Preterm birth is defined as a delivery which occurs at less than 37 completed weeks of gestation [1]. Globally, prematurity is the leading cause of death in children under the age of five [2]. More than one in 10 births is born too early in the world and many of those babies die shortly after birth or suffer some type of lifelong physical, neurological or educational disabilities often at great cost to families and society [3]. Preterm births are the leading cause of neonatal deaths accounting for 35% of the world's annual deaths and he survival chances of the preterm babies dramatically depend on where they are born [2]. According to Global Burden of Disease Study, 3.1% of all disability-adjusted life-years was attributed to preterm birth which is similar to the burden of HIV or malaria [4].

Globally, 80% of PTB occur in Sub-Sahara Africa and South Asia with higher morbidity and mortality. Ethiopia is among the top 15countries along with Nigeria, Kenya and Malawi that contribute preterm babies with an estimated preterm birth rate of 14%-23%. The risk of a neonatal death due to complications of PTB is at least 12 times higher for babies born in this area than European baby [2,4]. In Ethiopia, 320,000 babies are born to soon each year, and the report of the Ethiopian Demographic and Health Survey (EDHS) indicated that 30 per 1000 live birth is PTB [2,5].The burden of preterm birth is significantly higher in low-income countries due to higher rates of pre- term birth and limited availability of the required resources in conjunction with low quality service [4]. Preterm birth can also be or provider initiated (induced) [6]. Globally, there are different policies, strategies, and programs that work towards prevention and care of preterm birth and reducing mortality [7]. Yet, still it is the first leading cause of neonatal mortality and the second most common cause of under-five mortality [8]. Ethiopia also developed different policies and programs including expanding Neonatal Intensive Care Unit (NICU), integrated management of neonatal and childhood illness, and quality improvement program to tackle new born death at institution and community levels by controlling major neonatal complications [9]. Besides these efforts, preterm neonatal mortality is still persistently high [9-12]. However, limited studies were done. This study gives current information about magnitude and associated factors of preterm birth to act up accordingly.

Study Area and Period

The study was conducted from April 25 to Sep 22, 2022at selected public hospitals in Addis Ababa, which is the capital city of Ethiopia. There are 12 public hospitals in Addis Ababa [13].

Study Design

Facility based, descriptive cross-sectional study was employed   among mothers who gave birth in Gandhi Zewditu, Rasdesta and Menelik hospital during study period.

Study and Source Population

The source population was mothers who gave birth in randomly selected Hospitals. The study population was randomly selected mothers who gave birth during the study period.

Inclusion and Exclusion Criteria

Women who gave birth during the study period with known LNMP or had ultrasound check up result during their 1st trimester of pregnancy were include in this study, while women who were unable to communicate were excluded.

Sample Determination

Sample size was determined by using single population estimation formula with assumption of 95% confidence interval with 5% margin of error, and considering the 25.9% population proportion of preterm birth taking from the study conducted in Jimma University Specialized Teaching and Referral Hospital, with of 10% nonresponse rate.

N=295 + Non response rate of (0.1*295)

N=295+30=325

N=325

Where

n= the minimum sample size required

P = 0.259

q = (1-p)

d = the desired precision (marginal error) between sample size and population parameter is 5%.

Z α/2 = standard normal score at 95% confidence interval.

Sampling Procedure

Step 1: Among 12 public hospitals four hospitals were selected by simple random sampling technique (Gandhi Hospital, Zewditu Hospital, Rasdesta Hospital and Menelik Hospital).

Step 2: Sample size distribution was allocated for Hospitals according to their population size, average number of deliveries per month at each hospital.

