Introduction

Stillbirth is a global public health problem, especially in Sub- Saharan Africa (SSA) and South Asia [1–4]. The WHO explained stillbirth as fetal death (i.e., death before the complete expulsion or extraction of a product of conception from its mother) in the third trimester (≥28 completed weeks of development) or with birth weight ≥1000 g or length ≥35 cm [5–7]. It is also an indicator of the quality of care during pregnancy and childbirth; institutional deliveries are increasing but stillbirth is not well decreased in the developing world [8–11].

Globally, there were 2.6 million stillbirths, of which the majority of deaths occurred in developing countries [7]. Ninety-eight percent occurred in low- and middle-income countries including South Asia and Sub-Saharan Africa [7, 8, 12]. The stillbirth rate in sub-Saharan Africa is approximately 10 times that of developed countries (29 vs 0. 3 per 1000 births) [7, 12]. An observational multi-country study from sub-Saharan Africa showed that the magnitude of stillbirth ranges from 28.9–154.6% per 1000 [13–17]. Hence, stillbirth rates are unacceptably high in a low-middle income country.

Previous researchers have revealed that asphyxia, maternal infection, non-communicable disease, chronic illness, resident, interpregnancy interval, previous preterm birth, premature rupture of membrane, the induced onset of labor, prolonged labor (>12 hours), multiple pregnancies, mode of delivery, maternal age, place of residence, education level, parity, antenatal care utilization, place of delivery, body mass index (BMI) and anemia, previous stillbirth, uterine rupture, abruption placentae, belonging to the poorest family, antepartum hemorrhage, maternal hypertensive disorder during pregnancy, and small weight-for gestational age babies are significant predictors of stillbirth [13–29].

The stillbirth rate is an important indicator of the quality of care during pregnancy and childbirth, as well as a sensitive marker of the health-care system. Post-2015 initiatives show that stillbirths are a hidden agenda worldwide and continue to be a sustainable development goal. A target to end preventable stillbirths was included in the Every Newborn Action Plan and endorsed for 194 countries including Ethiopia on the world health assembly in 2014. The plan was set with the goal of reducing the national stillbirth rate to 12 or fewer per 1000 births by 2030 [30]. Identifying predictors of stillbirth would contribute to the realization of a global target of stillbirth reduction in one or another way.

Ethiopia is among the countries with the highest stillbirth rate worldwide [12, 30]. According to the 2016 and 2019 Ethiopian Demographic and Health Survey (EDHS) report, the stillbirth ratio was 11 and 12 per 1000 live births [31, 32]. Stillbirth is an adverse birth outcome and represents a major problem in developing countries including Ethiopia. To curb this high stillbirth rate and neonatal morbidity, identifying the predictors of stillbirth is critical for developing successful interventions and monitoring public health programs. Although certain studies have assessed the predictors of stillbirth, they failed in identify the proximate predictors of stillbirth. Besides, the inconsistent findings of the predictors of stillbirth, and the methodological limitations in previously published works are some of the gaps. Therefore, this study aimed to identify the predictors of stillbirth among mothers who had given birth in six referral hospitals in Southern, Ethiopia.

In addition to, the main importance of this study for public health is: identify the potential predictors that predispose the fetus to stillbirth conditions is very important to tackle the underlying causes and to provide immediate solutions. The findings of this study initiate different stakeholders in the health care system to design appropriate strategies and planning for the measurements to be taken to avoid those potential factors, both in health care institutions as well as in the community at large. This study is an input for health policymakers and program developers typical of neonatal and child health in the health care delivery system.

Methods and materials

Results

Socio-demographic characteristics of the mother

In this study, 138 cases and 269 controls were included with a response rate of 98.5% for both cases, and controls. The mean age of the case and controls was 28.1 and 27.2 years respectively. However, the mean age difference between the case and control groups was not statistically significant in the independent sample t-test (p = 0.23). Nearly all, 135 (97.8%) of the cases and 264 (98.1%) of the controls were married. Almost three-fifths, 113 (76.2%) of the cases and 205 (78.1%) of the controls were rural by residence. Regarding the educational status of the mother, 74 (53.6%) of the cases and 135 (50.2%) of the controls did not attend formal education. Nearly two-thirds, 90(65.2%) of the cases and 186(69.1%) of the controls were housewives by occupation. Other socio-demographic characteristics of the mothers are summarized in Table 1.

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Table 1. Socio-demographic characteristics of mothers who had given birth in South Ethiopia, 2020 (N = 407).

https://doi.org/10.1371/journal.pone.0249865.t001

Obstetrics history of mothers

Regarding antenatal care, 13.4% of mothers of controls had no antenatal care visits during the last pregnancy while 38.4% of mothers of cases had no antenatal care visits during the last pregnancy. The difference in antenatal care among mothers of cases and controls was statistically significant with the chi-square test (P-value = 0.001) (See Fig 1).

