for ultrasound,
      increase the effectiveness of IU and allow for safer labour in consistency with traditional
      labour management. This study aims to investigate the use of IU in cases with suspected and
      diagnosed labour arrest in both the first and second stage of labour.
    

Detailed description: 
      Low-risk pregnant women with singleton, vertex fetus who are at their 36th gestational weeks
      and above with suspected first and second stages of labour arrest will be enrolled in this
      study. Intrapartum ultrasound with transperineal and transabdominal approach will be
      performed at two specific time points; 1) Suspicion of labour arrest, 2) Diagnosis of labour
      arrest. The fetal head position, station, direction, progression and the structure of pubic
      arch will be evaluated with IU.

      All ultrasound examinations will be monitored and recorded to the memory storage of
      ultrasound device. Recorded ultrasound examinations will be reviewed and measurements will be
      performed at the end of the study period by two experienced clinicians who are not involved
      in the examinations. These two blinded clinicians are not aware of labor outcomes, delivery
      types, maternal and neonatal outcomes.

      General terms are defined according to the NICE guidelines. Those are; the first stage of
      labour is established when there are regular painful contractions and there is progressive
      cervical dilatation from 4 cm. If delay in the established first stage is suspected, all
      aspects of progress in labour are assessed when diagnosing delay, including; cervical
      dilatation of less than 2 cm in 4 hours for first labours, cervical dilatation of less than 2
      cm in 4 hours, or a slowing in the progress of labour for second or subsequent labours,
      descent, and rotation of the baby's head, changes in the strength, duration and frequency of
      uterine contractions. Amniotomy is offered to a woman with suspected delay in the established
      first stage of labour and women are advised to have a vaginal examination 2 hours later, and
      diagnose delay if progress is less than 1 cm. If oxytocin is used due to insufficient uterine
      contractions delay is diagnosed as progress is less than 2 cm within 4 hours. With regard to
      the second stage of labour, for a nulliparous woman; birth would be expected to take place
      within 3 hours of the start of the active second stage in most women. The delay is diagnosed
      in the active second stage when it has lasted 2 hours and suspected delay if progress (in
      terms of rotation and/or descent of the presenting part) is inadequate after 1 hour of the
      active second stage. For a multiparous woman: birth would be expected to take place within 2
      hours of the start of the active second stage in most women. The delay in the active second
      stage is diagnosed when it has lasted 1 hour for multiparous women and suspected delay if
      progress (in terms of rotation and/or descent of the presenting part) is inadequate after 30
      minutes of the active second stage.

      The International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) practical
      guidelines on intrapartum ultrasound recommend the evaluation of head position and descent
      during the active phase of labour when labor progress is slow and when operative delivery is
      considered. The use of IU is not meant to change the classic algorithm of labour monitoring
      but to provide objective and reliable evaluations of the traditional parameters of crucial
      importance when prolonged or arrested labour is suspected.

      The aim of this study is to evaluate the use of IU in prolonged labour with optimizing the
      timing of IU.
    

Intervention name(s): Intrapartum ultrasound
Intervention type(s): Diagnostic Test
Intervention description(s): Intrapartum ultrasound will be performed by suprapubic and transperineal approach for 30 seconds.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Pregnant women whose active labour progress is prolonged
      
Keywords: intrapartum ultrasound; labour arrest; fetal head position