This study assessed trend of unintended pregnancy, abortion and associated factors among adolescents in Ethiopia from 2000 to 2016. The overall prevalence of unintended pregnancy was 34.0% among adolescents in Ethiopia. Studies done in sub–Saharan Africa countries including Ethiopia also showed that unintended pregnancy rate in sub–Saharan Africa remains high, especially among adolescents [4, 28, 29]. The prevalence of unintended pregnancy among Ethiopian adolescents decreased significantly from 41.4% in 2000 to 25.1% in 2016, potentially reflecting the impacts of the national reproductive health interventions in Ethiopia . Factors associated with a lower likelihood of unintended pregnancy among adolescent girls in Ethiopia included being aged above 17 years old and being married. While, higher parity, resided in large central and metropolis regions were significantly associated with higher odds of untended pregnancy.
The prevalence of abortion also decreased significantly from 8.3% in 2000 to 4.1% in 2016. Belonging to middle and rich wealth households, having unintended pregnancy, female head households and being rural residents were factors significantly associated with lower likelihood of abortion among adolescents in Ethiopia. These reduction may be attributable to the relatively high maternal health service utilization like modern contraceptive utilization (35%) ) in 2016  compared to (6%) in 2000 . These findings reflected that reproductive health interventions targeting the reduction of unintended pregnancies and induced abortion among adolescents should be strengthen more in order to reduce unintended pregnancies, abortion related mortality and morbidity, improve adolescent health and permitting adolescents to attain their economic potential [5, 31–34].
This study showed that adolescent girls aged below 18 years old had higher odds of having unintended pregnancy. Similarly, studies conducted in Africa indicated that the risk of unplanned pregnancies decreases with age that older mothers had lower odds of unintended pregnancy in developing countries [35–40]. This might be due to older women had relatively better knowledge on contraceptive methods to prevent unintended pregnancy and lower contraceptive failure rate [35, 41]. Moreover, as they are getting older, women might also become more literate about the importance and accessibility of reproductive or maternal health services. In addition, this could be also as the results of older women are less likely to engage in risky sexual behaviors such as unprotected sexual intercourse and sex under the influence of drinking alcohol[42, 43]. However, other literatures revealed a negative relationship between age and unintended pregnancy[37, 44, 45]. This finding might be related to the fact that adult women might already have the desirable number of children and considered any additional pregnancy as mistimed or unwanted.
In this study, education was no significantly associated with untended pregnancy. There was no agreement across researches regarding the impact of the level of education on the risk of having unintended pregnancies. A systematic review on prevalence and determinants of unintended pregnancy in Sub–Saharan Africa revealed that the outcomes ranged from reporting no association with level of education and odds of having unintended pregnancies in Nigeria, South Africa, Ethiopia, and Kenya, through an increased risk of reporting the last pregnancy as unintended as the level of education increases in the Democratic Republic of Congo and Ethiopia [49, 50], to an increase in the level of education being protective against unintended pregnancies in Nigeria, in Tanzania and in Ethiopia. Researches that analyzed demographic health survey data also found discordant findings in Ethiopia ; in the study by Tebekaw, education was protective against unintended pregnancies , while the other study found no association between education and unintended pregnancy. A study done in Nairobi also found that education was protective against having an unintended pregnancy, with a 10% decrease in the risk of having an unintended pregnancy .
In this study, married women had significantly lower odds of untended pregnancy compared to those who were unmarried. This find is consistent with studies conducted in Ethiopia [6, 29, 54–56], in Kenya and in South Africa; reported that unmarried mothers were at higher odds of unintended pregnancy. The potential reason is that unmarried adolescent girls may unintentionally participate in sexual activity and this is most likely unwanted if the pregnancy is occurred. Additionally, our culture and community might cause a significant influence on unmarried women not to use contraceptive because of sex is not recommended before the women became married. In addition, this could be due to the fact that married mothers are less likely to engage in risky sexual behaviors such as unprotected sexual intercourse and sex under the influence of drinking alcohol [42–44]. On the other hand, unmarred adolescent girls could engage in sexual activity for pleasure. Therefore, if pregnancy occurs it is more likely to be unintended. Furthermore, they are less likely to use contraceptive methods[56, 58]. Other reasons could be difficulty in accessing contraception, not having adequate financial and social support to provide for their unborn child .
