Epidemiology analysis of the incidence of severe maternal outcomes between level 2 and 3 hospitals in China’s Hunan province from 2012 to 2018

Background: This facility-based study analyzed the epidemiology and incidence of maternal near-miss (MNM) and mortality by hospital level as part of Hunan efforts to raise hospital care for women. Methods: We used data for MNM and mortality cases for 2012–2018 from 17 hospitals (12 level 2 facilities, five level 3 facilities) that receive referrals for obstetric complications in Hunan province. Data were drawn from China’s National Maternal Near Miss Surveillance System, and collected using the World Health Organization near-miss tool. We calculated the ratio of severe maternal outcomes (SMO) (i.e., MNM and maternal death [MD] cases), mortality index (MI), and MNM to mortality ratio (MNM:MD), and epidemiological factors, organ dysfunction, and maternal complications stratified by hospital level. Chi-square tests to examine differences between groups and total ratios and 95% CI were calculated. Results: There were 518 SMO cases (489 MNM and 29 MD) among 279407 live births (LBs) and 1299 SMO cases(1262 MNM and 37 MD) among 232386 LBs in level 2 and 3 facilities. The total MNM ratio in level 2 and 3 hospitals was 1.75 (95%CI: 1.60–1.91) and 5.43 (95%CI: 5.14–5.74) per 1000 LBs, respectively. There were differences in SMO cases between level 2 and 3 hospitals in maternal age, education, parity, antenatal visits, and history of cesarean sections. In MNM cases, coagulation dysfunction was the main organ dysfunction (level 2 hospitals: 59.10%; level 3 hospitals: 79.32%), and the main maternal complications were obstetric hemorrhage (level 2 hospitals: 71.98%) and hepatopathy (level 3 hospitals: 69.49%). For MD cases, the main maternal complications were neurologic dysfunction (level 2 hospitals: 41.38%) and coagulation dysfunction (level 3 hospitals: 42.55%). Anemia was the main maternal complication for SMO cases in both level 2 (69.69%) and 3 (68.59%) hospitals. and MD in level 3 compared with level 2 The obstetric emergency capacity of level 3 hospitals is higher than that of level 2 hospitals. suggest future government policies should consider upgrading the obstetric emergency treatment capacity in level 2 hospitals to re-distinguish the social functions of different


Background
The maternal mortality ratio (MMR) represents the number of maternal deaths per 100,000 live births (LBs), and is a core indicator of a country's health and social development. Many countries have reported decreasing MMRs in the context of economic development and improved population health.
The Global Burden of Disease study showed that over the last decade, the MMR fell by about 30% worldwide, from 288 in 2000 to 196 in 2015 [1]. Maternal mortality also declined by 8.9% per year between 1997 and 2014 in China, which has achieved Millennium Development Goal 5 (i.e., a 75% reduction the MMR between 1990 and 2015) [2]. The MMR in China's Hunan province declined by 45.24% between 2009 and 2014 [3]. Today, maternal death (MD) has become an extremely low probability event in developed countries and parts of developing countries, although severe maternal morbidity or maternal near-miss (MNM) cases remain major public health challenges for healthcare systems globally [4]. MNM is defined by the World Health Organization (WHO) as "a women who nearly died but survived a complication that occurred during pregnancy, childbirth or within 42 days of termination of pregnancy" [5][6][7]. The concept of MNM as developed by the WHO has been used to assess life-threatening conditions during pregnancy, labor, and puerperium to enable interventions to be focused on the chain of events leading to a woman's near-miss or death [8,9]. Prevention of MNM is now a major focus in countries with a low MMR, as it offers a means to improve the quality of maternal healthcare [10]. Assessment of pregnant women with severe maternal outcomes (SMO), which includes MNM and MD, may contribute to accelerating the reduction of morbidity and mortality [11]. The WHO recommends that countries should closely monitor SMO trends to identify preventable causes as well as system-and provider-related failures [12].
Progress has been made in reducing MD in Hunan province [3]. However, there have been no official reports of SMO or MNM cases in Hunan province. Additionally, regional disparities in maternal and child health persist in areas of China, particularly in hospitals, and no study has explored the incidence of SMO and MNM in different levels of medical institutions. However, evaluation of SMO is an important indicator that can help to improve quality of maternal care [13].
This study aimed to compare the incidence and epidemiological characteristics of SMO cases in selected level 2 and 3 hospitals in Hunan province, China, from January 1, 2012 to December 31, 2018. It is important to understand the incidence and epidemiology of SMO cases in different institutions to provide a basis for the government when developing policies concerning prevention of maternal deaths and improvement of obstetrical diagnosis and treatment across different levels of medical and health institutions.

Methods Aim
This study aimed to analyze the differences in incidence and epidemiological characteristics of SMO cases between level 2 and 3 hospitals in Hunan province, China, from 2012 to 2018.

