In the current study, the average MNMR for the ICU admission was 3.5 per 1,000 LBs and accounted for 0.36% when WHO criteria conducted by many obstetric experts were used. The finding was consistent with other developed countries and a recent systematic review that indicated a wide spread of the incidence of MNM for the ICU admission[18–21]. Although only a small percentage of women need to be admitted to the ICU for care, this population is increasing due to population growth and the introduction of new treatment models.
In 2016, China changed its fertility policy from "single two-child " to "universal two-child ", which resulted in the concentrated release of accumulated fertility demand and an increase in the proportion of high-risk pregnant women . The change in delivery volume is consistent with the results in this study. A growing number of women are conceiving with assisted reproductive technology (ART), giving rise to a significantly increased risk of perinatal complications, blood transfusion, and ICU hospitalization . Therefore, we strive to check at the source, pour attention into high-risk pregnant women, and provide the correct advice on the timing of pregnancy again, health care, and precautions during pregnancy.
With the progress of urbanization and the regional characteristics of Yangzhou, the rural population still occupies a considerable proportion. The migrant population with unstable income and lacking medical insurance has also increased overwhelmingly . The government and health institutions should strengthen health education for the migrant population, raise awareness of self-health management, and gradually realize that migrant women enjoy the same health care services as the place where they immigrated .This solution can promote the conversion of a high-risk pregnancy to medium or low risk and effectively reduce the occurrence of MNM.
As expected, 41.5% of pregnant women transferred from other hospitals were admitted to the ICU in this study. These women are facing a higher risk of MNM due to the influence of transportation, referral distance, and primary care level[26, 27].To resolve this contradiction, it is indispensable to establish a two-way cooperative relationship led by the Critical Maternal Emergency Center to ensure the coverage of all midwifery institutions, implement hierarchical referral treatment, and establish the shortest distance green treatment channel. For women with unstable conditions, experts from higher-level medical institutions can provide on-site treatment or telemedicine to guide the rescue.
Irregular prenatal examinations are one of the potential risk factors for MNM . This study stated that the rate of irregular prenatal examinations in the ICU group was almost twice that of the control group, suggesting that regular examinations can prevent adverse pregnancy outcomes and reduce medical costs. It reached an agreement on the results of a retrospective study in Brazil . With the help of the nation’s free five-time prenatal examinations service for pregnant women, we will make full use of pregnant women’s schools and communities to promote the benefits of regular examinations and help pregnant women understand its importance.
During the study period, the previous cesarean section rate was 33.9%. It was lower than the population-based prospective study in Italy, which found that repeated cesarean section was remarkably associated with postpartum hemorrhage and hysterectomy[14, 30]. The number of scarred uterus in China doubled from 2012 to 2016,9.8% and 17.7% respectively. The cesarean section rate in China was the highest among the nine Asian countries, especially the rate of cesarean sections without medical indications . But for MNM admitted to the ICU, the cesarean section is an effective means to relieve adverse pregnancy outcomes . So 92.3% of the delivery methods in this study were cesarean sections. Higher cesarean section rates and changes in fertility policies will lead to the diversification and complexity of diseases, which highlight the need for multidisciplinary treatment. Regular skills training and rescue drills for relevant health care personnel are also key measures.
This study found that the premature birth rate and low Apgar scores at both 1 and 5 minutes were significantly higher than those of MNM in the control group. A document reported that babies delivered by mothers in the ICU have higher neonatal intubation rates, NICU transfer rates and lower Apgar scores . This shows that the ICU health care personnel are facing huge challenges, not only need to pay attention to the physical condition of MNM, but the condition of newborns may also be critical and need to be dealt with in time.
The main obstetric causes of MNM admitted to the ICU were obstetric hemorrhage and hypertension. This finding is in line with the results of several studies conducted in France and inconsistent with several studies in Brazil[35, 36]. Obstetric hemorrhage tends to easily have serious adverse effects on women's physical and mental health. On the one hand, the high rate of cesarean section leads to the invasive placenta , On the other hand, as a treatment center for MNM, the referral of obstetric patients from other hospitals to our hospital results in data bias. Obstetric medical workers should keep eyes on obstetric hemorrhage risk screening, carrying out key monitoring and dynamic management of pregnant women at risk of bleeding.
