Severe complications of childbirth are common. Many factors have been studied to assess their imputability in the occurrence of perineal tears. While women subjectively have different push profiles in terms of intensity, frequency and duration of each push effort, no study has evaluated this variability in a relevant, simple and reproducible way. Through this work, it is expected to establish a qualitative evaluation of the expulsive efforts during childbirth in term nulliparous women by measuring the intra bladder pressure which testifies of the pressure exerted on the perineal tissues due to maternal pushing efforts

Scientific context:

It is clearly observed in clinical practice that there seems to be significant variability in the characteristics of the expulsive phase from one woman to another without this being clearly described to date. During the same expulsive phase, the number, intensity and duration of each push can be very different from one woman to another.

Considering that during expulsive efforts, the fetal head exerts pressure on the perineal tissues , the repetition of these compressions, moreover if they are prolonged or brought closer together could generate muscular lesions by hyper extension of the fibers, by microtrauma or by tissue hypoxia. These variations in the characteristics of expulsive efforts could thus modify the perineal risk for women.

More than the expulsive efforts evaluated by the recording of intra uterine pressures which has already been described, it is the evaluation of the mechanical stresses transmitted to the perineum secondary to the pushing efforts that we would like to record by the installation of a sensor pressure connected to the woman's bladder catheter.

Investigations During the second phase of labor, at 8 cm dilation, after information and obtaining free and informed consent, women will be included by one of the MD investigators.

3 visits are planned in the protocol: The first visit will be at childbirth Evaluation of the mechanical stresses transmitted to the perineum secondary to the pushing efforts by the installation of a sensor pressure connected to the woman's bladder catheter

Follow up A prospective study including nulliparous term pregnant women with 2 other visits planned at 3 months (12 to 16 weeks) and 6 months (26 to 30 weeks) after delivery, to assess secondary perineal complications

• Inclusion criteria :

  • Pregnant women aged of 18 years or more
  • 37 weeks or more of pregnancy
  • Without any previous delivery (vaginal or cesarean delivery)
  • With a cephalic presentation fetus
  • With epidural analgesia at 8 cm cervical dilatation (inclusion)

• - Exclusion criteria:

  • Pathological pregnancy (intrauterine growth restriction, pre-eclampsia etc.)
  • Untreated psychiatric disorders
  • Women under judicial protection
  • Women without health insurance