Equipment and personnel discontinuity

Objectives:

• Evaluation of the correlation between the sonographic parameter and clinical findings (e.g. digital examination) in any cephalic (not only occipital anterior) position
• Examination of the relationship between various sonographic parameters
• Determination of intraobserver and interobserver variation in obtaining the sonographic measurements
• Analysis of the temporal variation of the different sonographic measurements in normal spontaneous vaginal delivery versus obstructed labor in fetuses with occiput anterior versus those with persistent occiput posterior
• Establishment of a sonopartogram that should replace in an objective way Friedmann
• Establishment of cut-off values that may help clinicians to choose between vaginal operative delivery or caesarean section
• Another interesting aspect of intrapartum transperineal ultrasound imaging is whether there is a psychological benefit to the patient in being able to follow on the ultrasound screen how fetal head descent and position are being assessed objectively.

Objectives:

• Evaluation of the correlation between the sonographic parameter and clinical findings (e.g. digital examination) in any cephalic (not only occipital anterior)
• Examination of the relationship between various sonographic parameters
• Determination of intraobserver and interobserver variation in obtaining the sonographic measurements
• Analysis of the temporal variation of the different sonographic measurements in normal spontaneous vaginal delivery versus obstructed labor in fetuses with occiput anterior versus those with persistent occiput posterior
• Establishment of a sonopartogram that should replace in an objective way Friedmann
• Determination of cut-off values that may help clinicians to choose between vaginal operative delivery or caesarean section
• Investigation whether there is a psychological benefit to the patient in being able to follow on the ultrasound screen how fetal head descent and position are being assessed objectively.

Methods:

Unselected population Personal characteristics: GA, BMI, age, gesta, para Gestational age of more than 37 completed weeks dated by first- and/or mid-trimester scan.

Each patient provide informed consent before the ultrasound measurements. Transperineal ultrasound imaging and digital examinations in laboring patients with a singleton fetus in cephalic/pelvic presentation. Patients examined in their labor rooms.

Admission time:

• active labor demonstrated by regular uterine contractions and changes in cervical dilatation of more than 2 cm,
• subgroup: prolonged second stage of labor (full cervical dilatation for >3 h if regional anesthesia was administered or 2 h in the absence of regional anesthesia in nulliparous women, or for >2 h with regional anesthesia or 1 h without anesthesia in parous women).

Empty bladder. Ultrasound machine with a 3.5-5MHz transducer used for the TA and TPU measurements. The probe enclosed in a latex glove covered with ultrasound gel and was then placed between the labia below the pubic symphysis/perineal.

Measured parameters:

Clinical examination (digital vaginal + Leopold) followed immediately after by the acquisition of the sonographic planes necessary to evaluate:occiput position, the long axis of the pubic symphysis, the infrapubic line, the progression angle, the distance of progession, the direction of progression, the midline angle, the head to perineum distance.

Identification and measurement of caput succedaneum (vertical+orizontal) and molding (vertical) when present.

All parameters recorded electronically for later analysis + volumes, when possible.

TPU scans performed at different times during labor,

• Hourly until complete dilation (1st phase)
• At 10 minutes after complete dilation (2nd phase) (at least one contraction between the examinations).

Notation of time delivery later used to calculate the interval from scanning to delivery.

In all cases measurements are performed in concert with digital examinations (immediately after).

Intraobserver and interobserver analysis 100 women assessed by TPU examination in the study, have at least one set of two replicated scans obtained at approximately the same time. These women provide sets of scans at various times throughout labor, used to assess intraobserver variability.

In order to assess interobserver variability, a second/independent and well trained observer, blinded to the other's results,

• obtain duplicate sets of scans at distinct times of labor among randomly selected women (one woman repeated at three time points). The consecutive scans performed with no more than 3 min between the assessments of the two observers
• or measuring the parameters stored on 3D volumes by the first observer The goal is to generate paired sets of replicated images under nearly identical conditions.

The measurements from the ultrasound scanning are obtained offline, after the acquisition of the described planes, on the images stored on the US machine hard disk.

Thus, the managing obstetrician is blinded to the transperineal ultrasound findings. Head position obtained by ultrasound imaging is communicated in case of clinical misdiagnose because of ethical reasons.

The decision whether expectant management, vaginal extraction or Cesarean section is appropriate is made exclusively on the basis of clinical examination.

Demographic data are collected including length of the second stage of labor, mode of delivery, maternal and neonatal outcome.

Inclusion Criteria:

• active labor
• singleton pregnancy
• eutrophic fetus
• cephalic presentation

Exclusion Criteria:

• indication for elective caesarean section
• non-cephalic presentation
• prior caesarean delivery
• fetal hypotrophy or macrosomy
• multiple pregnancies

The pregnant women admitted in active labor at term were considered eligible for the study.

They are included in the study consecutively, depending on the availability of the US operators involved.