2.3 Interventions
Researchers applied a checklist to confirm eligibility criteria. If the parturient were eligible, she received information about the study and was invited to participate voluntarily. A Free and Informed Consent Form was requested according to the 466/12 Resolution of the National Health Council.
This research was approved by the Research Ethics Committee of the Federal University of Pernambuco under the registration numbers 2.885.560 and CAEE: 81405717.7.0000.5208 and is also registered in the Brazilian Clinical Trials Registry (ReBEC) under the identifier RBR-556d22. The description of this article followed the international standards recommended by the CONSORT Statement: Updated Guidelines for Reporting Parallel Group Randomised Trials [13].
The study sample for the primary outcome (episiotomy) was calculated considering the results of a meta-analysis [2] that obtained a RR of 0,51 and a control group incidence of 71% through the Open-epiversion 3.0 software, considering alpha and beta errors of 0,05 and 0,20, respectively. A 20% loss to follow-up was anticipated. 95% confidence level and 80% power were considered. Therefore, 62 pregnant women were necessary, 31 in the intervention group and 31 in the control group.
Randomization was carried out by placing each patient’s name in opaque envelopes that corresponded to either the intervention or the control group and were prepared by an independent researcher not directly involved in the study. The parturients were followed in three moments: right after randomization, one hour and 24 hours after delivery.
In this initial follow-up performed during prepartum and in the delivery room the duration of the second stage of labor and the maternal pushings were measured. Then, the following data were collected: personal and socioeconomic (age, marital status, schooling, family income, and occupation), clinical and obstetric data (weight, height, Body Mass Index – BMI, Systolic Blood Pressure and Diastolic Blood Pressure), postpartum hemorrhage, perineal laceration, episiotomy, gestational age, parity, route of delivery, instrumental delivery, pain, anxiety, maternal fatigue, and satisfaction. Finally, the following neonatal data were collected in the obstetric center or at the joint accommodation: newborn admission to intensive care, hypoxic-ischemic encephalopathy, 5-minute Apgar, and neonatal resuscitation.
After the diagnosis by the hospital team about the complete deletion of the cervix (10 centimeters) and effacement, the volunteer in the intervention group received guidance about the breathing pattern associated with expulsive efforts, based on the spontaneous pushing physiology: pursed lips breathing associated with open glottis in tidal volume, controlled by the woman, along with abdominal muscle efforts and perineal relaxation. The team also used communication strategies providing positive feedback and information about labor evolution and the possible sensations (Figure 1).
The control group followed the usual routine of the service team, with the use of directed pushing, regardless of maternal desire, initiated right after uterine contraction, by guiding the woman to perform a deep inspiration, initiating the effort with closed glottis for 10 seconds or more. The entire pushing protocols are described in Figure 1.