Study design: Study with historical control, the research was approved by the research and ethics committee in health research of HGZ 4.
Study population: Women in spontaneous labor with the following characteristics: nulliparous, term, singleton, vertex presentation, under 40 years and in active phase, without any comorbidity, who wanted to participate and were treated in the labor and delivery unit, from Monday to Sunday, during the three shifts in HGZ No.4 of the IMSS, patients with maternal and / or fetal indications of cesarean delivery were excluded.
Sample: The sample size was calculated with the G-Power 188.8.131.52 program, for difference of proportions in two independent proportions (z test), with two tails, assuming, according to local statistical data, that the outcome of Cesarean deliveries in nulliparous with usual obstetric care was 45% and in nulliparous with emotional support it was 20%, with 95% confidence and 80% of power, the sample size was 54 patients per group, the control group was worked in the July-September 2018 period and the study group in the October-December 2018 period.
Procedure: The control group received the usual obstetric care, without continuous intrapartum support. The study group received the usual obstetric care plus continuous intrapartum support that was provided by a Bachelor of Nursing and Obstetrics.
A professional doula provided training to the Bachelor of Nursing and Obstetrics so that they could provide the support effectively, this training covered three fundamental aspects: 1) emotional support, 2) physical support and comfort measures and 3) information and advice. The emotional support consisted in establishing an effective communication between the patient and the nurse in order to dispel fears and doubts and instill security in an environment of understanding, availability, respect and intimacy.
The physical support and comfort measures were provided through massage, tactile contact, assistance to adopt different positions for pain relief.
The information and advice was characterized by providing the patient with information about the development of labor and the medical procedures used, as well as guiding the woman in breathing and relaxation techniques.
Measurement of variables: The primary outcome was the cesarean delivery rate, the characteristics of interest for the initial homogeneity of the control group and the study group were maternal age, dilation at the time of admission, Body Mass Index (BMI) before and during delivery, years of education, as secondary outcomes in labor and delivery, labor time was measured, oxytocin application, obstetric analgesia and Apgar score in the first and fifth minute and indication for cesarean.
Statistical analysis. In the verification of the initial characteristics between the control group and the study group, and of the secondary outcomes, the statistical tests used depended on the scale of measurement of the variables and the statistical assumptions of each test (Student's t test or Mann-Whitney U test, Chi-square test or Fisher's exact test), in the numerical data to check the assumption of normality the Shapiro-Wilk test was used, the Mann-Whitney U test was used only when the assumption of normality was clearly violated, otherwise the student's t test was used, since it is a robust test for the assumption of normality, to evaluate the primary outcome, the clinical usefulness of the intrapartum continuous support the rate (%) of cesarean deliveries was used, estimating the risk ratio, the absolute risk reduction and odds ratio, all the statistical tests were contrasted with a significance of p <0.05 for two tails with 95% confidence intervals, In addition, a binomial logistic regression model was carried out taking as dependent variable the result of labor (vaginal or cesarean) and as independent variable the group (control or study), the model was adjusted with possible covariates, the statistical analysis was performed in the Statistical Package for Social Sciences IBM SPSS version 24.