Our hospital uses prophylactic oxytocin for every parturient to reduce avoidable obstetric hemorrhage. Blood transfusion is an important emergency intervention. The availability of blood and the threshold of use is different in various regions . Hence, ≥ 5 units of red blood cells as the inclusion criteria may not truly reflect the severity of MNM. This requires further research to determine the blood transfusion threshold that meets national characteristics. Hysterectomy is the most serious treatment for obstetric hemorrhage. The higher rate of hysterectomy is related to the delay in seeking medical services and referrals for pregnant women with severe obstetric hemorrhage. [22, 39]. However, in recent years, a reasonable choice of compression suture and uterine artery embolization has effectively reduced the rate of hysterectomy and improve maternal quality of life.
Affected by race, environment, and social economy, 5%-10% of pregnant women will develop hypertension . In this study, 18.8% of MNM admitted to the ICU had hypertension. Study had pointed out that irregular prenatal examinations and low educational attainment were risk factors for hypertension. Our hospital's recognition and treatment of hypertension are relatively complete. high-risk pregnant women with a family history of hypertension ought to be vigilant and screened as soon as possible. Meanwhile, the ability of health care personnel to judge and deal with complications needs to be enhanced.
Although obstetric causes are the main reason for MNM admitted to the ICU [42, 43], considering the development of reproductive medicine and other related medicine, perinatal complications and comorbidities tend to occur in women with underlying diseases, which make the treatments of indirect obstetric causes too complex and beyond the capacity of obstetricians . The main indirect obstetric cause of MNM admitted to the ICU was heart-related diseases, while the control group is epilepsy .According to a national research studied in China, the incidence of MMR caused by heart-related diseases rose by 1.5 per 100,000 between 2013 and 2016. As a tertiary general hospital, our hospital is able to provide comprehensive treatments and advanced intervention measures for women suffering those diseases and use multidisciplinary management to powerfully reduce MMR.
96.9% of MNM were admitted to the ICU after delivery. More than half of MNM spent less than three days in the ICU. Similar to other studies, China’s first multi-center study showed that 92.26% of pregnant women were admitted to the ICU after delivery . 87% of the ICU admissions in the United States occurred postpartum with an average length of 10 days for staying in hospital . The difference in the length of the ICU stay implies that since our hospital has only a comprehensive ICU, most MNM admitted to the ICU only need continuous monitoring and do not necessarily need intensive care. In this case, establishing an obstetric intensive care unit may contribute to reducing the pressure on the ICU and providing specialist nursing for MNM.
During the 5-year study period, there was only one maternal death due to pregnancy complicated by heart failure. MMR is 5/105. Compared with low-income and low-middle-income countries, this incidence reflects our hospital’s good health service management and the availability of high-quality drugs and interventions . Approximately 830 women die from preventable pregnancy-related diseases every day in the world, and 99% of MD occurs in developing countries [47, 48]. It is a valuable method for health care personnel to regularly audit and analyzes MNM admitted to the ICU.
There are some limitations to our research worth noting. First of all, given that this study was conducted in a single hospital, our results may not be generalized to primary and private hospitals. However, most MNM receives treatment in tertiary general hospitals, especially in middle-income and high-income areas. This bias will not have much impact on the result. Secondly, this study is a retrospective study with data from medical records. It is hoped that the occurrence of data loss can be minimized with the exploitation and development of tools for the automatic identification of MNM. Finally, our use of WHO standards may underestimate the number of severe maternal morbidities. In the future ,research is needed to establish MNM standards suitable for our country or region.
To the best of our knowledge, this study is the first retrospective study of MNM admitted to the ICU in Yangzhou. The hospitals in this study have abundant experience in handling pregnancy complications and pay attention to the incidence, risk factors, and causes of MNM, which is helpful to promote the transformation from quantity to quality of obstetric health. Moreover, the 5-year study can objectively evaluate the impact of the "two-child policy" on MNM.