With the change in China's national conditions, the birth policy has been adjusted accordingly. On January 1, 2016, the "two-child policy" was fully implemented. Although it has largely solved social problems such as the "ageing population" and the "imbalance in the ratio of males to females", it has also resulted in more severe consequences. In particular, the high rate of caesarean section in China more than a decade ago has resulted in a serious problem: the dangerous placenta previa in the second pregnancy caused by scars in the uterus, the increased incidence of placental implantation, and the increased risk of massive haemorrhage during labour and the postpartum period.
1. In this study, there was an increase in the number of elderly mothers, especially the proportion of women aged over 40 years. The number of parturient women increased significantly, from 47.8–67.8%. The reason is that after the full implementation of the "two-child policy", many women who did not plan to have another child during childbearing age chose to have a second child. According to the research results of HongXia Zhang et al[7], after the "two-child policy" was fully implemented, the percentage of pregnant women over the age of 40 increased from 2.2–3.6%, and the percentage of pregnant women aged over 40 increased from 17.0–30.0%. The cases we collected were all critical cases transferred to the ICU, and there were more cases of patients with advanced age. Most of these cases had a longer time interval than the previous delivery, and there might be many physiological problems associated with reproduction, such as increased complications such as pre-eclampsia and gestational diabetes [8–9].
2. Postpartum haemorrhage was the primary disease resulting in transfer to the ICU from the obstetrics department, accounting for 52.3% (139/266). This prevalence was followed by 32.3% (86/266) of pregnancies complicated by medical diseases, including preeclampsia/eclampsia and HELLP syndrome (14.7%) (39/266). In the control group, postpartum haemorrhage was also the main disease resulting in transfer to the ICU, accounting for 45.9% (96/209). This prevalence rate was followed by 35.9% (75/209) of pregnancies with medical conditions, with preeclampsia/eclampsia and HELLP syndrome accounting for 19.6% (41/209). In the multicentre study of Zhiling Zhao et al[10], during the nine-year study period from 2008 to 2016, the major diagnoses associated with obstetric transfer to the ICU were postpartum haemorrhage (170/491, 34.6%), gestational hypertension (156/491, 31.8%) and cardiovascular and cerebrovascular diseases (78/491, 15.9%). Relevant foreign studies also suggested that the major diseases associated with the transfer from the obstetrics department to the ICU were "postpartum haemorrhage" and "gestational hypertension" [11–13]. In our early investigation and evaluation of critical obstetric diseases [14], 25.7% of the cases had medical or surgical diseases, 23.8% had postpartum haemorrhage, and 23.8% had gestational hypertension. According to a study by Sultan et al. [15], preeclampsia/eclampsia and HELLP syndrome were the main reasons for obstetric transfer to the ICU, followed by postpartum haemorrhage. In this study, the proportion of postpartum haemorrhage was significantly higher, which was related to the significant increase in cases of elderly puerpera, placental implantation and scarred uterus after the comprehensive implementation of the "two-child policy". Such cases were more prone to uterine contraction weakness and postpartum haemorrhage caused by placental factors. In addition to the abovementioned three diseases, acute pancreatitis, AFLP, acute appendicitis, acute peritonitis and other pregnancy complications including surgical diseases, infection and perinatal cardiomyopathy were the common causes of critical illness among pregnant women in this study.
3. After the full implementation of the "two-child policy", an especially high rate of caesarean section was observed in China more than 10 years ago, and the serious complications related to caesarean section associated with these pregnant women's second birth have attracted increasing attention, especially the risk of placental implantation. Many studies have shown [16–18] that scarred uterus is an independent risk factor for placental implantation. In this study, of the 146 cases of postpartum haemorrhage, 90 were placental implantation (90/146, 61.6%) and 46 were hysterectomy (46/146, 31.5%). Among the 88 cases of postpartum haemorrhage in the control group, 42 cases were placental implantation (42/88, 47.7%), and 23 cases underwent hysterectomy (23/88, 26.1%). In this study, the proportion of individuals with postpartum haemorrhage who were transferred to the ICU was high, including 112 cases of postpartum haemorrhage (112/266,42.1%), which may be related to placental implantation in Peking University Third Hospital [19], and placenta previa and placental implantation are one of the common causes of postpartum haemorrhage [20]. Our study found that 90 (90/146,61.6%) of the 146 cases of postpartum haemorrhage in the study group were mainly caused by placental implantation. Although the prevalence increased, the operation difficulty was greater, but the prevalence of bleeding more than 5000 ml decreased significantly. The prevalence of a blood transfusion amount greater than 2000 ml was significantly lower than that in the control group. The difference was statistically significant (P < 0.05). The operation skill and experience was improved, and we standardized the antenatal examination, health education, and government to develop critical maternal referral standards and reduced the level of bleeding emergency rescue referral of patients.
