Preterm delivery is defined by the World Health Organization (WHO) as delivering a baby before it achieves normal gestation or before term pregnancy, which implies before the 37th week of pregnancy or within 259 days after a woman's last normal menstrual period (LNMP) (1).

The purpose of this study is to assess the magnitude of preterm birth and its associated factors among mothers who gave birth in the Debre Berhan comprehensive specialized hospital.Littele is known about the magnitude of the problem in the study area. This specific hospital was chosen because the hospital serve as a referral center and has resources for preterm birth infrastructure and facilities in the north shoa zone of Amhara regional state of Ethiopia all other hospitals in the zone are primary hospitals and they refered a preterm birth baby to the Debre Berhan Comprehensive specialized hospital.

Preterm birth affects over 15 million babies worldwide, resulting in substantial economic expenses and lost productivity as a result of protracted stays in Neonatal Intensive Care Units after admission, as well as increasing long-term health needs due to lifelong disability (2).

Preterm births are caused by spontaneous labor in two-thirds of cases, and labor is terminated for fetal or maternal reasons in one-third of cases. Furthermore, according to World Health Organization data, real rates of preterm birth in Africa and Asia have increased more than expected (3, 4) Preterm birth was more common in underdeveloped nations, notably in Sub-Saharan Africa, and had more long-term repercussions for newborns, including developmental delays, serious health risks, and a significant socioeconomic burden, which included their families (5).

This early delivery is the leading cause of infant sickness and mortality in Ethiopia, according to the Ethiopian Demographic Health Survey (EDHS 2016); nonetheless, it is an avoidable health concerns (6).

Preterm birth, also known as prematurity, has resulted in the world's worst living conditions with significant economic and psychosocial consequences. For instance, in the United Kingdom, preterm infants accounted for 75% of Neonatal Intensive Care Unit (NICU) admissions, which can be a signal that a problem that can be considered a problem in developed countries as well (7).

In sub-Saharan Africa, more than 60% of newborns are born prematurely, resulting in huge productivity losses and poor health outcomes. Preventing the burden of prematurity among newborn babies remains a major challenge, particularly in developing countries, and preterm babies are more vulnerable to other illnesses and are the second leading cause of infant mortality; therefore, efforts to prevent prematurity should be increased across the routine healthcare system (8, 9).

Preterm birth is a leading cause of numerous medical difficulties, as well as unquantifiable emotional and psychosocial repercussions, all of which contribute to a lower quality of life for both the child and their family. Preterm birth prevention and treatment, on the other hand, did not reach the poorest and most vulnerable areas, where the burden was the greatest (10, 11).

Preterm birth is caused by a variety of factors, including maternal and sociodemographic characteristics, obstetric history, medical factors, and newborn biological characteristics, such as twin pregnancy and congenital anomalies. However, one-third of neonatal deaths are caused by preterm birth, indicating that further research is needed to reduce the burden of this issue (12).

Regarding the magnitude of preterm birth, according to countries’ profiles, 11% of the babies worldwide were born too early, which contributed to 15 million premature babies in number; for example, although the United States and Brazil rank among the top ten countries with the largest level of preterm births, 60% of preterm births still occur in Sub- Saharan Africa, and a cross-sectional study conducted in Iran, Brazil, Pakistan, Eastern Ethiopia and Kenia reported that the prevalence of preterm birth was 5.1%, 11.5%, 21.64%, 12.3%, 18.3%, respectively (13–18).

In Ethiopia, in a study conducted at Jimma University Specialized Hospital, the prevalence of preterm birth among neonates was found to be 25.9%, and at Shire Suhl General Hospital, as well as another study conducted at Axum and Adwa Towns Public Hospital, the prevalence of preterm birth was 16.9% and 13.3%, respectively preterm birth was found to be 16.15 percent in Addis Ababa Healthcare Facilities (19–22).

