Sample size and sampling method
critically ill
CRITICALLY ILL
The study's main objective was to compare the proportion of births that occur in health facilities; we used the estimated proportion of the outcome variable (births in health facilities) in the two groups. According to the 2019 EDHS report, 43% of births in rural areas were assisted by skilled providers. We assumed that the proposed intervention in this study would increase this proportion by 10 to 53%. We used Stata version 15 software to calculate the sample size for a two-sample proportions test. The following assumptions were made: alpha = 0.05 (significance level), Power = 0.80 (probability of detecting a difference between the groups), Intra-cluster correlation = 0.05 (a measure of how similar the observations are within clusters), p1 = 0.43 (estimated proportion of births in health facilities in the control group), p2 = 0.53 (estimated proportion of births in health facilities in the intervention group) and six pair of clusters.Based on these assumptions, the required sample size was 164 pregnant women per cluster. After considering a 10% loss to follow-up, the final calculated sample size was 1082 (541 intervention clusters and 541 control clusters).A complete census of twelve clusters was conducted to identify pregnant women who were eligible to enrol into the study. The inclusion criteria were that the pregnant woman had resided in the selected kebele cluster for at least six months, had given birth five years preceding the survey, and had a gestational age of less than 27 weeks (end of the second trimester). Pregnant women who met the inclusion criteria but were critically ill at enrolment or reluctant to participate were excluded. A buffer cluster was formed between the clusters to prevent information from being shared between the intervention and control arms. The census identified 1447 pregnant women who underwent eligibility assessments. Of these, 732 were found to be eligible and were approached for interviews during the baseline survey. The remaining 715 did not meet the inclusion criteria or refused to participate. A flow diagram of the sampling procedures is shown in Fig. Flow diagram of the sampling procedures following the CONSORT guideline