4. After the full implementation of the "two-child policy", the incidence of placenta previa and placental implantation was greatly increased in women who had undergone caesarean section who had a second pregnancy. Studies have suggested that placenta previa is an independent risk factor for active total hysterectomy [21], especially for placenta previa with placental implantation [22]. In patients with placental blood circulation of 700 ml/min (500 ~ 1 200 ml/min), when the uterus treatment result is bad, hysterectomy has become the main measure of postpartum haemorrhage treatment for placenta increta merger [23–25], especially when the placenta extends through the uterine serosa layer and adjacent tissues (including broad ligament, rectum and bladder); a whole hysterectomy should be timely and decisively performed to reduce maternal postpartum haemorrhage-related complications [26]. For this type of situation, we performed a retrospective study [4]. The use of our prenatal ultrasonic examination predicted the placenta increta rating scale, assessment of the severity of placenta increta, and prediction of the risk of intraoperative bleeding and hysterectomy. A score of 5 or more was used to predict adhesion type, and heavy-type (including implant and penetrating) placenta implants were indicated by a score of 0 or 1. The possibility of the penetrative implant type is high. In this study, the hysterectomy rate of postpartum haemorrhage patients in the two groups was elevated (31.5% vs 26.1%), and the difference was statistically significant (P < 0.05).
5. Nosocomial infection is positively correlated with length of stay; the longer the stay, the greater the chance of infection [27]. After the full implementation of the "two-child policy", the fertility rate increased. Methods to shorten the average length of hospital stay are of great significance to alleviate the contradiction between the supply and demand of medical resources and to improve the turnover rate of beds and the quality of medical services. It has been reported in the literature [28] that the length of hospital stay may be affected by various factors, such as the medical expense payment method, delivery method, operation, pregnancy complications, perinatal pregnancy outcome, transfer from other departments to the maternity ward and so on. All cases in this study were critical cases transferred from the obstetrics department to the ICU. The average length of ICU stay in the two groups decreased from 4 days to 2.8 days, and the total length of ICU stay decreased from 15 days to 12 days, all of which were significantly different. The difference was statistically significant, and this difference was related to the strengthened health care awareness of the pregnant women and their families and the improved efficacy of multi-disciplinary joint diagnosis and treatment. A study [29] on multiple factors of maternal hospitalization costs showed that the length of hospital stay, delivery mode, postpartum and postpartum pathological conditions, age, and presence of pregnancy complications all affect maternal hospitalization costs. In this study, although the length of hospital stay in the study group was shortened, the average hospital stay cost did not decrease but rather increased (38,700 yuan vs 34,300 yuan), which may be related to the increase in the number of elderly puerpera, parturient women and placental implantation after the implementation of the "two-child policy".
6. With the full implementation of the "two-child policy", the rapid development of assisted reproductive technology, older age, and maternal populations at risk, critically ill obstetric patients increased year by year [10], and severe maternal outcomes during pregnancy and birth are more likely to result in emergencies and accidents; these women are prone to multiple organ failure, and the ICU can perform early recognition and intervention in patients with critical obstetric conditions and perform comprehensive rescue and provide organ function protection and support therapy, thus improving the critical maternal treatment success rate. However, methods to integrate the diagnosis and treatment of critically ill pregnant women into the effective monitoring and management system to reduce maternal deaths are of great significance. Medical institutions in different countries lack uniform standards for the assessment of critically ill pregnant women. Different regions and hospitals in China have different diagnostic standards for critically ill pregnant and inpatient women, making it difficult to evaluate and compare the medical quality received by critically ill pregnant and inpatient women as a whole. This research adopted the WHO near-miss scoring criteria [30] for critical degree evaluation. In 2009, the WHO combined clinical indications, organ dysfunction, inspection index and clinical treatment in three aspects, such as content distribution, and in 2011 formulated the near-miss guide, and the critical maternal interventions to evaluate the proposed system process intend to look forward through the analysis of serious maternal medical process, medical measures to implement, and whether there is a problem; the transfer process improves the level of critical maternal treatment [31]. Lima H M P[32] et al conducted a secondary analysis of data collected in a multicenter cross-sectional study in Brazil and found that the diagnostic criteria of the WHO near miss were highly effective in the diagnosis and treatment of critically ill pregnant women and could effectively reduce maternal deaths. Skandarupan J et al[33] conducted a prospective study in three Australian hospitals using the WHO near miss scoring standard and found that this standard could be more effective for evaluating critical obstetric diseases such as postpartum haemorrhage and preeclampsia and effectively reduce maternal mortality. In this study, 83.5% (222/266) and 76.6% (160/209) of the study group and the control group met the critical care score standard, respectively, which was consistent with a previous study in our hospital (74.3%) [14]. Combined with our earlier studies and evaluation of the validity of the WHO diagnostic criteria, the WHO near-miss criteria have a higher diagnostic validity for patients with critical obstetric diseases and is more effective for reducing maternal deaths.