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Fig 1. Frequency of ANC visit among mothers who had given birth in South Ethiopia, 2020 (N = 407).

https://doi.org/10.1371/journal.pone.0249865.g001

Fifteen (10.9%) mothers of cases had a history of abortion while 8.9% of mothers of controls had a history of abortion. The difference was not statistically significant in the chi-square test (P-value = 0.072).

Concerning parity, (22.5%) of mothers of the cases were grand multi-parous, followed by multi-parous (60.9%) and primiparous (16.7%). Forty-four (31.9%) mothers of cases had hypertension during pregnancy while 15.6% of mothers of controls had hypertension during pregnancy. The difference in hypertension during pregnancy among mothers of cases and controls was statistically significant with the chi-square test (P-value = 0.003). Other obstetric histories of the cases and controls are summarized in Table 2.

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Table 2. Obstetrics history of mothers who had given birth in South Ethiopia, 2020 (N = 407).

https://doi.org/10.1371/journal.pone.0249865.t002

Predictors of stillbirth

Multivariable logistic regression model identified significantly associated factors with still birth which includes, women with multiple pregnancy [AOR = 2.98, 95%CI: 1.39–6.36], having preterm birth [AOR = 2.83, 95%CI: 1.58–508], having cesarean mode of delivery [AOR = 3.19, 95%CI: 1.87–5.44], having no ANC visit [AOR = 4.17, 95%CI: 2.38–7.33], and being hypertensive during pregnancy [AOR = 3.43, 95%CI: 1.93–6.06] were significantly associated with stillbirth.

The odds of stillbirth were 4.2 times higher among mothers who had no ANC visits during pregnancy compared to mothers who had no ANC visit. Mothers who had hypertension during pregnancy had 3.4 times higher odds of stillbirth compared to mothers who had no hypertension during pregnancy.

Cesarean section is a significant predictor of stillbirth. Mothers who had delivered in the cesarean section had 3.2 times higher odds of stillbirth compared to mothers who had delivered by vaginal mode of delivery. The overall model fitness (Hosmer-Lemeshow) and Omnibus test showed that the model fitted the data with a p-value of 0.883 and p-value of< 0.001 respectively. The predictors of stillbirth are summarized in Table 3.

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Table 3. Multivariable logistic regression model for predictors of stillbirth among mothers who had given birth in South Ethiopia, 2020 (N = 407).

https://doi.org/10.1371/journal.pone.0249865.t003

Discussion

Identifying predictors of stillbirth is fundamental to mitigate the problem and to help couples have a healthy baby. Though, few studies have been done to identify predictors of stillbirth, the most important predictors were not assessed. Therefore, this study assessed predictors of still birth by incorporating the most proximate factors affecting birth outcomes in the study setting. Of the variables that were assessed in this study; having no ANC visit, being hypertensive during pregnancy, having cesarean section mode of delivery, having multiple pregnancies and preterm birth had a significant association with stillbirth.

Mothers who had no ANC visits were almost four times at a higher risk of developing stillbirth than mothers who had ANC visits. This finding is consistent with those of studies conducted in Northern Ethiopia and Nepal [26, 27]. This could be because mothers who had no antenatal care visits will not receive any antenatal care services including risk assessment, care provision, and health promotion. Hence, mothers who had no ANC visits will not gain a screening opportunity for certain risk factors that are associated with antepartum hemorrhage, intrapartum hemorrhage, certain medical conditions, infection, or hypertensive disorder. If risks are found, health care providers will not have the opportunity to manage or treat specific conditions. Additionally, they could not provide counseling to mothers and families, all of which could not help to prevent stillbirth. This report also indicates that the provision of good and sufficient perinatal counseling in the MCH clinic will help to mitigate the problem of stillbirth.

The government of Ethiopia provides free antenatal care check-ups through public health facilities and has a standard protocol for antenatal check-ups [31, 32]. The 2019 EMDHS results show that 74% of women who gave birth in the 5 years preceding the survey received antenatal care from a skilled provider at least once during their last pregnancy. Four in 10 women (43%) had four or more ANC visits for their most recent live births [32]. Moreover, large disparities exist in the access to antenatal care by socioeconomic status, with women from rural residents and those with the least education have the lowest access to care in Ethiopia [32].

