Intrapartum Ultrasound for Assessment of Fetal Progression (MaPP)

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)

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Labor, Obstetric
• Intervention / Treatment: Other: Transperineal imaging

• Study Type: Interventional
• Enrollment (Estimated): 105
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Alessia Selmin; Phone Number: +390498214434; Email: alessia.selmin@unipd.it
• Study Contact Backup: Name: Honoria Ocagli, PhD; Email: honoria.ocagli@ubep.unipd.it

Study Locations

• Italy
  • Bologna, Italy
    • Azienda Ospedaliero Universitaria Sant'Orsola Malpighi
    • Contact: Aly Youssef; Email: aly.youssef78@gmail.com
    • Principal Investigator: Aly Youssef, MD
  • Padova, Italy
    • Azienda Ospedale Universita Padova
    • Contact: Alessia Selmin; Email: alessia.selmin@unipd.it
    • Principal Investigator: Silvia Visentin, MD
  • Roma, Italy
    • Ospedale Cristo Re
    • Contact: Ilenia Mappa, MD; Email: mappa.ile@gmail.com
    • Contact: Giuseppe Rizzo, MD; Email: giuseppe.rizzo@uniroma2.it
    • Principal Investigator: Giuseppe Rizzo, MD
    • Sub-Investigator: Ilenia Mappa, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Pregnant women undergoing positional ultrasound assessment; Before the onset of labour, the woman will be randomized to the order of the position during the intrapartum transperineal ultrasound (firstly supine position and secondly kneeling-squat, or vice-versa).	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.

What is the study measuring?

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 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
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
duration of labour stages	duration of labour stages up to 18 hours	during labour stages
Midwifery interventions during labour	Midwifery interventions during labour	during labour (hours)
Variation in the anteroposterior diameter of the levator hiatus	Variation in the anteroposterior diameter of the levator hiatus	during labour (hours)

Collaborators and Investigators

• Sponsor: University of Padova
• Collaborators: Azienda Ospedaliera di Padova

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): July 31, 2029
• Study Completion (Estimated): July 31, 2029

Study Registration Dates

• First Submitted: May 6, 2022
• First Submitted That Met QC Criteria: January 29, 2023
• First Posted (Actual): February 8, 2023

Study Record Updates

• Last Update Posted (Actual): June 18, 2026
• Last Update Submitted That Met QC Criteria: June 16, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: MaPP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No