2.1. Overview of adverse pregnancy outcome
The burden of adverse pregnancy outcomes (APOs), which includes both stillbirth and abortions, is substantial in both developed and developing countries. Globally, out of an estimated 210 million pregnancies, 75 million end in abortions or stillbirths. Every day more than 7200 babies are stillborn, and 2.6 million stillbirths occurred worldwide in 2009 and majority of all stillbirths occur in low-income countries. Study revealed that, a high correlation between stillbirths and maternal mortality; 28 countries reporting the highest stillbirth rate contributed the highest maternal mortality rate worldwide (Löfwander, 2012). The world health statistics revealed that the rate of stillbirth globally was 19 per 1000 deliveries, in the African region it was 28 per 1000 deliveries, 26/1000 for low income countries, 21/1000 for low middle income countries and less than 1% for the high income countries. More than any other region, sub-Saharan Africa is home to the highest number of child deaths roughly 3 million in 2015 (World health organization, 2015). In Ethiopia, the world health statistics revealed a stillbirth rate of 26/1000 deliveries which is third highest in the east African countries next to Djibouti and Somalia (with stillbirth rates of 34 & 30 per 1000 births, respectively (Engmann et al., 2012).
The number is a small decline of 1.1% per year over the previous years (Löfwander, 2012). In addition, study conducted Uganda reported an adverse pregnancy outcome (abortion or stillbirth) was accounted for 10.8 % pregnancies (Gershim et al., 2015). The rate of experiencing stillbirth among women of childbearing age was about 25.5 per 1000 deliveries in Ethiopia (Analizi, Kidanemariam and Habtamu, 2017)Complications or problems associated with adverse pregnancy outcome can lead to severe maternal morbidity and mortality. Furthermore, over 830 women died due to preventable causes related to pregnancy and childbirth each day in 2015, largely from preventable or treatable causes.

2.2. Factors affecting adverse pregnancy outcome
Different factors contributed for adverse pregnancy outcomes. Numerous studies have found that socioeconomic status and income inequality are correlated with adverse outcomes. For Self-employment among the partners of the respondents was associated with poor pregnancy outcomes (unadjusted OR 2.885) compared with employed partners. Investigating the socioeconomic position and the risk factors of preterm birth, (Morgen et al., 2008). Undertook a study within the Danish National Birth Cohort. Ugwuja (2011) studied the impact of socioeconomic status on pregnancy outcomes on Nigerian women. It was pointed out that several studies on socioeconomic status impact on pregnancy outcomes produced conflicting results. In addition, the health status of a woman before and during pregnancy is a key determinant of pregnancy outcomes (Abu-Saad and Fraser, 2010).
Gershim et al. showed risk of adverse pregnancy outcome is increased with age of mother, non- attendance of antenatal care and proximity to the road. Abortion and stillbirth risk reduced with increasing parity (Gershim et al., 2015). Other study also reported, age group, type of place of residence, antenatal care visit and delivery place were found to be statistically significant factors for experiencing stillbirth among regions (Analizi, Kidanemariam and Habtamu, 2017) . (Padhi et al., 2012)found that the most common causes of adverse outcomes of pregnancy among black teenagers are lack of sex education, the absence of reproductive health services to vulnerable members of the community, poor access to primary health care and poverty (Wealth Index) and unemployment, illiteracy, as well as the lack of advice counselling services by suitably trained social workers. Abortions often cause the loss of fetus and permanent injury on women. Based on reports issued by the Integrated Regional Information Network.
Antenatal care utilization:
During pregnancy antenatal care visits (ANC) plays an important role. Opportune and adequate antenatal care is generally acknowledged to be an effective method of preventing adverse outcomes in pregnant women and their babies (Joyce, Jebet, 2012). Survey in Kenya showed that Respondents who never received antenatal care during their pregnancy were associated with poor pregnancy outcomes. Study done in Wollo showed that, Mothers who didn’t attend ANC were more than 3 times to have adverse pregnancy outcome, than mothers who attended ANC follow up, OR = 3.4 (EsheteA., 2013) .The same study done in Gondar showed that lack of antenatal care follow up (OR: 9.7) is significantly associated with still birth (Adane A., 2014). Mothers who didn’t attend ANC were more than 3 times to have poor birth outcome, than mothers who attended ANC follow up. In the binary logistic analysis done in Hawassa University Hospital, southern Ethiopia, both the crude and adjusted analysis showed that the stillbirth rate was highest among mothers who had no ANC follow up(Bayou and Berhan, 2012).
Anemia level:
World health organization (WHO) defines anemia as a low blood hemoglobin responsiveness. Anemia during pregnancy is one of the most mutual indirect obstetric cause of adverse pregnancy outcome in developing countries. It is responsible for poor maternal and fetal outcomes. A limited number of studies were conducted on anemia during pregnancy in Ethiopia, and they present inconsistent findings. Anemia is a global health problem for women (Benoist et al., 2008) Women with severe anemia are particularly at risk and have a 3.5 times greater chance of dying than women without anemia (Lule et al., 2005).
Body mass index (BMI):
In 2009, the Institute of Medicine classified body weight based on body mass index (BMI) as underweight (BMI 3 years general secondary school, intermediate vocational training and 1st year higher vocational training, mid-high :higher vocational training and Bachelor’s degree, and high :higher academic education and PhD. Association between education level of pregnant women and adverse pregnancy outcomes was examined using logistic regression analysis with high education as the reference group. Study results showed that women with a low educational level have a nearly two times higher risk of experiencing adverse pregnancy outcome compared to women with a high educational level. A more discreet decline appeared between primary education and other levels of education. The study therefore concluded that there was a possible major reduction of stillbirth by elevating education levels from none to primary level.
Marital status:
(Kalilani-Phiri et al., 2015); (Lema, Mpanga and Makanani, 2002)in their facility-based studies observed that there was a higher prevalence of married women (78.7% – 81.0%) of all women presenting for PAC than single, separated, widowed or divorced women. However, majority of the Malawian studies did not indicate whether abortions were induced or spontaneous, except (Lema, Mpanga and Makanani, 2002) who reported that 86.3% of women who interfered with index pregnancy were single. Similar findings were reported by (Levandowski et al., 2012). After controlling for age, residence, region and education, unmarried mothers were 6.8 (95%CI 4.7-9.8) times more likely to report interference than married mothers. This study also demonstrated that married young adults were 2.8 times more likely to report contraceptive use at time of pregnancy than unmarried young adults.
In Ethiopia also there are large differences in levels of adverse pregnancy outcome by11 regions. Study conducted by (Analizi, Kidanemariam and Habtamu, 2017) This might be due to methodological differences, in which the grouping variable, region, was significantly associated with experiencing stillbirth so that we used multilevel analysis, and time gap between the current and earlier surveys, in which some of the factors might be improved. But further studies are required to confirm these findings. The rate of experiencing stillbirth in Tigray, Amhara, Oromiya, SNNP, Gambela, Harari and Dire Dawa were not significantly differing from that in Addis Ababa. This might be because of most of these regions are similarly developed as Addis Ababa. Women who live in Afar, Somali and Benishangul Gumuz regions were significantly more likely to experience stillbirth than those women living in Addis Ababa which might be because of they were disadvantaged regions in the past controls. Experiencing stillbirth in Benishangul- Gumuz was 2.451 times more likely than that in Addis Ababa city. Somali region had the highest (5.26%) percentage of experiencing stillbirth followed by Tigray region (3.73%). Gambela and Addis Ababa had the lowest percentages (1.49%, 1.54%) respectively, for experiencing stillbirth in Ethiopia.