Identification of eligible studies
From the outset, we searched a total of 19635 records by the electronic search through a search engine of PubMed, MEDLINE Google scholar, EMBASE, worldwide web of science and Cochrane Library. , 62 of them were removed due to duplication from the inclusion. After the remaining19635 retrievals, 8120 records were excluded due to publication year, they were published before 2012.then from the remaining 11515records 11471 were excluded since they were not related to study in general. Then in the last 44 full text studies were considered and tested for the eligibility based on the pre-set eligibility criteria. In the last 09 studies were considered to be eligible and included in this meta-analysis and systematic review analysis, in detail see study selection process (see figure 1). From a total of 44 full text studies accessed, we removed 31 of them because they were based on single exposure to study outcome articles, characteristics of original studies.
Description of original included studies
Table 01 summarizes the descriptive characteristics of the 13 studies included in this meta-analysis and systematic review. The studies were conducted in health facility and community setups. Four of them were conducted in community set up [20-23] and the remaining were in facility set up [1-3, 24-28]. When we see by design two of them cross sectional ,one of them prospective and one retrospective cohort ,four of them un matched case control ,two of them nested case control and three case control study design and conducted in different parts of Ethiopia with a sample size ranging from 219 in north shewa zone , Oromia region [21] to 3786 in dabat demography and health surveillance center , central Gondar, Amhara region [20].The included studies have been conducted in the four regions of Ethiopia: one included study was carried out in Addis Ababa: [3], three studies were conducted in Amhara region [20, 22, 28],four were from oromia region [21, 23, 27, 29] ,one from Tigre region[2] and four from Southern Nations, Nationalities and peoples’ region (SNNPR) SNNP [1, 24-26]
The original studies included in this study and reporting response rate had a response rate of 100% showing that all the studies had good response rate. The quality of the articles were done and all of them had low risk. Among included studies two unpublished and eleven published studies were included. The studies included in the meta-analysis were identified by exhaustive search from reputable journals
Table 1: Characteristics of original articles included in studies
Author
|
Publication year
|
Setting
|
Region
|
Study area
|
Design
|
Sample
|
Response rate
|
Quality
|
Goba etal
|
2018
|
Health facility
|
Tigray
|
Southern zone
|
Case –control
|
378
|
100%
|
Low risk
|
Tesfaye etal
|
2019
|
Health facility
|
SNNP
|
Arbaminch
|
Case-control
|
821
|
100%
|
Low risk
|
Yirgu etal
|
2016
|
Community
|
Amhara
|
West Gojam zone
|
Nested case control
|
306
|
100%
|
Low risk
|
Roro etal
|
2018
|
Community
|
Oromia
|
North Showa Zone,
|
Nested case control
|
219
|
100%
|
Low risk
|
Getiye etal
|
2017
|
Health facility
|
Addis Ababa
|
Addis Ababa
|
Unmatched case- control
|
1113
|
100%
|
Low risk
|
Mihiretu etal
|
2017
|
Health facility
|
SNNP
|
Wolaita sodo
|
Crossectional
|
300
|
100%
|
Low risk
|
Bayou etal
|
2012
|
Health facility
|
SNNP
|
Hawassa
|
Unmatched case –control
|
1356
|
100%
|
Low risk
|
Andargie etal
|
2013
|
Community
|
Amhara
|
Dabat
|
Prospective cohort
|
1752
|
100%
|
Low risk
|
Aragaw etal
|
2016
|
Health facility
|
Oromia
|
Jimma
|
Crossectional
|
3786
|
100%
|
Low risk
|
Tebeje etal
|
Not published but study year 2018
|
Health facility
|
SNNPR
|
Tercha
|
Unmatched case-control
|
366
|
100%
|
Low risk
|
Neme etal
|
2020
|
Health facility
|
Oromia
|
Jimma
|
Retrospective
|
186
|
100%
|
Low risk
|
Mihretie etal
|
Not published and Study year 2020
|
Health facility
|
Amhara
|
Bahirdar
|
Unmatched case control
|
459
|
100%
|
Low risk
|
Debelew etal
|
2020
|
Community
|
Oromia
|
Jimma
|
case control
|
480
|
100%
|
Low risk
|
Meta-analysis
Associated factors of perinatal mortality
We reviewed and meta-analyzed the factors associated in bivariate logistic regression in the included articles and reported in multivariate logistic regression with dependent variable of perinatal mortality in original articles .By using 13 relevant studies included in this study the following variables were entered in meta-analysis: History of previous abortion ,presence of obstetric complication ,history of previous perinatal death, partograph use ,prenatal visit, birth weight ,child birth interval ,level of hemoglobin, TT vaccination , education status of mother, gestational age, fetal presentation ,mode of delivery , number of deliveries and sex of the new born were meta analyzed. Among those History of previous abortion ,presence of obstetric complication ,history of previous perinatal death, partograph use ,prenatal visit, birth weight ,child birth interval ,level of hemoglobin, TT vaccination of mother, education status of mother ,fetal presentation and gestational age were significantly associated variables with perinatal mortality .
