Amniotic fluid is the clear liquid in the uterine cavity that encircles the fetus from the first weeks until the late weeks of gestation. Throughout pregnancy, the fetus is almost the sole source of it. It has multiple physiological, biochemical, and physical functions, which have critical roles in growth and development in utero (1). Meconium is a thick, sterile, greenish material found in the intestine of a growing fetus around the last trimester of pregnancy. The color of meconium is secondary to the bile content, and meconium comprises intestinal desquamated cells, mucous, fatty materials, lanugo, blood group-specific glycoproteins, intestinal secretion, gastrointestinal mucin, and fatty material from the vernix caseosa (2, 3).

Fetal defecation into the amniotic fluid cavity usually starts from the early first trimester of gestation and progressively becomes infrequent after 20 weeks, with parallel maturation of anal sphincter innervation; otherwise, commonly, fetal defecation happens 12 h–24 h after delivery (4, 5). However, a stressful condition in utero can induce the passage of meconium due to increased bowel movement and anal sphincter relaxation secondary to vagal stimulation associated with cord compression or sympathetic impulse during the hypoxic state.

Additionally, 20%–30% of fetuses with meconium-stained amniotic fluid (MSAF) have neurologic and respiratory depression at birth, which indirectly indicates chronic insult (6–9). The incidence of MSAF can vary based on gestational age, and according to multiple studies, it ranges from 5.1% in preterm fetuses to 27.1% in post-term fetuses, which has similar reports from low-resource countries; however, the prevalence MSAF among mothers who underwent emergency cesarean section has not been studied (10–18). Although meconium is sterile, the mucopolysaccharide content is fertile ground for the growth of bacteria, especially Escherichia coli (19).

It has an inhibitory effect on the phagocytosis of polymorphonuclear cells. Moreover, the meconium content can induce pronounced inflammatory reactions in fetal and neonatal lungs, which causes chemical pneumonitis, alveolar collapse, and cellular apoptosis (19, 20). Furthermore, depending on the thickness of the meconium, it can obstruct the upper airway tract after delivery during the first breath of life. According to studies, the rate of perinatal asphyxia was 20%–33% (21), and meconium aspiration syndrome (MAS) was 2%–10% in infants born with MSAF (21). Of the cases with MSAF, there were deaths (4.22%), mechanical ventilation (29.7%) requirements, and pneumothorax (11.53%) (9, 13, 16). Therefore, it has a significant effect on neonatal mortality and morbidity (14–18, 22).

Ethiopia is one of the low-income countries with the highest burden of maternal, neonatal, and infant mortality and morbidity in the world. Recent evidence shows that Ethiopia still faces a considerable burden of newborn morbidity and mortality despite the substantial improvements in access to and availability of obstetric caregiving facilities (18, 23). The neonatal mortality associated with meconium aspiration syndrome is 3%–5%. There are controversial mechanisms such as airway obstruction, alveolar or parenchymal inflammation, impaired surfactant production and function, infection, and direct toxicity of meconium constituents. It has significant adverse health complications like the need for mechanical ventilatory support (43.1%), respiratory and metabolic acidosis (30.6%), pulmonary hypertension (11.1%), and hypoxic-ischemic encephalopathy (29.2%) (18, 22, 24). The pooled prevalence of perinatal asphyxia is around 24% according to a systematic review, and MSAF is one of the strong risk factors responsible for this high prevalence (25). Perinatal asphyxia is one of the complications associated with MSAF, which has adverse health consequences like neonatal death, encephalopathy, respiratory, and other organ complications (26).

There are a variety of factors associated with the prevalence of MSAF, according to multiple studies across the scientific world, including different Ethiopian studies. Most of them are intrapartum-related, such as labor duration, fetal distress, obstructed labor, and the mechanism of the onset of labor; obstetric complications like preeclampsia, post-term, and others (6, 10–14, 18, 27–29). So, studying these factors in detail has a substantial impact on identifying and implementing strategies to improve obstetric care; thereby, the contribution of MSAF to neonatal morbidity and mortality will progressively be controlled.

Finally, there is a shortage of data on factors associated with MSAF in low-resource areas, especially after an emergency cesarean section. MSAF in the early phase of labor is becoming one of the commonest indications for emergency cesarean sections in contemporary obstetric practice because of its aforementioned adverse complications in neonatal health outcomes (13, 16). Compared to clear amniotic fluid, mothers with MSAF have a higher preponderance for emergency cesarean sections (30).

While there are numerous studies focusing on various routes of delivery, to the best of the authors’ knowledge, there has been no study specifically examining the prevalence of Meconium-Stained Amniotic Fluid (MSAF) following emergency cesarean sections. Therefore, the primary aim of this study was to assess the prevalence of MSAF among mothers undergoing emergency cesarean sections and the secondary aim was to identify the factors associated with MSAF in these cases. Furthermore, most studies do not include institutionally related delays as a factor, but those have a negative impact on obstetric and neonatal outcomes in low-income countries. Hence, this study included those delays as a factor, as there is also no study that has been done to identify factors after emergency cesarean delivery in the area.