Regarding Factors associated with preterm birth, studies conducted in different parts of the world reported that educational level, place of residence, marital status, income level, family size, the interval between birth, medical check-ups, high blood pressure, preeclampsia, and type of pregnancy (multiple pregnancies) were variables that have a relationship with preterm birth. In addition, method of delivery like operation (cesarean section) or normal vaginal delivery, anemia, and age over 35 years have been associated with different premature births depending on the causes of premature birth and can be viewed as multifactorial or have many factors (16, 23–29).

Regarding Medical-related factors, cross-sectional research conducted in Axum and Adwa found that exposure to malaria during pregnancy, as well as the occurrence of chronic diseases such as Diabets Melitus (DM) and heart problems, was correlated with preterm birth, while another study conducted at the Debre Tabor Health Institute found that being anemic, HIV positive, and having a mid-upper arm circumference (MUAC) of less than 24 cm were statistically important predictors of preterm birth in the current pregnancy (14, 17, 19, 30).

On the other hand regarding Fetal related factors, according to a study conducted in Brazil in 2016, multiple gestations increased the risk of prematurity by more than 16 times compared to singleton pregnancies, and another study found that having a congenital defect increased the risk of prematurity by almost three times. Moreover, according to a study conducted in Kenya and other areas, male babies have a higher risk of preterm births than female babies, according to a study conducted in Kenya and other areas (17, 19, 29–32).

Because the outcome variable in this study is binary (preterm birth, yes or no), logistic regression was the model of choice to determine the magnitude of preterm birth and its associated factors. SPSS version 20 software were used for the analysis of the data. The forward type of logistic regression was used to test the independent variables and demonstrate their association with the outcome variable at the p < 0.05 level of significance with 95% confidence interval.

Predictor variables were tested using a binary logistic regression model, and variables with a p-value <0.2 were transferred to run in multivariate logistic regression. When controlling for confounding variables in multivariate analysis, we found that mode of delivery (C/S), type of pregnancy (twin pregnancy), and maternal anemia had a statistically significant association with pre-term birth (p < 0.05). The effect of correlations among independent predictors (multicollinearity) was assessed, and Hosmer–Lemeshow's goodness of fit was checked for fitting these models (0.189).

Mothers who delivered by caesarean section were 2.4 times more likely to have a pre-term birth than those who delivered by Spontaneous Vaginal Delivery (AOR = 2.416; 95%CI: 1.154–5.037). Mothers who had twin pregnancies were more than 3.5 times more likely to give pre-term birth as compared to singleton pregnancies (AOR = 3.524, 95%CI: 1.114–11.150). Anaemic pregnant mothers were more than 3.5 times more likely to have preterm birth as compared to mothers who were not anaemic (AOR = 3.124; 95%CI: 1.417–6.887) (Table 4).

The study was to examine the association between pre-term births and maternal and newborn characteristics in the Debre Berhan Comprehensive Specialized Hospital. The gestational age of the newborn neonate was utilized as a cut-off point to determine the outcome variable, which was less than 37 completed weeks of gestation, but after viability (>28 weeks).

Pre-term birth was determined to be 16.1 percent in this study, with a 95 percent confidence interval of (11.4–19.9), which is higher than the 12.3 percent identified in the Global Action Report for Sub-Saharan African countries (33) and study in Brazil (2016). Dodola, Axum, and Gondar town health institutions showed that (11.5%), ((13%), (13.3%), and (4.4%), respectively (17, 19, 25, 27).

This difference is most likely due to differences in study settings and study areas, or it could be because our study area is at a higher risk than others due to various health-related gaps, such as service quality, or it could be due to differences in health-related medical illnesses and pregnancy-related histories of participants from other areas. On the other hand, studies may differ in settings, such as one study excluding multiple gestations and another excluding those with a history of abortion; however, surgical evacuation of the uterus mechanically stretches the cervix, predisposing such mothers to preterm birth in subsequent pregnancies; thus, study settings may be the reason for the discrepancies observed. However, the results of this study did not differ from those of other studies conducted in Ethiopia, such as those conducted in Addis Ababa public hospitals and the Sehul General Hospital, which reported preterm birth rates of 16.15 percent and 16.9 percent, respectively (26, 34).This similarity in magnitude could be because the two studies mentioned used similar methods to selected study subjects.

