Risk Factors Associated with Spontaneous Abortion in Dr. Soetomo General Hospital Surabaya: a Case-control Study

The Maternal Mortality Ratio (MMR) in Indonesia is still fairly high. One of the top three causes of maternal death is bleeding. Spontaneous abortion is an early pregnancy problem leading to the occurrence of bleeding and direct maternal death. The causes of spontaneous abortion vary and can be caused by multiple factors. Early identification of risk factors is necessary to reduce mortality and morbidity due to spontaneous abortion and its complications. This study's objective was to identify the risk factors of spontaneous abortion in Dr. Soetomo General Hospital. This study was an observational analytic with a case-control approach. The population was all pregnant women hospitalized at the Obstetrics and Gynaecology Department in Dr. Soetomo General Hospital from January 2017 to December 2018. The samples were 120 in total, included 40 cases and 80 controls taken by consecutive sampling. The data were analyzed using univariate and bivariate analysis with the Chi-square test. The results based on the bivariate analysis showed history of previous abortion (p <0.001), chronic maternal disease (p <0.001), hemoglobin levels (p = 0.020), maternal age (p= 0.026), gravidity (p= 0.036), and infection (p= 0.037) had significant correlation with spontaneous abortion. In conclusion, risk factors associated with spontaneous abortion in Dr. Soetomo General Hospital were history of previous abortion, chronic maternal disease, anemia, advanced maternal age, multigravidity, and infection. Positive pregnancy outcomes are expected to play a role in reducing MMR in Indonesia. Therefore, high-risk pregnant women are suggested to carry out regular Antenatal care recommendations with intensive supervision.


INTRODUCTION
The Bleeding in pregnancy occurs at an early gestational age or later in pregnancy.
Spontaneous abortion is one of the causes of bleeding in early pregnancy. The National Center for Health Statistics, the Centers for Disease Control and Prevention, and WHO define spontaneous abortion as spontaneous pregnancy loss before 20 weeks of gestation or a fetus weighing less than 500 grams (Cunningham et al., 2018).
Around 75% of the incidence of spontaneous abortion happens when gestational age is less than 16 weeks, and 80% of this percentage occurs before gestational age reaches 12 weeks (Konar, 2015).
According to National Health Service, spontaneous abortion occurs in at least 15-20% of pregnancies, meaning that one in 8 pregnancies is at risk of becoming an abortion.
Occupational-environmental factors come from exposure to radiation and chemicals (Sastrawinata et al., 2005). Paternal factors such as sperm abnormalities are also associated with spontaneous abortion (Konar, 2015

Univariate Analysis
The univariate analysis results are listed in

Maternal Age
The statistical analysis showed that the mean maternal age of the case group (31.0 ± 6.397) was higher than the control group (27.58 ± 6.527) and the proportion of high-risk groups (≥  (Johnson et al., 2015).

Number of parity
The statistical analysis result showed that the mean number of parity of the case group (1.08 ±  (Manuaba, 2002).

Gravidity
The statistical analysis showed that the case group's mean gravidity ( Multigravida significantly has a greater risk for spontaneous abortion than primigravida (Fraser et al., 2011). According to Llewellyn-Jones (2002)

History of previous abortion
The results showed that the mean history of abortion in the case group (0.88 ± 1.017) was higher than the average history of abortion in the control group (0.15 ± 0.393), and the proportion of high-risk groups were found more numerous in the cases (57.5%) than controls (13.75%).  (Hacker et al., 2016).
Increased risk of miscarriage in women who are obese may also have relationships with insulin resistance (Johnson et al., 2015).
If the mother is malnourished during pregnancy, the risk and complications of pregnancy include bleeding, lack of weight gain, and infection susceptibility. Low nutritional status can affect fetal growth in the womb leading to abortion, stillbirth, congenital abnormalities, anemia, neonatal mortality, and low birth weight (LBW) (Waryana, 2010).

Infection
The proportion of high-risk groups

Uterine Abnormalities
The proportion of high-risk groups were more numerous in the case group (10.0%) than in control group (0.0%). Chi-square test results showed a significant relationship between uterine abnormalities with spontaneous abortion at Hospital Dr. Soetomo (p = 0.011, p <0.05).
However, the risk of having uterine abnormalities towards the incidence of spontaneous abortion in Dr. Soetomo General Hospital could not be determined because there was a cell count with a value of 0 therefore excluded as a risk factor for spontaneous abortion. The uterine abnormalities found in this study were one case of congenital uterine abnormalities (septum uteri) and 3 cases of acquired uterine abnormality (myoma uteri).

RESEARCH ARTICLE
Leiomyoma or myoma uteri can cause spontaneous abortion. In most cases, the location of myomas is more influential than its size.
Submucosal fibroids have a more significant role than other types (Casanova et al., 2019).
According to Konar (2015), submucosal myoma uteri is associated with distortion or partial obliteration of the uterine cavity.
Some congenital abnormalities such as uterine unicornis, bicornis, and septate uteri may increase the risk of miscarriage in the first trimester, mid-trimester abortion, or premature labor. Abnormalities of uterine development is a consequence of an abnormal formation or fusion of the Mullerian duct (Cunningham et al., 2018).
Congenital malformations of the uterine septum may lead to abortion because of the reduced volume of intra-uterine, reduced placental vascularization, reduced uterine expansion capabilities, and increased uterine irritability / contractility (Konar, 2015).

Maternal Chronic Disease
The proportion of high-risk groups were found more numerous in the case group (57.5%) than in the control group ( (Manuaba, 2002). The type of placental abnormalities found in this study was placenta previa. Placenta previa is the most common type of abnormal placentation. However, placenta previa is generally more associated with antepartum bleeding in late pregnancy than spontaneous abortion. The incidence of bleeding from a placenta previa accounts for 20% of all antepartum hemorrhage cases (Hacker et al., 2016).

Hemoglobin (Hb) Levels
According to the theory described by Cunningham et al. (2018), placental abnormalities such as placenta previa can cause mid-trimester spontaneous abortion. Placental functional impairment, vascular and circulatory disorders can lead to spontaneous abortion (Manuaba, 2002).

CONCLUSION
This study showed that a history of previous abortion, chronic maternal disease, anemia, advanced maternal age, multigravidity, and infection were risk factors associated with the occurrence of spontaneous abortion in Dr.
Positive pregnancy outcomes are expected to play a role in reducing MMR in Indonesia.
Therefore, pregnant women are suggested to carry out regular antenatal care recommendations, and high-risk pregnant women need to receive more intensive supervision.