Determinants of Adverse Birth Outcomes in Ambon, Indonesia: A Case-Control Study

Background: Globally, adverse birth outcomes were still high, especially in low and middle-income countries like Indonesia. Stillbirth, preterm birth (PTB), low birth weight (LBW)


INTRODUCTION
Birth outcomes are the results of the fertilization process, which are assessed from the age of viability (28 weeks) to the first week of the newborn.Birth outcomes include normal live birth, preterm birth (PTB), intrauterine fetal death (IUFD), stillbirth, low birth weight (LBW), and neonatal death.Adverse birth outcomes is a term used to describe health problems in mothers and newborns during pregnancy, childbirth, and postpartum.Stillbirth, premature delivery, low birth weight, and birth defects are some of the adverse birth outcomes. 1obally, an estimated 13.4 million babies were born preterm in 2020, and 1.9 million lategestation stillbirths (at 28 or more weeks) in 2021.Meanwhile, preterm birth, childbirth-related complications (birth asphyxia or lack of breathing at birth), infections, and birth defects caused most neonatal deaths in 2019. 2 Based on the 2021 Indonesian Health Profile data, it was found that infant deaths in 2021 were 27,566 and experienced a decrease compared to 2020, 28,158 in Indonesia.About 73.1% were stillbirths to deaths in the neonatal period, LBW 34.5%, 27.8% neonatal asphyxia, and 12.8% congenital abnormalities. 3 Expected adverse pregnancy consequences comprise placental abnormalities, neonatal low birth weight, preterm birth, macrosomia, abortions, and stillbirths.These variation outcomes significantly impact pregnant women's and neonates' physiological and psychological wellbeing. 4,5Also, those adverse pregnancy effects can cause long-term physical and neurological disorders in surviving babies, even death. 69][10][11][12][13][14] Also, a history of antenatal care (ANC) is a risk factor for adverse pregnancy outcomes.6] Routine antenatal care during pregnancy can detect adverse birth outcomes. 14In addition, a study in Indonesia presented that access to prenatal care can predictably reduce adverse outcomes both for the mother and the infant. 17search on the determinants of adverse birth outcomes in Indonesia is limited.Likewise, in Ambon, research on adverse birth outcomes has never been conducted, even though the incidence of adverse birth is quite high.In 2021, there were 22 stillbirths, 29 neonatal deaths, and 215 LBW.
Data was collected from the birth outcomes based on the mother and child cohort at the Puskesmas dan Posyandu.All birth outcomes were considered the case and control groups.The inclusion criteria included pregnant women who lived at home with their husbands in Ambon City.On the other hand, unwillingness to participate in the study was considered an exclusion criterion.
The sample size was calculated by taking power at 80%, a confidence level at 95%, and the ratio of case to control was 1:2.The total sample size was 165, with 55 cases and 110 controls.
In this study, adverse birth outcomes were defined as the presence of either of parameters such as preterm birth, low birth weight, firstminute birth asphyxia, or stillbirth.Data analysis was done using SPSS software version 21.Bivariate associations between independent variables and dependent variables were tested through the Chi-square test.The association was analyzed by calculating crude odds ratios (OR) at a 95% confidence interval through binary logistic regression.Multivariate logistic regression was examined for the relationship between independent and dependent variables to address the confounding effect.The Ethics Committee of the Hassanudin University of Health Faculty approved the study (Ethic code: 5038/UN4.14.1/TP.01.02/2023).

RESULTS
The most common adverse birth outcome was PTB (32.73%) (Table 1).Most of the respondents who participated in the study were aged 21-35 years in both the case and control groups (63.64% vs. 82.73%).There was a difference in maternal age between case and control groups (p=0.006;95% CI: 1.22-6.11).The highest number of parities was one and ≥5 in the case and control groups (81.82% vs. 56.36%).This study showed a difference in parity between case and control groups (p=0.001;95% CI: 1.52-8.51).Respondent characteristics were more dominant as passive smokers in the case and control groups (85.45% vs. 63.64%).The study showed the difference between mother passive smokers in case and control groups (p=0.004;95% CI: 1.37-8.99).(Table 2).
This study showed that most ANC examinations were carried out not according to standards in both groups (72.73% vs. 53.64%).Cases group has more risk of adverse birth outcomes than the control group (p=0.02;95% CI: 1.08-5.01).Meanwhile, the case and control groups were dominated by ANC counseling without their husband (83.64% vs. 60%).There was a difference in the case and control groups (p=0.002;95% CI: 1.44-8.67)(Table 3).
Multivariable analysis was carried out to determine the effect of the independent variable on the dependent variable.Simultaneously controlled for variables that had a p-value <0.25 in the bivariable test analysis, namely age, parity, and passive smoking.The results of the analysis showed the influence of the variables ANC counseling, maternal age, parity, and passive smokers on birth outcomes was 15% (Table 4).Meanwhile, the influence of the variables ANC examination, maternal age, parity, and passive smokers on birth outcomes was 14% (Table 5).