Research Design
This study used a prospective descriptive design based on data for Hunan province collected from

Participants' Characteristics
The participants evaluated in this study were pregnant and postpartum women admitted to the obstetrics departments or intensive care units of the studied institutions, and those who died in hospital. We excluded pregnant women hospitalized in departments other than obstetrics and those with minor abdominal pain but no other obstetric complications. Women that required only embryo preservation (e.g., after in vitro fertilization procedures) and traditional Chinese medicine treatment were also excluded.
The study population included all women during pregnancy, childbirth, or within 42 days of termination of pregnancy regardless of age. Identification of MNM cases was based on the presence of 25 organ and system dysfunction criteria (cardiovascular, respiratory, renal, coagulation, hepatic, neurological, and uterine) via clinical-, laboratory-, and management-based parameters. We defined MNM cases as "a women who nearly died but survived a complication that occurred during pregnancy, childbirth, or within 42 days of termination of pregnancy." MD was defined as "the death of a woman while pregnant, or within 42 days of the termination of pregnancy, irrespective of the duration and site of the pregnancy, from any cause related to, or aggravated by, the pregnancy or its management but not from accidental or incidental causes" [14]. The NMNMSS sampling methods have been described in detail elsewhere [15]. Doctors responsible for patient care within each facility were trained to collect and record the main information for maternal cases admitted to the obstetrics departments from admission to discharge. The information collected included maternal socio demographic characteristics, pregnancy termination conditions or complications, rescue measures and procedures, and maternal and perinatal outcomes during pregnancy, delivery, and post-partum. Collected data for women that met the inclusion criteria were entered into the NMNMSS. Quality assurance was ensured by county-, municipal-, and provincial-level maternal and child health hospital staff. If surveillance hospital errors exceed a predefined standard (e.g., if obstetric complications were under-reported by more than 5%, MD was under-reported by more than 1%, or MNM was under-reported by more than 5%), they re-examined all data in the process of quality checking. We reviewed relevant NMNMSS data from January 1, 2012 to December 31, 2018. Next, we exported data from the NMNMSS to IBM SPSS version 20.0 for our analyses. In total, data of 1817 SMO cases from 541128 hospitalized pregnant women were used to analyze in this study. Frequency tables and cross tabulations by level 2 and level 3 hospitals were produced based on the collected demographic and clinical variables. All statistical tests were considered significant at P < .05. This study was approved by the Ethic Review Committee of Hunan Province Maternal and Children Health Care

Data Collection
Hospital. The requirement for obtaining informed consent was waived because of the retrospective design of this study. This study was carried out in accordance with the principles of the Declaration of Helsinki. Hunan Province Maternal and Children Health Care Hospital is a comprehensive maternal and child care institution responsible for women's and children's healthcare in Hunan province.

Incidence of SMO
During the 7-year period, 541,128 pregnant women were hospitalized in the 17 studied hospitals.
The total MMR was 10.38 (95%CI: 6.95-14.90) and 15.92 (95%CI: 11.51-21.95) per 100,000 LBs in level 2 and 3 hospitals, respectively. In level 2 hospitals, the total MI was 5.60% and the MNM ratio was 16.86. In level 3 hospitals, the total MI was 2.85% and the MNM ratio was 34.11. A summary of deliveries and SMO and MNM indicators in level 2 and 3 hospitals is presented in Table 1  institutions had a history of cesarean section delivery. There was no difference in the marital status in SMO cases by hospital level (χ 2 = 2.65, P = 0.104) ( Table 2).  hospitals, excluding unclassified complications. These outcomes are shown in Table 4 and Fig. 2.

Severe maternal outcomes
The WHO has initiated a process of agreeing on a definition and developing a uniform set of identification criteria for MNM cases, with the intent of facilitating reviews of these cases to monitor and improve the quality of obstetric care [10]. Our study showed the prevalence of MNM was 0.175%  [25]. In sub-Saharan Africa, the MMR was 351 per 100,000 LBs, which was similar to that in south Asia (336 per 100,000 LBs) [26]. Over the past few decades, substantial progress has been made in safe motherhood, possibly attributable to delivery in hospital policies and prevention and treatment of postpartum hemorrhage programs, although regional inequality persists.
Indicators such as the MNM:MD and MI are also used to describe obstetric care. The MNM:MD represents the proportion of MNM cases that progressed to MD, with a higher ratio reflecting better quality of care [5]. In this study, the MNM:MD was 16.86 and 34.11 in level 2 and 3 hospitals, respectively. Therefore, one MD occurred for every 17 MNM cases in level 2 hospitals and for every 34 MNM cases in level 3 hospitals. MNM cases are more likely to die in non-developed and developing countries than in developed countries. A study conducted in Somaliland and Tanzania using similar WHO criteria reported the MNM:MD was 6.7 [27,28]. However, studies conducted in South Africa such as Nigeria, Tanzania, and Ghana and Pakistan reported near ratios ranging from 1.5 to 5 [21,26,29].
The ratios in our study were relatively high in the context of existing policies to promote maternal and child health.
Our findings revealed a MI of 5.6% in level 2 hospitals and 2.85% in level 3 hospitals, which was comparable to the 4.2% MI reported in previous studies conducted in China and Malaysia [19,30]. A low MI (< 5%) indicates better quality of care, with fewer women with severe conditions dying; in contrast, a high MI (> 20%) indicates low quality obstetric care for severe cases, in which more women with severe conditions die [5].
Based on our comparison of these four indicators, we concluded that level 3 hospitals have a stronger medical treatment ability and better healthcare quality. We suggest upgrading the obstetric emergency treatment capacity in level 2 hospitals or to re-distinguish the

