High blood pressure and associated factors among pregnant women attending antenatal care (ANC) visits at Dilla University Referral Hospital, Ethiopia: a cross-sectional study

High blood pressure during pregnancy can lead to preterm birth and preeclampsia, among other issues for both the mother and the fetus, particularly in low- and middle-income countries including Ethiopia. Thus, the purpose of this study was to identify the contributing factors and their marginal effects on high blood pressure among pregnant women attending antenatal care (ANC) visits at Dilla University Referral Hospital. A hospital-based cross-sectional design was applied to study the blood pressure of 204 sampled pregnant women from November 2023 to October 2024. Pregnant women with chronic hypertension and had fewer than four blood pressure readings were excluded. According to the 2017 AHA/ACC guidelines, blood pressure was categorized as normal, elevated, stage I hypertension, and stage II hypertension. Descriptive statistics (frequency and percentage) and ordinal logistic regression model were used for analysis. The association between each explanatory variable and a single blood pressure level category was presented using the marginal effect. The Brant test was used to verify the parallel line assumption under the ordinal logistic regression model. The proportional odds assumption was satisfied, and then significant factors for high blood pressure were identified by using the proportional odds model. Of the 204 pregnant women, 116 (56.86%) had normal blood pressure, 36 (17.65%) had elevated blood pressure, 32 (15.69%) had stage I hypertension, and 20 (9.80%) had stage II hypertension. The analysis showed significant associations between blood pressure categories and HIV status (OR = 0.20; p-value = 0.001), parity above 5 (OR = 13.4; p-value = 0.001), multiple pregnancy (OR = 3.94; p-value = 0.008), mother age (OR = 5.9; p-value = 0.001), family size of greater than 5 (OR = 12.5; p-value = 0.001), and iron taking status (OR = 0.26; p-value = 0.001). Older age, larger family size, multiple pregnancies, and higher parity increased the likelihood of blood pressure, while iron supplementation and higher educational level decreased the likelihood of blood pressure. High blood pressure remains a major public health concern among pregnant women attending antenatal care (ANC) visits in Dilla University Referral Hospital. Promoting maternal education and iron supplementation, and providing closer monitoring for high-risk mothers perhaps help reduce hypertension-associated complications during pregnancy.