The study also indicated that adolescent mothers who had relatively higher parity experienced more risk of having unintended pregnancy. This finding is supported by researches done in Ethiopia[31, 56, 59], in Ghana and in Pakistan , that reported multiparous and grand multiparous mothers had higher odds of unintended pregnancy compared with primiparou women. Similarly, studies from Brazil and USA have reported that mothers who have more alive children are more likely to experience an unintended pregnancy . The possible explanation might be high parity woman might already have adequate children with a decreasing intention for the next pregnancy. This might be also due to mothers with higher parity might be busy in caring their children and family and this affects their getting of information, accessing and utilization of maternal health services such as contraceptive methods which in turn end up with unintended pregnancy. In addition, it might imply the gaps in provision of contraceptives counseling and education .
Evidence has shown that prevalence of unintended pregnancy differs across socioeconomic levels at national and subnational levels [4, 28, 29]. This study also found significant variations of unintended pregnancy rate across regions in Ethiopia that adolescent girls from large central and metropolitan regions had higher likelihood of unintended pregnancy. This regional difference of unintended pregnancy prevalence is congruent with research findings from Ethiopia [23, 27], Kenya , and Ghana . This could be due to pregnancies might be appreciated and accepted in small peripheral regions and mothers in this region did not think about unintended pregnancy. Nevertheless, women in metropolitan and large central regions may be busy because of their intention to advance their socio-economic status and mostly their pregnancies are more likely to be unintended [28, 29]. These variations a cross regions reflect the significance of disaggregated data for evidence-based policymaking and program design and context-specific interventions are required in order to reduce unintended pregnancy and associated abortion among adolescents in Ethiopia.
Adolescents from middle and rich wealth households had significantly lower rate of abortion compared to those from poor wealth households. This finding is supported by previous researches evidence that women with lower income had higher rate of induced abortion than those with higher income [61, 62]. Finding from the EDHS Surveys have shown that modern contraception use increases sharply with wealth, ranging from 20% in the lowest wealth index to 47% in the highest wealth index quintile. Hence, the low contraceptive utilization among adolescents with lower economic status may account for the higher odds of abortion . It might also due to financially not prepared to raise their unborn child. Therefore, women in poor wealth households may get an induced abortion in order to limit births due to economic, demographic and social reasons . Abortion was also less likely to occur among women whose husband had occupation [45, 67]. This might be because employed husbands have a positive attitude in avoiding pregnancy termination by increasing their economic status and women might get frequent health institution visits and health information about consequences of pregnancy termination. Adolescents from poor income families may be also more risky to sexual coercion and rape that can lead to unintended pregnancy and induced abortion  .
Furthermore, adolescents from female headed households experienced significantly lower rate of abortion compared to those from male headed households. Likewise, previous studies also documented that female-headed households were less likely to experience unwanted adolescent pregnancy[4, 51]. This might be due to adolescent girls from female headed households would have access to information where to get the services and perhaps may be they had their own income to raise their child, as a result women might get frequent health institution contact for antenatal care, delivery and health information about consequences of pregnancy termination. And it could be also due to relatively better level of reproductive health knowledge and access to family planning services, freedom of decision making on reproductive matters among female head households compared with male headed household counterparts [45, 66].
In this study, the likelihood of abortion among women who had unintended pregnancy was significantly lower than women who had intended pregnancy. A study conducted in West Arsi Zone, Ethiopia also showed a negative relationship between abortion history and unintended pregnancy . Possible explanation may be even though women who had unintended pregnancy tend to avoid unwanted pregnancies by inducing their current pregnancy, they might still lack the self-rule to make decisions about their pregnancy intention. As it is the case with many other areas of reproductive health, husbands appear to be the primary decision makers with consider to pregnancy . Moreover, studies also indicated that previous unintended pregnancies and previous abortions were reported to be risk factors for subsequent unintended pregnancies . This could be an indication of inadequate sex education, contraception education, or sub–optimal post-abortion counseling among women with previous unintended pregnancies
Place of residence was also a significant factor associated with abortion. Adolescents from rural areas also had lower rate of abortion compared to urban counterparts. This finding was supported by studies conducted in Ethiopia.This might be because adolescents from urban areas are exposed to different factors that make them risky to sexual behaviors that will end in unwanted pregnancy and induced abortion. Urban girls have a lot of access to addiction of stimulants and alcohol than rural girls as well as better access to abortion services. Moreover, adolescents from rural areas might also fear to induce abortion believing that terminating pregnancy as a sin due to their religion believes .