Background
Little is known about factors contributing to inequities in antenatal care use in Ethiopia. We aimed to assess inequities in the use of antenatal care on the basis of area of residence, administrative region, economic status and education.

Methods
This study was based on data from repeated cross-sectional surveys carried out by Measure Demographic and Health Survey and Central Statistical Authority of Ethiopia. The surveys were conducted in February-June 2000, April-August 2005, and December 2010-June 2011. The surveys employed a cluster sampling design to select a nationally representative sample of 15–49 year-old women. The main outcome variable was at least one antenatal care visit for the last live birth in the 5 years preceding the surveys. Statistical analysis was completed by applying the sampling weights in order to consider the complex sampling design.

Results
A total of 7978, 7307 and 7908 weighted number of women participated in the three surveys, respectively. The rate of antenatal care coverage in Ethiopia has increased from 26.8% in 2000 to 42.7% in 2011. The odds of antenatal care use were 2.4 (95% CI: 1.7-3.2, p?<?0.0001), 1.6 (95% CI: 1.2-2.2, p?=?0.003) and 1.8 (95% CI: 1.3-2.6, p?=?0.001) times higher among women from urban areas than those from rural areas at the three time points, respectively. The odds ratio of antenatal care use among women with secondary or higher education compared with women of no education increased from 2.6 (95% CI: 2.0-3.4, p?<?0.0001) in 2000 to 5.1 (95% CI: 2.8-9.4, p?<?0.0001) in 2011. Moreover, the odds of use among women from the richest households at the three time points were 2.7 (95% CI: 2.1-3.6, p?<?0.0001), 4.4 (95% CI: 3.3-6.0, p?<?0.0001), and 3.9 (95% CI: 2.8-5.5, p?<?0.0001) times higher compared with their counterparts from the poorest households. Furthermore, we have observed a wide regional variation in the use of ANC in Ethiopia.

Conclusions
The wide inequities between urban and rural areas, across economic and educational strata in the use of antenatal care highlight the need to put more resources to poor households, rural areas, and disadvantage regions. We suggest further study to understand additional factors for the deep unmet need in rural areas and some regions of Ethiopia.