Background: Antenatal Care (ANC) services utilization during the first trimester is very important for risk identification, and prevention and management of pregnancy-related diseases. However, the ANC services utilization during the first trimester in Ethiopia is very poor. Likewise, there has been no research conducted in Boke Woreda on determinants of ANC services utilization. Therefore, the aim of this study was to identify determinants of ANC services utilization during the first trimester in Boke Woreda, Ethiopia.Methods: A health facility based unmatched case-control study design was conducted in Boke Woreda, Ethiopia. The data was collected using pre-tested and structured questionnaires through interviews. Data analysis was done by SPSS for Windows Version 20.0. Bivariate and multivariate logistic regressions were conducted. P-value <0.05 was used to declare statistically significant variables.Result: All selected pregnant women (339 participants) were interviewed with 100% response rate. ANC services utilization was associated with maternal age at less than 26 years (AOR=3.87,95% CI:1.57,9.51), women travelling at lower than 30 minutes to the health facility (AOR=3.26,95% CI:1.46,7.26), Women who experienced one to two number of pregnancy (AOR=5.01,95% CI:1.74,14.41), Pregnant women who had zero to two birth before (AOR=3.93,95% CI:1.35,11.41), and previous ANC service utilization history (AOR=2.52,95% CI:1.03,6.20). Besides, ANC service utilization was also positively associated with pregnant women who were supported by their family (AOR=3.28, 95%CI: 1.18, 9.06), service waiting time at less than 45 minutes (AOR=6.17, 95% CI: 1.83, 20.73), and pregnant women who were welcomed by health workers (AOR=7.81, 95% CI: 3.19, 19.09).
Conclusion:Maternal age, travelling time to the health facilities, client welcomed appreciation, maternal knowledge on ANC services, previous service utilization, parity, gravidity, and service waiting time were found to be the determinants of antenatal care services at first trimester. Therefore; Policy makers and stakeholders in the area have to focus their intervention on the identified factors in order to improve the ANC service utilization in the first trimester.