Safe Natural Delivery by Using a New Inflatable Ergonomic Three Chambers Belt

A randomized, single blind, controlled, prospective study was performed. Subjects were nulliparous women who delivered at a community setting hospital (U.O.C. Obstetrics and Gynecology, "San Giuseppe" Hospital, Empoli, Italy) between January 24, 2011 and March 24, 2011. Vaginal deliveries were eligible. Patients were therefore divided into two groups by randomly numbered envelopes upon full dilatation of the cervix, and allocated to the following two groups:

1. The Study Group (n=40 patients) in whom the inflatable belt was applied with the correct pressures (ranging from 80 to 150 mm/Hg, see below the description of the protocol)during Labor and Delivery
2. The Control Group (n=40 women), in whom the belt was inflated with minimal pressures (from 10 to 20 mm/Hg) During Labor and Delivery To test whether differences between experimental groups are statistically significant, the sample-size should be calculated "a priori". To do this, a primary end-point has been identified: incidence of perineal-cervical lacerations. The sample-size (n > 62 subjects for two groups) will be obtained using STATA program by a two-tailed test [alpha level of 0.05 and 90% of statistical power (1-Beta)], to detect statistically significant reduction from 50% to 10% or less with respect the primary end-point. Therefore a randomized sample size of 40 pregnant women per group was chosen to allow for possible refusals or withdrawals.

Data collected from delivery records, retrospectively obtained and reviewed, will include: patient's age, race, parity, patient's body mass index (BMI, kg/m2) at the time of delivery, and body weight change during pregnancy (defined as the difference between maternal pre-pregnant body weight and body weight at delivery), as part of the ante-partum information. For the intra-partum information, gestational age at delivery, duration of second phase of labor, use of intravenous oxytocin, episiotomy, cervical laceration (as requiring surgical repair for hemostasis), severe perineal lacerations (defined as third- or fourth- laceration, while mild perineal laceration was defend as first- or second- perineal laceration), vacuum extraction, forceps delivery, use of uterine fundal pressure maneuver were abstracted. All The study Group will followed up for 15 days after delivery Fetal weight was estimated by the combination of biparietal diameter, abdominal circumference and femur length. The mean percent difference between the predicted and actual weight was 9.6% corresponding to a mean overestimation of 294 g or underestimation of 314 g. These values are consistent with most reports in the literature.

The study will be performed according to the guidelines of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH); the declaration of Helsinki regarding the Standard operating procedures for clinical investigators (GCP); the General requirements for Clinical investigation of medical devices for human subjects. Finally, the local ethical committee approved the study protocol, and all patients received detailed information about the study and the procedure, to which they gave their written consent.

The inflatable belt (Baby-guardTM ) and study protocol The Baby-guardTM (CABEL s.a.s. Costruzioni Elettroniche, Pistoia, Italy) consists of a disposable, ergonomic, three chambers, inflatable belt, and a detector of electro-physiological signals from maternal abdomen (i.e. fetal heart and maternal heart signals - Figure 1). myographic uterine activity). Three chambers that can be separately swollen one from the other in order to repositioning fetal body compose the inflatable belt. The three belt chambers are filled according to the pressures set by the operator (midwife/MD) and allow to gently positioning of the fetus in the wright position towards the pelvis. Once the correct fetal position has been obtained, all three chambers are inflated in synchronously with uterine contraction. The maternal and fetal monitoring unit is composed by a touch-screen computer, that records electro-physiological signals collected by a signal amplifier deriving from the mother (uterine contractions and the maternal heart rate) and the fetus (fetal heart rate and the possibility of Doppler parameters of fetal heart). All parameters and signals detected by the Baby-guardTM system are storable on the touch-screen computer hard disk, as per request of the European Community rules on safety (UNI EN60601)].