Hypertension during pregnancy is significantly associated with stillbirths. Mothers with hypertension during pregnancy were almost 3 times more likely to develop stillbirth compared to mothers who had no hypertension during pregnancy. This finding is congruent with those of studies conducted in Taiwan, Nepal, and England [28, 29, 35]. This is because mothers who have hypertension during pregnancy do not have sufficient blood flow to the placenta compared with mothers who have no hypertension during pregnancy. In addition to this, blood pressure falls by the second trimester in most cases but rises during the third trimester to a level somewhat above in the early pregnancy. Hence, the fetus will receive less oxygen and fewer nutrients, which in turn causes the fetus to be born a stillbirth.

Hypertensive pregnancies are responsible for 4–9% of all fetal deaths. The stillbirth rate is 5-52/ 1000 births, depending on the severity of complications from hypertension [36]. Hypertension is one of the most common medical conditions that complicate pregnancy which results in intrauterine growth retardation, intrauterine fetal death, and stillbirths [29].

Mothers who had delivered in the cesarean section were 3.2 times at a higher risk of developing stillbirth compared to their counterparts. This finding is congruent with a global survey conducted on stillbirths [37, 38]. Cesarean section carries many risks to women including blood loss, maternal inactivity, injury to organs, blood clot, death of the mother, increased risk of uterine rupture, and stillbirth. This finding suggests that health care providers should consider the potential risk of cesarean section while assessing the clinical indications for cesarean section. Cesarean section should be performed only when there is convincing clinical indications, in other words, cesarean section mode of delivery should not be considered for non-medical reasons.

Studies conducted in Denmark and West Africa also demonstrated that cesarean section is a predictor of stillbirth [39, 40]. This report implied that health caregivers working on MCH should take into consideration the possible risk of cesarean section while assessing the risk of pregnancy at the ANC clinic. The practice of cesarean section should be implemented only when there are compelling medical clues. This finding also showed that reducing the cesarean section mode of delivery could be a preventive strategy for the occurrence of stillbirth.

Mothers who had multiple pregnancies were 3 times at risk of stillbirth than mothers who had no multiple pregnancies. Studies conducted in 12 hospitals across Kenya, Malawi, Sierra Leone, Zimbabwe, and Jordan revealed that multiple pregnancies are a risk factor for the occurrence of stillbirth [13, 23]. Women with multiple pregnancies are more likely to develop preterm labor and birth, placental problems, gestational high blood pressure, gestational diabetes, preeclampsia, postpartum hemorrhage, anemia, and fetal complications including spinal Bifida, twin-to-twin transfusion syndrome, and other neural tube defects in the digestive tract and heart.

This health challenge often develops prematurely and is worse than that in gestation with one baby. It can also accelerate the early separation of the placenta (placental abruption). This in turn leads to fetal death (i.e., death before the complete expulsion or extraction of a product of conception from its mother) in the third trimester (≥28 completed weeks of gestation).

Women who had preterm birth were 3 times at a higher risk of stillbirth compared to women who had term birth. This finding is similar to those of studies conducted in England, India, and Southern Ethiopia [15, 20, 23]. A possible explanation could be that women with preterm birth are more likely to result in stillbirth which is mainly associated with trouble in breathing due to an immature respiratory system and experience prolonged pauses in their breathing, known as apnea, heart problems, temperature control problems including the absence of stored body fat of a full-term infants, and inability to generate enough heat to counteract what is lost through the surface of their bodies, immune system problems, and infection. This in turn causes stillbirth (a baby born with no signs of life at or after 28 weeks gestation).

The limitation of this study is that it does not incorporate some of the variables that are addressed in the community, such as wealth index, nutritional status, and cultural aspects. Therefore, other scholars should consider those situations, and it is also very important if they supplement or triangulate with a qualitative study to dig out untouched aspects. Thus, the readers should consider the limitations of this study while interpreting the finding, and the other scholars will do more to overcome those limitations. The finding of this study gives an overriding reputation to tackle factors determining stillbirth, which leads to stillbirth and predisposing factors for stillbirth.

Conclusions

In this study we found that being hypertension during pregnancy, having cesarean section mode of delivery, having no ANC visits, having multiple pregnancies and preterm birth were independent risk factors associated with still birth. The predictors of stillbirth identified are manageable and can be amenable to interventions. Therefore, appropriate prevention strategies during antepartum and intrapartum care should be focused on to tackle these risk factors of stillbirth. Strengthening maternal antenatal care utilization should be encouraged by providing appropriate information for the mothers. There is a need to identify, screen, and critically follow high-risk mothers: those who had different complications during pregnancy, those who faced hypertension during pregnancy, those who identified as multiple pregnancies, and those undergoing cesarean section due to different indications.

Supporting information

Acknowledgments

We would like to acknowledge Wolkite University College of medicine and health science for approving the research project. Furthermore, our special appreciation goes to data collectors for their genuine effort to bring reliable data. Finally, we would like to wholeheartedly acknowledge study participants without them this work could not be realized.