Disparities in adverse pregnancy outcomes between advanced maternal age and younger age in Ethiopia: Institution based comparative cross-sectional study

Women older than 35 years are known to beat “advanced maternal age" and considered to be at risk of adverse pregnancy outcome. Data, on adverse birth outcomes and the risk factors are still scarce in developing countries including Ethiopia. The aim of this study was to examine the obstetrical outcomes among primiparous and multiparous women of advanced age (35 and above) when compared to the younger  age group (20 to 34) and identify its predictors among women delivering at public health facilities of Shashemene Town, Ethiopia. Institution based comparative cross sectional study were conducted from March to April, 2016. A consecutive sampling technique was employed to select 306 study participants. Data were collected using pretested structured questionnaires through face to face interview and checklist. Data were entered into Epi-data version 3.1 and analyzed using SPSS version 20.0. Logistic regression analyses were used to identify associated factors. A total of 306 mothers were involved in this study with response rate of 100%. Advanced maternal age, antenatal follow up, mode of current delivery and previous caesarian section were factors associated with adverse pregnancy outcome. 
 
 Key words: Adverse pregnancy outcomes, advanced maternal age, participants.


INTRODUCTION
Globally, women and children are among the most vulnerable in terms of unfavorable influences in the environment including insufficient nutrition, inadequate health care and poor education.In addition, pregnancy brings those factors as high risk for women.Worldwide, it is estimated that more than 50 million women suffer from poor reproductive health and serious pregnancy related complications (Tesfay et al., 2015).
Mothers age 35 and above at estimated date of delivery is known to be old maternal age (Yogev et al., 2010).Older age is risk factor for decreasing fertility and increasing miscarriage.For women who succeed in *Corresponding author.E-mail: mekediris@gmail.com.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License conception at higher age, the risk of complication during pregnancy and delivery is high (Almhfooth et al., 2013).Older pregnant mothers have an increased risk of pregnancy, labour complications and adverse fetal outcome.Medical complications like hypertensive disorders, gestational diabetes and preterm birth and labour related complications like induction of labour, prolonged labour and hemorrhage are the most common ones.This aged group mothers mostly delivered with caesarean section and their children will have a higher risk of congenital anomalies and will face fetal and neonatal mortality (Tromp et al., 2010).Even if the issue is essential and its effect is bad to the mother and fetus, studies on this area lack adequate data.Therefore this study aimed to compare pregnancy outcomes between advanced maternal age and younger age and identify predicting factors among women delivering at public health facilities of Shashemene Town.

Study setting and study period
Shashemene town is situated in West Arsi Zone in Oromia Regional State, Ethiopia ("CSA-Ethiopia", 2012).The city lies on the trans-African highway 4 of Cairo-Cape town, about 150 miles (240 km) from Addis Ababa.Based on the 2007 population Census, the population size of Shashemene were 102,062 of which 51,477(50.4%)are males and 50,585 (49.6%) are females.According to the Central Statistical Agency of 2005, females 35.2% (16,288.5)were in reproductive age group (15 to 49), the total fertility rate was 4.2.The population expected for 2013 using the census data in 2007, was 129,084, of which 65,091 were men and 63,993 were women.

Study design and population
A comparative cross sectional study was conducted on pregnancy outcomes among women aged 20 to 34 years and 35 + delivering at public health facilities in Shashemene town.All pregnant mothers who gave birth at public health facilities of Shashemene town, Ethiopia, from March to April, 2016 were taken as source population and selected mothers who gave birth during the study period at public health facilities of Shashemene town, Ethiopia taken as study population.All mothers 20 years and above who gave birth at public health facilities of Shashemene town, Ethiopia during data collection period were included and women who were seriously ill and unable to respond were not included in the study.

Ethical consideration
Ethical clearance was obtained from the Institutional Review Board (IRB) of Jimma University College of Health Sciences to shashemene town health facility authorities.Permission letters were obtained from Shashemene Referral Hospital and Melkaoda Hospital Administration, after the objectives of the study were explained, consent was obtained from head of maternal and child health unit.Written and verbal consent were taken from selected participant to validate willingness to participate in the study before the interview.Privacy and confidentiality were ensured by using coding.

Sampling technique
A comparative cross sectional study was conducted among women aged 20 to 34 years and 35 + delivering at public health facilities in the town.

Data collection tools
Data were collected using pretested and structured questionnaire and through chart review.Questionnaire contained socio demographic, obstetrics, medical history and other characteristics.

Data analysis and quality control
Collected data were entered into Epi data version 3.1 and exported to SPSS version 20.0 for analysis.After cleaning data for inconsistencies and missing value in SPSS, binary logistic regressions with p value < 0.25 were transferred to multivariable logistic regression.Variables with p value < 0.05 were considered significant variable.Training for data collectors, pretest and supervision were undertaken to control data quality.

Socio demographic characteristics of the respondent
Three hundred and six study participants participated with a response rate of 100%.The mean age of women (20 to 34) was 24.39 (SD ± 3.865).Regarding residence in the age group 20 to 34, 88 (50.3%) were living in urban.Married women between age 20 to 34 was 151.Those mothers who can read and write were 49(32.02)and 31(20.2) in both age group, respectively.Oromo was the dominant ethnicity is the study area with 110 (71.89%) and 102 (66.69%).Majority of participants in both age group were housewives in their occupation 116 (48.7%), 112(79.7%)and their Income ranged from 1801 to 3000 48.3 (31.37%) (Table 1).

Medical related complications of the respondents
Advanced reproductive age group mothers who do not  3).