DISCUSSION
This study aims to analyze the determinants of adverse birth outcomes in Ambon.The results of the study show the impact of maternal age, parity, passive smokers, ANC examination and ANC counseling on  The maternal age at risk has a 2.74 times chance of an adverse birth outcome.A meta-analysis study showed that maternal age >35 years was associated with a 65% increased risk of stillbirth, with a higher relative risk at age 40 years. 18Similar research has also shown a relationship between older pregnant women and increased rates of low birth weight (LBW) and preterm births. 19 addition, pregnancy at a young age is also associated with negative impacts on the child's health such as preterm birth, low birth weight, malnutrition, and poor development. 20Thus, pregnancy at a young or late age is associated with an increased risk of adverse birth outcomes. 12rity is also a factor that impacts birth outcomes, with a 3.48 times chance of adverse birth outcomes compared to women without risk.
A meta-analysis study showed that women with parity ≥3 and aged over 35 years had an increased risk of prematurity and neonatal death compared with women with parity 1-2 and aged between 18 and 35 years old. 21Multiparity causes changes in the elasticity of the uterine wall and the emergence of uterine scar tissue so mothers tend to experience complications during pregnancy and childbirth. 22men passive smokers are 3.36 times more likely to experience adverse birth outcomes than women who do not smoke passively.These results were in line with previous studies which have explained that pregnant women who are exposed to cigarette smoke have an increased risk of   (Levy et al., 2021).A study in Ambon also showed that passive smoking in pregnant women was a risk of stillbirth. 25is study found that pregnant women who have an ANC examination not according to standards have a 2.3 times chance of adverse birth outcomes compared to pregnant women who have an ANC according to the standards.According to our study, ANC counselling without being accompanied husband is 3.41 times more likely to adverse birth outcomes compared to ANC counselling accompanied by a husband.][30][31] Unfortunately, male partner involvement in antenatal care is low globally and more so in low and middle-income countries. 32,33There are many barriers to men involved in the ANC including economic, cultural, and health facilities. 32On the other hand, previous ANC experience also impacts men's involvement in ANC. 34sed on our research, the prevalence of PTB is higher than other adverse birth outcomes.This was possibly due to inaccuracy in reporting the LMP. 35[38][39][40][41][42] A limitation of this study is that more determinants associated with adverse birth outcomes were not included.However, this research has the advantage of analyzing ANC counseling factors accompanied by husbands that are not explored by other studies.In addition, our research was the first to be conducted in Ambon to examine adverse birth outcomes.
Additionally, the association of other risk factors like socio-economic status, culture, history of previous ANC as well as modifiable risk factors should be accounted for in future research.

CONCLUSION
The adverse birth outcomes were quite high in Ambon and the most common was PTB.Maternal characteristics that impact adverse birth outcomes are mothers, parity, and mothers who are passive smokers.In addition, ANC examinations are not according to standard, and ANC counseling without being accompanied by the husband contributes to adverse birth outcomes.

Table 5 : The relationship between ANC examination and birth outcomes involves the characteristic pregnant women: logistic regression analysis.
adverse birth outcomes including placental malperfusion, fetal growth restriction, premature events, asphyxia, and LBW(Ballbè et al., 2023;  Levy et al., 2021; Liu et al., 2023).Substances contained in cigarette smoke can disrupt placental development by altering the balance between the proliferation and differentiation of cytotrophoblasts by reducing blood flow, thereby creating a pathological hypoxic environment