Evaluation of The Effectiveness of The Breathing Exercise On The Nausea, Vomiting And Quality of Life In The Early Pregnancy Period: A Single-Blind Randomized Controlled Trial

2.1. Study design, sampling and recruitment strategies This research was conducted as a randomized controlled experimental study with the pretest-posttest design. The research was carried out in the maternity polyclinic of a public hospital affiliated with the Health Directorate of Elazığ Province in eastern Turkey in June 2019 - May 2020. A total of 104 pregnant women took part in the research (52 pregnant women in the experimental group and 52 pregnant women in the control group). In the calculation of the sample size, the power analysis was utilized. Considering that the effect of the breathing exercise on nausea and vomiting and the quality of life in the early pregnancy period will increase the mean of the Nausea and Vomiting in Pregnancy Instrument scores eight points after the breathing exercise, the number of participants for each group was calculated as 52 pregnant women at α=0.05 significance level and with 80% power [1-β (power)=0.80].

In the research, the inclusion criteria were designated as follows: a) Having the ability to communicate, b) Being aged 15-49 years, c) Being in the 12th or an earlier week of pregnancy with a living fetus, d) Not having fetal congenital malformation, e) Not having systemic diseases (gastrointestinal system, audiovestibular, endocrine, infection, and psychological diseases) which are likely to lead to nausea and vomiting other than pregnancy-related nausea and vomiting, f) never using a medication against nausea and vomiting before.

Under the research, the following were identified as the exclusion criteria: a) Having a multiple pregnancy, b) Having fetal congenital malformation, c) Having systemic diseases that are likely to lead to nausea and vomiting, d) Using medication against nausea and vomiting, e) Having the risk of miscarriage, f) Having speech disorder.

2.2. Instruments In the collection of research data, the Personal Information Form, the Nausea and Vomiting in Pregnancy Instrument, and the 36-Item Short-Form Health Survey were used. The research data were gathered by the researcher using the face-to-face interview technique.

2.2.1. Personal Information Form In the Personal Information Form which was prepared by the researcher as per the literature review (Şahan, 2012; Acog Practıce Bulletın, 2018; Köken et. al., 2009; Aksu, & Şirin 2007), seven questions addressed the pregnant women's socio-demographic characteristics (age, education, employment status, income level, body mass index-BMI) and ten questions pertained to the pregnancy (the number of previous pregnancies, whether the pregnancy was unwanted or not, the number of nausea and vomiting per day, and so on.), and hence, the form contained 17 questions in total.