The current study's findings were lower than those of a cross-sectional study conducted in Kenya National Hospital and Jemma University Specialized Hospital, which found that preterm delivery was prevalent in 20.2 percent and 25.9 percent, respectively (22, 29) This difference could be attributed to a difference in study time, indicating that the Federal Ministry of Health (FMOH) is now providing better maternal health care than in the past. Another reason for this variation could be differences in the study area. A study conducted in Kenya and Jimma found that the high prevalence of alcohol and substance intake during pregnancy is another contributing factor to increased preterm birth magnitudes in their study area, but this was not the case in our study.

This study found a statistically significant association between cesarean delivery and premature birth. Compared to mothers who delivered via spontaneous vaginal delivery, mothers who delivered via cesarean section had a 2.4 higher risk of premature birth. This conclusion was supported by research conducted in Brazil and Kenya (17, 22). Even if surgical delivery did not have a direct causative relationship with pre-term birth, these groups of mothers were determined to be in the category of premature birth in our study as a result of the medical indication of operation or caesarian delivery conducted before normal labour. Certain maternal or fetal disorders require immediate attention as life-saving interventions. They are also suspected to be a factor in the increased caesarean delivery rates before labor.

In this study, twin pregnancies were associated with pre-term births. Mothers who had twin pregnancies had 3.5 increased odds of pre-term delivery than those mothers who delivered a single baby. This study was consistent with the finding of the studies in Malaysia, Cameron, Kenya, and Axum, respectively (19, 20, 22, 34). Multiple pregnancies are a known predisposing factor for premature birth due to uterine over distension and stretching of the myometrium, encouraging the induction of oxytocin receptors, leading to early onset of uterine contractions and spontaneous preterm birth. Obstetric complications, such as pregnancy-induced hypertension and APH, are common problems in twin pregnancies, which require surgical delivery and increase the risk of preterm birth (35).

Anemic mothers were more than three times more likely to have preterm births than non-anemic mothers. This figure is in line with the findings of Shire and Debre Tabor (21, 32). This might be due to the decreased blood flow to the placenta, which results in placental insufficiency. Physiologically, haemoglobin is transferred from the mother to the fetus through the interface of the placenta; however, when the blood supply decreases, the placenta detaches from the uterine wall, leading to premature labor and delivery. In a normal functioning body, haemoglobin is used as a mine for oxygen transportation to the whole body; therefore, a low Hgb level can cause hypoxia (lack of oxygen or shortage) that increases maternal and fetal stress, which initiates the production of corticotrophin-releasing hormone and leads to the initiation of pre-term labor. Normally, at the time of pregnancy, haemoglobin levels rapidly decrease to balance the blood volume and fit the iron needs of the fetus (36).

This study showed the magnitude of preterm be higher than that of the Global Action Report for Sub-Saharan Africa and some other areas of study. Evidence from this study found that the mode of delivery, multiple gestation, and maternal anemia during recent pregnancy were significantly associated with preterm birth. In summary, the findings of this study showed that preterm delivery is a major public health issue, particularly in the study area.

The Hospital should address iron and folate supplements for all mothers as early as possible before and during pregnancy and strengthen early screening of anemia and high-risk pregnancy, such as multiple gestations. Avian blood bank access is used to manage complications of anemia as early as possible, and it would be better if health professionals watch out and mitigate mothers with problems that might lead to cesarean section. In addition, it would be better if they designed clinical protocols that needed appropriate indications for cesarean section rather than simply trying to remember from different sources of medical science alone.