Frequency of maternal adverse pregnancy outcomes of the respondent
While comparing the prevalence of adverse maternal pregnancy outcomes among women aged 20 to 34 and 35 + , the risks were high among advanced maternal age (Table 4).

Frequency of fetal adverse pregnancy outcomes of the respondent
Adverse pregnancy outcome at normal reproductive age group was 45(29.41%)and in advanced age group it was 62(40.5%).Adverse fetal outcomes were more at advanced maternal age in comparison with normal reproductive age group except still birth which was the same frequency among the two age group (Table 5).In binary multiple logistic regression age, education, ethnicity, occupation, outcome of last delivery, previous caesarian section and antenatal follow up showed association with p value < 0.2, these variables transferred to multivariate logistic regression then age, antenatal follow up, previous caesarian section and mode of current labour showed significant association with p value < 0.05 (Table 6).

DISCUSSION
The study revealed that the prevalence of adverse pregnancy outcomes was 45(29.41%)and 62(40.5%)among mothers aged 20 to 34 and 35 + , respectively.This study showed that adverse pregnancy outcomes were highly prevalent in advanced maternal age when compared to younger age group.The study done in Norway from 2004 to 2007 ruled out that the prevalence of adverse pregnancy outcomes among advanced maternal age was 33.4% (Laopaiboon et al., 2014).
Another study conducted in Taiwan found that the prevalence is from 11.4 to 19.1% (Jahromi and Husseini, 2008).A large, population-based cohort study in the UK showed an 18.2% prevalence of adverse pregnancy outcome among maternal ages of 35 years or older (Kenny et al., 2013).The prevalence of hypertensive disorder of pregnancy in advanced maternal age was higher when compared to their younger counterparts.This study was similar to the study conducted in Nigeria (Liou et al., 2010).This might The prevalence of postpartum hemorrhage in advanced maternal age was higher when compared to their younger counter parts.This study was supported by the study done in Israel (Tesfay et al., 2015).Also according to Laopaiboon et al. (2014), the prevalence of caesarian delivery was 6 times higher among advanced maternal age when compared to younger mother.Study done in Nigeria supports this result; advanced age has higher incidence of cesarean delivery than their counterparts (Bako et al., 2013).These two findings can be based on the reason that advanced age women are more likely to be grand multi-para and this may lead them to face postpartum hemorrhage due to uterine atony.Obstructed labour, prolonged labour, mal presentation and related fetal complications which is more common in advanced maternal age may lead them to caesarean section than their counter part.
Adverse fetal outcome like low birth weight, preterm birth, Apgar score 5 min < 7, congenital anomaly, admission to neonatal intensive care unit (NICU) and fetal death are highly related with advanced age group.This result is similar with a study conducted in Turkey which ruled out that advanced maternal age were significantly associated with fetal complication and Apgar score 5 min < 7 (Lamminpää, 2015).Similarly, study conducted in Flemish found that advanced maternal age were associated with very preterm and low birth weight (Delbaere et al., 2007).
Advanced maternal age (35 + ) was 2 times risky of wide range of adverse pregnancy out come when compared to mothers in normal reproductive age group (20 to 34).The result is in line with a case control study conducted in Iran, which revealed that advanced maternal age of 40 and above were more complicated by maternal and neonatal complication (Khalil et al., 2013).A retrospective study done in Spain supports this result (Jahromi and Husseini, 2008).In this study antenatal care follow up was significantly associated with adverse pregnancy outcome.Studies done in Gondar University Hospital, Northwest Ethiopia rule out that lack of ANC follow up were associated with adverse pregnancy outcome like still birth (Adane et al., 2014).
A prospective study done at University Hospital UZ Brussels proved that lack of antenatal follow up was associated with adverse pregnancy outcome like preterm (Beeckman et al., 2012).Mode of current labour is significantly associated with adverse pregnancy outcome.Most mothers who came to this hospital were referred from health center with complication that leads to caesarian section.Mothers who deliver by caesarian section were more risky to develop adverse pregnancy outcome than those who delivered by spontaneous vaginal delivery.Caesarian section is a major operation which can be associated with significant maternal and fetal, morbidity and mortality.This can be due to the fact that bleeding in caesarian section is higher than vaginal delivery, this can lead mother to risk of death (Arulkumaran, 2016).

Conclusion
In this study, adverse pregnancy outcome is high in advanced maternal age.Postpartum hemorrhage and Hypertensive disorders are mostly observed adverse outcomes in advanced maternal age.Age, antenatal

Table 1 .
Sociodemographic characteristics of participants in women attending public health facilities of Shashemene Town, Ethiopia, 2016 (N =153).

Table 2 .
Obstetric characteristics of participants in women attending public health facilities of Shashemene Town, Ethiopia, 2016 (N= 153).

Table 3 .
Medical related complications of women attending public health facilities of Shashemene Town, Ethiopia, 2016.N =153.

Age Normal reproductive age group (20-34) Advanced reproductive age group (35-49
be due to the reason that old age is one of a risk factor for pregnancy induced hypertensive disorder.

Table 4 .
Frequency of maternal adverse pregnancy outcomes of women attending public health facilities of Shashemene Town, Ethiopia, 2016.

Table 5 .
Frequency of fetal adverse pregnancy outcomes among women at public health facilities of Shashemene Town, Ethiopia 2016.

Table 6 .
Multivariable logistic regression Analysis of Adverse pregnancy outcome among women age 20-34 and 35 + delivering at public health facilities of Shashemene Town, Ethiopia 2016.