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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SCREENING
Masking
NONE
Enrollment
177
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.
Azienda Ospedaliero Universitaria Sant'Orsola Malpighi
Bologna, Italy
Azienda Ospedale Università Padova
Padua, Italy
Ospedale Cristo Re
Roma, Italy
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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: During the push
mode of delivery
mode of delivery
Time frame: during delivery
duration of labour stages
duration of labour stages up to 18 hours
Time frame: during labour stages
fetal weight
fetal weight
Time frame: at delivery
fetal position
fetal position
Time frame: at the beginning of delivery
reasons for possible caesarean section
reasons for possible caesarean section
Time frame: immediately after caesarean section
Apgar Index at 1 min after delivery
Apgar Index
Time frame: One minute after delivery
Apgar Index 5 minutes after delivery
Apgar Index
Time frame: Five minutes after delivery
pH
pH
Time frame: Within 1 hour after delivery
BE
Bases excess
Time frame: Within 1 hour after delivery
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