Gandhi Hospital: N=850/2356x325=117

Zewditu Hospital: N=710/2356x325=98

Rasdesta Hospital: N=366/2356x325=51

Menelik Hospital: N=430/2356x325=59

Step 3: Simple random sampling technique was employed and study subjects were selected

Study Variables

Independent Variables:  Age, marital Status, monthly income, ANC visit, history of PTB, pre-mature rupture of membrane (PROM), GHTN, APH, type of pregnancy, gestational age, birth weight, birth interval, parity

Dependent Variable: Preterm birth

Data Collection Procedures and Quality Assurance

Data was collected by face to face interviews using a structured and pretested questionnaire and reviewing patient chart. Gestational age was determined by last normal menstrual period and by early ultrasound which means ultrasound done in the first trimester. Data was collected by four nurses and four midwives, and one public health officer was assigned as supervisor. Both data collectors and supervisor were trained on how to collect the data.

Data Management and Data Analysis

The data was entered, cleaned, and edited using EpiData version 3.1 and was exported to SPSS version 25.0 software packages for analysis. Both bivariate and multiple logistic regression analysis was done. Variables with ???? value < 0.25 in bivariate analysis was entered in to multivariate analysis and variables with ???? value < 0.05, 95% CI in multivariate were considered statistically significant.

Operational Definitions

Anemia: is the condition that can occur during pregnancy when blood hemoglobin (Hb) concentration of less than 11g/dl [12].

Preterm Birth: Defined by the World Health Organization (WHO) as a birth occurring before 37 weeks of gestation.

Preterm Birth: a delivery which occurs at less than 37 completed weeks of Birth.

The Birth Interval: the number of months since the previous birth. It was considered as either being short or optimal if the birth interval was <24 months and ≥24 months, respectively.

APH (Antepartum Hemorrhage): Is defined as bleeding from the genital tract occurring from 24+0 weeks of pregnancy and prior to the birth of the baby.

Pre-Mature Rupture of Membrane (PROM): Premature / pre-labor rupture of fetal membranes is rupture of membranes (ROM) before the onset of labor.

Ethical Consideration

A written permission letter was obtained from research and community service of Yanet College, and ethical clearance was obtained from Addis Ababa health Bureau. Permission was obtained from Gandhi, Zewditu, Rasdesta and Menelik hospital administrator to conduct the study, and lastly, consent was obtained from the respondents and confidentiality of the data was ensured by omitting the names of the respondents.

Socio-Demographic and Behavioral Characteristics

From the total of 325 participant most were in the range of 25-35 ages. Majority of the women, who gave birth 310 of 325 (95.4%) were urban dwellers, also most participants 309 (95.1%) were married. From overall proportion 21 (6.5%) had no formal education. In addition to these, all participants had not chewed chat, smoke cigarettes and drink alcohol in the last nine months. From occupational status of mothers few 34 (10.5%) were merchants and only few families had > 10,000-birr monthly income. Concerning family size only 59 (18.2%) mothers had greater than 5 families in the house (Table 1).

Table 1: Socio-Demographic Characteristics of respondents.

Mother and Fetus Related Characteristics

From result 306 (94.2%) of respondents had ANC follow up, majority of them 281 (86.5%) had greater than or equal to four ANC visits. Concerning parity, 184 (56.6%) were primipara and 10 (3.1%) of them were greater or equal to Para 5 and birth interval of greater or equal to 24 months were 104 (32%). Among respondents 46 (14.15%) had gestational hypertension and 50 (15.38%) had anemia. From previous obstetric history, 42 (12.9%) of participants had previous history of preterm birth and 40 (12.3%) had premature rupture of membrane in the current birth. In this study about 23 (7.08%) were multiple pregnancy. According to birth weight the majority 243 (74.8%) were at the range of birth weight (2,500g-4,000g) and 11 (3.4%) were above 4000g.

Table 2: Mother and fetus related Characteristic.

Magnitude of Preterm Birth

The magnitude of preterm birth in this study was 13.5% [95% CI (9.5%, 17.5 %)].

Factors Associated With Preterm Birth

In this study multivariable logistic regression shows that: Gestational Hypertension (AOR=2.7,95% CI:1.235,6.144) ,PROM (AOR=3.0,95% CI :1.3291,6.868), multiple pregnancy (AOR=2.7 95% CI :1.028,7.356)  and APH (AOR=3.3 95% CI: 1.166,9.625) found to be significantly associated with preterm birth (Table 3).