The pooled effect size of three studies showed that Mothers without history of previous abortion had 50% times less risk of losing their newborn in perinatal period as compared to those who had a history of abortion (OR= 0.50(95%CI: 0.29, 0.85), in detail see (figure 2,e)
The effect of seven studies about the mothers with no history of previous perinatal death had 79% times less risk of losing their newborn as compared to mothers with history of perinatal death (OR=0.21,95% CI:0.14 -0.32), in detail see (figure 2, k)
The pooled effects of six studies about fetal presentation revealed that fetus with vertex presentation had 64% less risk of perinatal death as compared to fetus with non-vertex (OR=0.36(0.21,0.60),in detail see (figure 2,c)
The pooled effect of the seven studies about mothers without obstetric complication had 85% times less risk of perinatal deaths as compared to mothers with obstetric complications (OR=0.15,95%CI: 0.06, 0.37), in detail see( figure 2,i) .
The pooled effects of five studies revealed that women who delivered without the support of a partograph had an 4.68 times higher odds of experiencing perinatal mortality as compared with those delivering with support of a partograph(OR=4.68,95%, 2.75,7.94),in detail see (figure 2, j) . The pooled effect of the eight studies showed that mothers who had no ante partum follow up were 2.57 times higher odds of experiencing perinatal loss as compared to those who had follow-up (OR=0.46, 95%CI, 2.08, 3.17), see (figure 2, f).
The pooled effects of the six studies revealed that Mothers who gave birth to birth weight greater than 2500 gram were 85% times less likely to had perinatal death as compared to those who gave birth to less than this birth weight baby (OR= 0.15, 95% CI (0.07, 0.32),in detail see (figure 2,a).
The pooled results of the five studies showed that the odds of perinatal mortality were 2.57 times higher among mothers whose previous delivery was within two years of current delivery as compared to mothers whose child delivery was more than or equal to two years (OR 2.57; 95% CI (1.56,4.22),in detail see (figure 2 ,b).
The pooled effects of three studies revealed that perinatal mortality were 52% times less likely among women’s with hemoglobin level of greater than or equal to 11g/dl mothers as compared to hemoglobin level less than 11 g/dl (OR =0.48; 95%CI (0.36,0.65)) ,see ( figure 2, g).
The effects of four studies showed that not immunized mothers for TT vaccine during pregnancy had 2.23 times risk of losing their baby as compared to immunized mothers (OR =2.23;95%CI(1.51,3.30), see (figure 2,i).
The pooled effects of five studies showed that mothers with illiterate education status had 1.99 times more likely to lose newborns in perinatal period as compared to mothers whose educational status was primary and above (OR=1.99;95%CI(1.52,2.61),in detail see (figure 2,h).
The pooled effects of ten studies revealed that the odds of perinatal mortality were 6.61 times higher among preterm deliveries than term deliveries (OR= 6.61; 95%CI (4.58, 9.55), in detail see (figure 2, d)