Intrapartum Ultrasound for Assessment of Fetal Progression

Study Overview
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Brief Summary
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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, HSD, HPD, PAA 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.

Official Title
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Intrapartum Ultrasound for Assessment of Fetal Progression: a Randomised Controlled Trial to Evaluate the Variation of AoP, HSD, HPD, MLA, PAA According to Maternal Position and Pelvis (MaPP Study)

Conditions
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Labor, Obstetric

Intervention / Treatment
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* Other: Transperineal imaging


Participation Criteria
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Eligibility Criteria
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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
Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Screening
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Supine<br>Measures are performed first in the supine position and then in a flexible sacrum position | Other: Transperineal imaging<br>* To measure the difference between ultrasound parameters based on maternal position: to measure the variation of AoP (Angle of progression), MLA (Midline Angle), PAA(pubic arch angle expressed in grades) HSD (head-symphysis distance) 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.<br>|
| Active Comparator: Flexible<br>Measures are performed first in a kneeling squat position and then in the supine position | Other: Transperineal imaging<br>* To measure the difference between ultrasound parameters based on maternal position: to measure the variation of AoP (Angle of progression), MLA (Midline Angle), PAA(pubic arch angle expressed in grades) HSD (head-symphysis distance) 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ultrasound AoP EP | To measure AoP (Angle of progression), expressed in degrees in the supine position and kneeling squat position in the same woman during the expulsion phase (EP) up to 3 hours | Beginning of the expulsive phase (active second stage): with complete dilation and the perception of an urge to push. | 
| Ultrasound AoP RS | To measure AoP (Angle of progression), expressed in degrees in the supine position and kneeling squat position in the same woman during the resting step (RS) up to 3 hours | During the resting step | 
| Ultrasound AoP P | To measure AoP (Angle of progression), expressed in degrees in the supine position and kneeling squat position in the same woman during the push (P) up to 3 hours | During the push | 
| Ultrasound MLA EP | To measure MLA (MidlineAngle) expressed in degrees in the supine position and kneeling squat position in the same woman during the expulsion up to 3 hours | Beginning of the expulsive phase (active second stage): with complete dilation and the perception of an urge to push. | 
| Ultrasound MLA RS | To measure MLA (MidlineAngle) expressed in degrees in the supine position and kneeling squat position in the same woman during the resting step up to 3 hours | During the resting step | 
| Ultrasound MLA P | To measure MLA (MidlineAngle) expressed in degrees in the supine position and kneeling squat position in the same woman during the push up to 3 hours | During the push | 
| Ultrasound PAA EP | To measure the PAA (pubic arch angle) expressed in degrees in the supine position and kneeling squat position in the same woman during the expulsion phase up to 3 hours | Beginning of the expulsive phase (active second stage): with complete dilation and the perception of an urge to push. | 
| Ultrasound PAA RS | To measure the PAA (pubic arch angle) expressed in degrees in the supine position and kneeling squat position in the same woman during the resting step up to 3 hours | During the resting step | 
| Ultrasound PAA P | To measure the PAA (pubic arch angle) expressed in degrees in the supine position and kneeling squat position in the same woman during the push up to 3 hours | During the push | 
| Ultrasound HSD EP | To measure the HSD (head-symphysis distance) expressed in millimeters, in the supine position and kneeling squat position in the same woman during the expulsion phase up to 3 hours | Beginning of the expulsive phase (active second stage): with complete dilation and the perception of an urge to push. | 
| Ultrasound HSD RS | To measure the HSD (head-symphysis distance) expressed in millimeters, in the supine position and kneeling squat position in the same woman during the resting step up to 3 hours | During the resting step | 
| Ultrasound HSD P | To measure the HSD (head-symphysis distance) expressed in millimeters, in the supine position and kneeling squat position in the same woman during the push up to 3 hours | During the push | 
| Ultrasound HPD EP | To measure the HPD (head perineum distance) expressed in millimeters, in the supine position and kneeling squat position in the same woman during the expulsion phase up to 3 hours | Beginning of the expulsive phase (active second stage): with complete dilation and the perception of an urge to push. | 
| Ultrasound HPD RS | To measure the HPD (head perineum distance) expressed in millimeters, in the supine position and kneeling squat position in the same woman during the resting step up to 3 hours | During the resting step | 
| Ultrasound HPD P | To measure the HPD (head perineum distance) expressed in millimeters, in the supine position and kneeling squat position in the same woman during the push up to 3 hours | During the push | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| mode of delivery | mode of delivery | during delivery | 
| duration of labour stages | duration of labour stages up to 18 hours | during labour stages | 
| fetal weight | fetal weight | at delivery | 
| fetal position | fetal position | at the beginning of delivery | 
| reasons for possible caesarean section | reasons for possible caesarean section | immediately after caesarean section | 
| Apgar Index at 1 min after delivery | Apgar Index | One minute after delivery | 
| Apgar Index 5 minutes after delivery | Apgar Index | Five minutes after delivery | 
| pH | pH | Within 1 hour after delivery | 
| BE | Bases excess | Within 1 hour after delivery |