Demographic Differences And Birth Outcomes
This study mainly compared women admitted to level 2 hospitals with those admitted to level 3 hospitals. Overall, the proportion of giving birth to a second child was highest in SMO cases. The phenomenon is due to the background of two-child policy opening and high cesarean section rate in China. The main differences found in the demographic comparisons were in the number of antenatal visits and history of cesarean section. SMO cases in level 3 hospitals had more antenatal visits and a higher proportion of cesarean sections than SMO cases in level 2 hospitals. In addition, 33.35% of all SMO cases were women with a history of cesarean section, which was less than the 58% reported in a study at a tertiary referral teaching hospital in the southeast of Iran [31]. Although previous cesarean delivery is not considered a risk factor for SMO or adverse perinatal outcomes, there could be differences between study groups in terms of healthcare-seeking behavior, referral mechanisms, intrapartum monitoring, and clinical decision making [32]. Considering that level 2 hospitals are located in rural areas and level 3 hospitals are located urban areas, there were fewer antenatal visits for pregnant women living in rural areas. This may be related to health awareness. It may be necessary to improve maternal health knowledge and focus on behavior change in low-resource and limited literacy settings, which may contribute to reductions in maternal mortality [33].
Among the 1817 SMO cases in this study, 51% cases delivered at 37-42 gestational weeks, 68% cases delivered by cesarean section, and 88% of women were giving birth for the first time. Most newborns were LBs and term infants. Several studies have shown that the presence of MNM in women is strongly associated with the occurrence of adverse perinatal outcomes, such as stillbirth, preterm birth, low birth weight, and early neonatal mortality [34][35][36][37]. However, studies that quantified the effect of MNM on adverse perinatal outcomes are scarce in China. We intend to explore this issue in a further study.

Clinical Disorders
Hypertensive disorders and neurologic dysfunction were responsible for most MD cases in level 2 hospitals, whereas anemia and coagulation dysfunction were most common in MD cases in level 3 hospitals. However, for MNM cases, anemia and coagulation dysfunction were the leading cause of death in both level 2 and 3 hospitals. We found the major causes of SMO were anemia, hypertensive disorder, and obstetric hemorrhage. Hypertensive disorder and cardiovascular dysfunction were the most frequent conditions among MNM cases in Alborz province of Iran, where medical resources are undeveloped [38]. In the stetting of the present study, hypertensive disorders related to MNM cases in level 2 hospitals and anemia in level 3 hospitals need more attention to prevent SMO cases in Hunan province. Anemia in pregnancy is associated with severe maternal morbidity and is an indirect cause of MD across pregnant populations in both low-and high-income settings [39]. The high prevalence of anemia also contributed to adverse outcomes in women with prenatal hemorrhage. It is therefore crucial to optimize maternal iron status to improve maternal outcomes [40]. Postpartum hemorrhage was less common in the present study compared with other studies, which may be because of the high coverage of essential medical interventions to prevent this condition.

Limitations
We applied the unified WHO maternal near miss criteria in different-sized hospitals, which might have resulted in information bias because of differences in diagnostic capabilities and standards. Second, we used facility-based sampling, which could have introduced referral bias. Third, some related risk factors associated with MNM such as pre-pregnancy body mass index, diseases before pregnancy, and family history were not collected in this study.

Conclusions
The study shows higher ratios of MNM and MD cases in level 3 hospitals compared with level 2 hospitals. The obstetric emergency capacity of level 3 hospitals is higher than that of level 2 hospitals. Our findings suggest future government policies should consider upgrading the obstetric emergency treatment capacity in level 2 hospitals or to re-distinguish the social functions of different medical institutions. MMR:maternal mortality ratio.

Declarations
Ethics approval was obtained from Hunan province maternal and children care hospital.

Consent for publication
Not applicable.

Availability of data and materials
The datasets used and/or analyzed in the present study are available from the first author on request.
19 (12):781-785. Figure 1 The time trend of MNM ratio, MI, maternal mortality, and MNM:MD in women admitted to level 2 and 3 hospitals in Hunan province from 2012 to 2018.