The ecology model of medical care was first introduced in 1961 [
Ecology is applicable to clinical medicine in which structure and dynamics among the medical personnel, disease prevalence, and health care system should be taken into consideration. For example, it will establish a balance between medical system providing all sites of care in a region and the portion of population who needs medical care according to the disease severity. Likewise, it also balances health care seeking behavior of people with the actual health service utilization.
From the obstetric viewpoint, routine care for low-risk women belongs to primary care, some women with high-risk factors need specialized care requiring high-level perinatal centers, and some women need emergency transfer to tertiary centers due to severe complications of the mother and infant. However, application of the ecology model to obstetric care has not been performed using a population-based approach. Thus, we hypothesized that this ecology model is applicable to a system providing perinatal care in Japan, where primary caregivers deal with low-risk pregnancies and high-level centers take charge of high-risk pregnancies to improve good maternal and childhood outcomes. Japan is unique to have ethnically almost homogeneous population and to have a universal health care system that allows everyone to access freely to hospital. Besides, we have a standardized perinatal care system, in which each medical district of 1 million population has 1 tertiary center with several affiliated secondary centers, in which high-risk women are transferred from regional primary hospitals. If the ecology model is applicable to perinatal care, it will enable us to arrange an appropriate framework under the balance between the health care demands and supplying medical personnel.
This study was approved by the Institutional Review Board, Faculty of Medicine, University of Miyazaki.
In 1997, we started a regional population-based study on all perinatal deaths in Miyazaki prefecture, where we have 10,000 deliveries per year in a population of 1 million. Details of the study have been reported elsewhere [
When antepartum high-risk factors are diagnosed, women are advised to visit high-level perinatal centers where they finally deliver their babies. High-risk factors include prenatal medical complications such as diabetes, obstetric complications such as hypertensive disorders, and fetal complications such as growth restriction. Additionally, some emergencies may occur and they are transferred to the 8 high-level centers. To determine the reasons for emergency transfer, a questionnaire was sent and, if necessary, we directly reviewed the medical charts and interviewed the physicians in charge.
We used the above-mentioned data from 2001 to 2005 and applied them to the ecology model [
Prevalence of risk-allocated persons per 1,000 was compared by Chi-square test and
From 2001 to 2005, we had 53,461 deliveries and 235 perinatal deaths (4.40/1,000) including 158 fetal deaths and 77 neonatal deaths. The 34 primary hospitals dealt with 42,080 (787/1,000) low-risk deliveries, 7 secondary centers had 9,887 (185/1,000) deliveries with some high-risk factors, and 1 tertiary center had 1,494 (28/1,000) deliveries with the most high-risk factors. We also had 1,504 emergency transfers to high-level institutions (28/1,000), among which 192 (13%) were maternal indications and the remaining 1,312 (87%) were fetal indications. Among these cases, 89 required a university-setting care, which accounted for 1.7/1,000 of all deliveries (Table
Prevalence of risk-allocated persons per 1,000 in each study.
Original | Revisited | Miyazaki | Tokyo | |
---|---|---|---|---|
Primary hoptital | 750 | 783 | 787 | 301 |
Secondary center | 235 | 195 | 185 | 494 |
Tertiary center | 14 | 21 | 26 | 204 |
Emergency transfer to tertiary center | 1 | 1 | 2 | 1 |
Total | 1,000 | 1,000 | 1,000 | 1,000 |
Miyazaki versus Original, (
Tokyo versus Original, Revisited, and Miyazaki, (
In Tokyo, they had 106,613 deliveries in 2009 [
The average perinatal mortality rate of Tokyo was 5.06/1,000 during 2001 to 2005 [
Table
The emergency maternal transfer rate to the university-settings was similar between Miyazaki (1.66/1,000) and Tokyo (1.46/1,000). However, overall maternal transfer rate to high-level centers was not available in Tokyo. The difference in the overall maternal transfers may contribute to some extent to the differences in perinatal mortality rates, which need further studies.
Since the prevalence of risk-allocated persons was not different between the original and updated data (Table
Ecology curves showing the relationship between patient number per 1,000 as a function of perinatal care levels. There is similarity between the combined original ecology curve (solid) and that for Miyazaki data (dotted). However, the curve derived from the Tokyo data (doublet) is apparently different from the original curve.
The differences in ecology curves between Miyazaki and Tokyo are unexplained in the present study. One possibility is that the number of primary hospitals has been decreasing in Tokyo, while it is relatively stable in Miyazaki. Another possibility is that pregnant women’s behavior is different in that women in Tokyo prefer high-level institutions to primary hospitals even though they do not have high-risk factors. Women in Miyazaki more likely follow the policy that low-risk women should be cared for in primary hospitals.
The specialized application of the ecology model to pregnant women has not been previously performed using a population-based approach, which would provide a useful framework for organizing health care, medical education, and research. We introduced a new concept of ecology curve (Figure
Good childhood outcomes are achieved along with our perinatal risk-allocation system, where low-risk pregnancies are cared for by primary hospitals (80% of all deliveries) and high-risk pregnancies by high-level centers. Thus, we speculate that applying the original ecology model to the perinatal medicine is beneficial to provide a useful framework for organizing perinatal care system. If low-risk women bypass the primary hospitals to secondary or tertiary centers, the dynamics of this ecology model may be destroyed and perinatal outcome would become poorer.
Our population-based data showed remarkable similarity between the prevalence of high-risk pregnancies and the prevalence of required medical care in the original ecology model, resulting in remarkable similarity in ecology curves as shown in Figure
The authors are grateful to all the members of Miyazaki Perinatal Data Group for their contributions to data sampling. This study was funded by a Grant no. 79-258 from the Ministry of Education, Culture, Sports, Science, and Technology, Japan and a Grant from the JAOG Ogyaa Donation Foundation, Japan.