Table 3: Factors associated with preterm births among women who gave birth at public hospitals in Addis Ababa Ethiopia 2022.

In this study, the prevalence of preterm birth was observed to be 13.5% [95% CI (9.5%, 17.5 %)].This finding is consistent with the study conducted in United States, Central and Eastern Europe, Nigeria, Debretabor (Ethiopia), French Caribbean population ,Malawi and Addis Ababa which were 10.23%,10.2%,  11.8%,12.8% 15.8%,16.3% and 16.15%  respectively . This may be due to similar study design [14-17]. The magnitude in this study was lower than study conducted in Sub-Saharan Africa and Kenya, which were 60% and 18.3% respectively [4,18], and in contrast studies done in Algeria (9.26%) and England (7.8%) have  lower prevalence of preterm birth compared to this study. This might be due to better preventive intervention in health-related program in Algeria and England [15].

In this study mothers who had gestational hypertension were 2.7 times more likely to deliver preterm birth in comparison to mothers with normotensive mothers. This study is consistent with study done in public hospitals of western Ethiopia and Tigray regional state [16,19]. This may be caused by hypertension decreasing utero-placental blood flow, which in turn causes intrauterine growth restriction and ultimately preterm birth. Mothers who had experienced PROM were 3 times more likely to deliver preterm birth than their counterparts. This result is consistent with study done in Iran [20]. Mothers with APH were 3.3 times more likely to have preterm delivery than counterparts. This might be because APH puts both the fetus and the mother at danger during pregnancy [17,19,21], and also multiple pregnancies were 2.7 more likely to have preterm births than counter parts. The outcome is consistent with previously published studies [22].

Preterm birth is still public concern in the study area. The common risk factors for preterm birth at public hospitals in Addis Ababa were Pregnancy induced hypertension, premature rupture of membrane (PROM) multiple pregnancy and Antepartum Hemorrhage (APH) which are major public health problems. Early detection and treatment of diseases or disorders among pregnant women as well as the improving health care quality delivered to pregnant woman may reduce risk factors for preterm delivery. Obstetric Care providers are highly recommended to early identify and refer for specialized obstetrical evaluation and management of those who have high risk of preterm birth mothers in early pregnancy. In Ethiopia, Preterm birth is still a public health problem it is better to expand neonatal intensive care unit that equipped with the necessary materials and trained staff to management and prevention of complication.

Our study is limited to Hospital-based quantitative study. It would be better if qualitative approach study was triangulated to investigate further factors on preterm birth. Recall biases in remembering the exact day of last normal menstrual period.

Strength

Since there were no enough studies done in an area according to the magnitude of the problem, this study contributes by alerting researchers for further study.

Abbreviations

ANC: Ante Natal Care, EDHS: Ethiopian Demographic Health Survey, HIV: Human Immune deficiency Virus,   LBW: Low Birth Weight, LNMP: Last Normal Menstrual Period, NICU: Neonatal Intensive Care Unit, PROM: Premature Rupture of Membrane, PTB: Pre Term Birth, SPSS: Statistical Package for the Social Science, WHO: World Health Organization.

Data Availability

The data set used and analyzed for the current study is available from the corresponding author on a reasonable request.

Supplementary Materials

This study is reported according to the STROCSS 2021 guide line for reporting cross-sectional study [23].

Conflict of Interest

There is no conflict of interest

Funding Statement

This research did not receive any specific grant from funding agencies

We would like to forward our gratitude to Yanet College, for giving ethical clearance to conduct the research. We also submit our sincere gratitude to data collectors for their undeniable efforts. We thank our respondents for their respect and proper responses. Likewise we would like to send our special thanks to ministry of health and administrator of Gandhi, Zewditu, Menenilik and Rasdesta hospital that allows us to do this research and provide necessary information.

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