Intrapartum Ultrasound for Assessment of Fetal Progression

Official title

Intrapartum Ultrasound for Assessment of Fetal Progression: a Multicentre Randomized Within-Subject Trial Evaluating Variation in AoP and HPD According to Maternal Position and Pelvic Mobility (MaPP Study)

Overview

The use of ultrasound has been suggested to support the management of labour. According to several studies, ultrasound examination is more accurate and reproducible than clinical examination in diagnosing fetal head position, fetal station, and the prediction of labour arrest. Furthermore, there is growing evidence that ultrasound in labour may predict the outcome of instrumental vaginal delivery: a support to assess when an operative delivery is necessary. Ultrasound in labour can be performed using a transabdominal approach, mainly to determine head and spine position, or a transperineal approach, to assess head station and the situation at low stations. Several sonographic parameters have been proposed to evaluate the head station. Furthermore, all ultrasound parameters studied so far, have always been measured with the woman in a supine position. While the biomechanics of childbirth with its mechanisms (known as nutation, counter-nutation of the pelvis, and the coccyx retropulsion) together with maternal movement, promote fetal rotation and the adaptation of its diameters with those of the maternal pelvis, allowing to gain more room for the fetal descent. Moreover, in most of the studies on intrapartum ultrasound, the mobility of the pelvis has not been mentioned. The contracted pelvis is the absence of mobility that leads to fetal-pelvic disproportion, arrest of labour, and operative delivery. Maternal pelvis biomechanics studies by high technological techniques have shown that maternal shifting positions during pregnancy and childbirth can create more room in the pelvis for safe delivery. The external and internal pelvic diameters are closely related. For this reason, the evaluation of the mobility of the pelvis appears to be a necessary element to understand the ability of that pelvis to widen its diameters for fetal descent. The aim of the study is to measure the variation of AoP, HPD in the supine position and in kneeling-squat position in the same woman and the cut-offs of the new ultrasound parameters and predictive capacity for vaginal birth.

Interventions

• Other Transperineal imaging
  To measure the difference between ultrasound parameters based on maternal position: to measure the variation of Angle of progression (AoP), ), HPD(head perineum distance) expressed in millimeters, in the supine position and kneeling squat position in the same woman during the expulsion phase, in the resting step and during the push.

Primary outcome measures

• Ultrasound AoP EP [Time frame: Beginning of the expulsive phase (active second stage): with complete dilation and the perception of an urge to push.]
• Ultrasound AoP RS [Time frame: During the resting step]
• Ultrasound AoP P [Time frame: During the push]
• Ultrasound HPD EP [Time frame: Beginning of the expulsive phase (active second stage): with complete dilation and the perception of an urge to push.]
• Ultrasound HPD RS [Time frame: During the resting step]
• Ultrasound HPD P [Time frame: During the push]

Secondary outcome measures (9)

• mode of delivery [Time frame: during delivery]
• duration of labour stages [Time frame: during labour stages]
• Midwifery interventions during labour [Time frame: during labour (hours)]
• Variation in the anteroposterior diameter of the levator hiatus [Time frame: during labour (hours)]
• reasons for possible caesarean section [Time frame: immediately after caesarean section]
• Apgar Index at 1 min after delivery [Time frame: One minute after delivery]
• Apgar Index 5 minutes after delivery [Time frame: Five minutes after delivery]
• pH [Time frame: Within 1 hour after delivery]
• BE [Time frame: Within 1 hour after delivery]

Eligibility criteria

Inclusion criteria

• pregnant women with singleton pregnancies
• at term gestation (37 weeks)
• fetus in cephalic presentation
• absence of factors hindering vaginal delivery

Exclusion criteria

• complicated pregnancies
• vaginal birth after Cesarean
• twin pregnancies
• early pregnancy
• women condition that exclude vaginal birth

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Screening

Study locations

Italy · 3 centers

• Azienda Ospedaliero Universitaria Sant'Orsola Malpighi — Bologna
• Azienda Ospedale Università Padova — Padova
• Ospedale Cristo Re — Roma

Identifiers

NCT: NCT05718180 · MaPP

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