The prevalence of meconium-stained amniotic fluid is 31.4%, which is relatively higher than in other studies in different parts of the world (10–12, 18, 22). The reason for this higher prevalence is that the study participants are mothers with emergency cesarean sections after the onset of labor, unlike the above studies, which included all mothers regardless of the route of delivery. This finding aligns with other scientific results from multiple studies, which showed that MSAF was strongly associated with an increased cesarean section rate (13, 16, 17, 22, 30), as well as being in labor, which is a strong risk factor for MSAF (31). Since the study participants are mothers for whom emergency cesarean sections were performed for different obstetric indications, a higher prevalence of MSAF is expected. Furthermore, this study showed that labor dystocia, such as cephalopelvic disproportion and obstructed labor, is strongly associated with the prevalence of MSAF. Pregnant mothers with CPD and obstructed labor have 2.6- and 24.6-times higher odds of having MSAF compared to mothers without dystocia. Technically, these labor abnormalities are related to a prolonged duration of labor, which is one of the factors associated with MSAF in this study.

The mothers with labor durations greater than 24 h have 5.44 times higher odds of developing MSAF than those with labor durations less than 24 h. Studies across the globe associate MSAF with labor abnormalities (dystocia) (11, 12, 14) as well as prolonged durations of labor (10, 11, 13, 31), which are the same as our findings. Hence, it has been proposed that the level of cortisol, higher during labor, is critically involved in stimulating bowel movement in utero, and the labor itself has an impact on stimulating bowel movement. Fetal cortisol levels rise in fetal plasma during labor, influencing the induction of intestinal motility. This was demonstrated in pregnant monkeys, where intra-amniotic injection of glucocorticoids led to the release of meconium (32). Since the aforementioned labor abnormalities are associated with prolonged labor, they predispose the fetus to stressful conditions that subsequently induce the release of meconium in utero (7, 8, 33).

Additionally, this study identified fetal heartbeat abnormalities, like tachycardia and bradycardia, as one of the determinants for MSAF. According to the findings, those mothers with fetal bradycardia and tachycardia are at a 2.0 and 3.5-fold risk of having MSAF when we compare them with those who have a normal fetal heartbeat. This finding is similar to various research (10, 12, 14–17). The proposed explanation for the release of meconium is that hypoxia in utero results in parasympathetic stimulation of bowel movement with subsequent release of meconium into the amniotic cavity (6, 29). Thus, fetal heartbeat abnormalities are a reflection of low fetal blood pH in utero.

According to this study, primigravida are 3.6 times highly likely to have an association with the prevalence of MSAF. This finding is supported by various studies which indicate that not having previous vaginal performances is a risk factor for MSAF (12, 17, 34). Based on detailed sociodemographic studies, however, the reason for the above finding is not clearly understood. But the likely mechanism is that primigravidity has an association with prolonged labor, especially the second stage than multigravidity; therefore, it has an indirect effect on MSAF (1, 35).

Obstetric complications and a history of previous cesarean sections are negatively associated with the study's outcome, except for eclampsia, which is positively associated with MSAF. In this study, pregnant women with obstetric complications, except for eclampsia, and a history of previous cesarean sections are 6.8 and 3 times less likely to have MSAF, respectively, than their counterparts. Among all obstetric complications, however, eclampsia had eight times higher odds of developing MSAF compared to those who did not. Despite the above results in this study, most literature associates obstetric complications as a predisposing factor for MSAF (10–12, 14, 15). The reason for this discrepancy may be that this study was conducted at tertiary hospitals where senior experts were directly involved in the management of obstetric complications, ensuring that pregnant women with obstetric complications were followed strictly and managed early with a low threshold for interventions.

The new finding in this study is the impact of institution-related factors like place of referral, the time taken to reach the managing health institution, and the time taken between the decision to delivery on the presence of MSAF. The pregnant women referred from the health center were more than five times more likely to have MSAF than those from the private clinic, where there was a strict follow-up and early referral. In the Ethiopian health structure, the health center is one of the lowest units, with a relatively low level of professionals and a lack of resources to diagnose as well as manage obstetric complications. On top of the above hurdles, health centers are commonly far away from referral hospitals, resulting in long-duration referral times. Accordingly, this study further strengthens the above facts by showing that pregnant women with a referral duration greater than 1 h are fifteen times more likely to have MSAF than those with less than one hour.

Moreover, the additional factor identified during this study is the interval between decision and delivery; as the interval increases to more than 60 min, the likelihood of developing MSAF becomes 1.36 times higher than that of less than 30 min. Globally, neonatal survival is increasing due to extensive work done in expanding advanced neonatal care during the past decades, although such improvement is not as expected in low-income countries (26). There is a lot to do in low-income countries through the expansion of advanced neonatal care service deliveries, infrastructure building, accessible roads, ambulance services, and resource supply, along with rigorous health professional training.

In this study, the prevalence of MSAF is relatively high. There are different factors associated with MSAF, including intrapartum-related factors like the duration of labor, obstructed labor, and cephalopelvic disproportion. Moreover, other factors include maternal obstetric complications, previous cesarean sections, and eclampsia. The last group consists of institution-related factors like the time to reach the managing institution, the place of referral, and the duration from decision to delivery. Therefore, an improvement in the quality of antenatal and intrapartum care is strongly recommended; professional development training and skill empowerment at health centers, which can provide comprehensive obstetric care, and strengthening the referral system are also suggested.