Data Resource Profile: Xiamen registry of pregnant women and offspring (REPRESENT): a population-based, long-term follow-up database linking four major healthcare data platforms

REPRESENT is the first population-based, long-term follow-up database of pregnant women and their offspring in China that can capture information on a diversity of exposures before pregnancy as well as long-term outcomes for both mothers and infants, in addition to tracking data during gestation and delivery. In the past 11 years (January 2008 to March 2019), REPRESENT has accumulated data concerning 766 194 pregnancies and 765 746 newborns, with over 800 variables being documented from four healthcare data platforms in Xiamen, a sub-provincial city in southeast China that has 4.11 million residents. REPRESENT was primarily built upon the Maternal and Child Health Management Platform, a pregnancy registry which stores healthcare data—including antenatal care, delivery care, postpartum follow-up and childhood follow-up—from pregnant women and their offspring across all maternity departments in Xiamen. By using a unique identifier, REPRESENT linked the pregnancy registry with three other healthcare data platforms, which store healthcare data from 15 tertiary and 2 secondary hospitals, 39 primary healthcare facilities and 272 (of the 281) health stations in the city. The scope of the database spans from pre-pregnancy exposures to post-delivery information about health care and outcomes for mothers, and the follow-up for offspring may cover adolescence and adulthood. Research institutions can apply to access the registry data by submitting a formal study protocol, subject to the approval by Xiamen Health and Medical Big Data Center and Chinese Evidence-based Medicine Center (http://www.xmyys.com.cn/news_info_204.html). Ethical review and research registration are mandatory for all studies. As the nation with the largest population of >17 million newborns annually,1 China always places maternal and child health on its priority research agenda.2 During the past decades, substantial interventional works have led to a large reduction in maternal and infant mortality.3,4 With the introduction of a national goal of Healthy China 2030,5 the research paradigm has now shifted and expanded to the improvement of overall health, such as reduction of newborn and infant malformations, and lowering of serious pregnancy-related complications. This paradigm shift is particularly relevant to address new challenges for advanced-age mothers since the implementation of China’s two-child policy.6 Such challenges include the necessity to answer policy-relevant questions in a timely manner, the limited resources available to deal with rare but serious adverse birth events, and the lack of scientific evidence to causally determine the relationship between pre-pregnancy exposures and long-term health outcomes. The advancement of digital technology in the past decade has enabled electronic collection and storage of healthcare data in China.7,8 The National Health Commission has also enforced the capturing of healthcare data for women and children, such as maternal death, under-5 mortality and birth defects.9 Xiamen, a sub-provincial city of >4 million residents, is unique in the governance of healthcare data in China. Through a central coordination system, electronic health records are centrally collected from primary to tertiary care institutions within the region, whereby the same electronic health records system is adopted across all primary care institutions, and a unique pregnancy registry has been established. It is thus feasible to utilize such integrated data sources to generate trustworthy evidence on pregnancy and child care, spanning several years before and after pregnancy, and providing valuable information about mothers and their offspring. In this data source profile, we report our efforts to develop the Xiamen registry of pregnant women and offspring (REPRESENT) that links four major healthcare data platforms in the region. Xiamen is a coastal city located in southeast China, with a subtropical monsoon climate at an average annual temperature of 21°C. The sub-provincial city is economically administered by the central government of China, and the total population of permanent residents is 4.11 million. The city comprises 6 administrative districts, 38 sub-district units, 364 residential communities and 147 villages. Xiamen currently maintains 15 tertiary hospitals (defined as those with >500 beds), 2 secondary hospitals (between 100 and 499 beds), 39 primary healthcare facilities and 281 health stations (Figure 1). Population coverage and location of hospitals at the end of 2018 in Xiamen city. Shading represents the population coverage of permanent residents in each district (10 000), circles represent the location of tertiary hospitals, and triangles represent the location of secondary hospitals Since 2006, the government of Xiamen has developed four major healthcare data platforms (Figure 2): (i) Residents Healthcare Management Platform, which integrates data from the other three platforms and serves for making appointments and checking electronic health files by residents (Supplementary Appendix 1A, available as Supplementary data at IJE online); (ii) Primary Healthcare Management Platform, which collects healthcare data from 39 primary healthcare facilities and 272 (of the 281) health stations (Supplementary Appendix 1B, available as Supplementary data at IJE online); (iii) Electronic Healthcare Records (EHR) Platform, which collects EHR data from 15 tertiary and 2 secondary hospitals (Supplementary Appendix 1C, available as Supplementary data at IJE online); and (iv) Maternal and Child Health Management Platform, which collects healthcare data from pregnant women and their offspring across all maternity departments in Xiamen. Four major healthcare data platforms in Xiamen. These databases are linked through the Citizen Health Information number (a unique ID). The REPRESENT registry comprises of data from the four databases, with the Maternal and Child Health Management Platform as the primary data source Xiamen residents are given a healthcare card with a unique Citizen Health Identification number, linked to their citizen identity number. They are required to use the healthcare card for making medical appointments, either in person at the reception desk of the healthcare institution or through the Management Platform, which has computer or mobile portals. The identification number enables the linking of data across different platforms. Xiamen Health Commission holds primary responsibility for the development and management of the platforms, data coordination, transfer, uploading and storage, as well as quality control. The Xiamen Health and Medical Big Data Center, under the governance of Xiamen Health Commission, is responsible for technical operation of the platforms. The establishment of REPRESENT commenced with setting up the pregnancy registry, primarily based on the Maternal and Child Health Management Platform. This registry was then linked to the three other platforms. Such data linkage enables longitudinal follow-up of pregnant women and their offspring. The scope of the database spans from pre-pregnancy exposures to post-delivery information about health care and outcomes for mothers, and the follow-up for offspring may cover adolescence and adulthood. The current database has accumulated 11-year data ranging from 2008 to 2019, and the ongoing accumulation of data would enable a great potential for life-course coverage. Table 1 summarizes the sample size and duration time for each data panel and its subset categories. A total of 766 194 pregnancies are registered at Maternal and Child Health Management Platform, including 4 771 235 records of repeated antenatal visits and 3 266 906 records of antenatal screening. In addition, 758 237 pregnancies in maternal delivery care and 765 746 newborns in neonatal delivery care are documented. Sample size and duration time of data panel and subset in the Maternal and Child Health Management Platform Sample size and duration time of data panel and subset in the Maternal and Child Health Management Platform Table 2 presents maternal and offspring characteristics at baseline and key information of the REPRESENT database. The median registrations per year was 55 765 [lower quartile (QL)–upper quartile (QU), 35 020–96 973], and the average maternal age was 27 (25–30) years. A total of 328 375 (46.29%) pregnancies were multipara and 245 822 (32.49%) deliveries were by caesarean section. Maternal and offspring characteristics at baseline and key information of REPRESENT database QL, lower quartile; Qu, upper quartile; N/A, not applicable. Gravidity refers to the number of pregnancies, including current and past pregnancies, no matter whether the pregnancies were interrupted or resulted in a live birth. Parity refers to the number of deliveries of a fetus at or after 24th gestational weeks, regardless of live birth or stillbirth. Nullipara indicates that a woman has no birth history, and multipara means a woman had more than one birth. No. (%). The number of pregnancies in antenatal care (766 194) is the denominator. The number of pregnancies in maternal delivery care (758 237) is the denominator. The number of newborns in neonatal delivery care (765 746) is the denominator. Maternal and offspring characteristics at baseline and key information of REPRESENT database QL, lower quartile; Qu, upper quartile; N/A, not applicable. Gravidity refers to the number of pregnancies, including current and past pregnancies, no matter whether the pregnancies were interrupted or resulted in a live birth. Parity refers to the number of deliveries of a fetus at or after 24th gestational weeks, regardless of live birth or stillbirth. Nullipara indicates that a woman has no birth history, and multipara means a woman had more than one birth. No. (%). The number of pregnancies in antenatal care (766 194) is the denominator. The number of pregnancies in maternal delivery care (758 237) is the denominator. The number of newborns in neonatal delivery care (765 746) is the denominator. In an effort to protect the health of mothers and offspring, the National Health Commission of China has implemented rigorous pregnancy management since 2011.10 All the maternal departments in Xiamen have followed two guidance documents, issued by the National Health Commission, to develop the pregnancy registry and conduct follow-ups, including Administrative Regulation on Health Care during Pregnancy and Childbirth and Good Practice for Health Care during Pregnancy and Childbirth.10 Thus, pregnancy care in Xiamen follows a standard protocol (Figure 3). Standard protocol of pregnancy care pattern in Xiamen After confirmation of conception by ultrasonography, a pregnant woman is registered at the Maternal and Child Health Management Platform by each clinician at the first antenatal visit, and a unique pregnancy registration number is assigned. The woman is subsequently assessed by a clinician using a maternal risk score, and her pregnancy is categorized as either low risk (without any high-risk characteristics) or high risk (with any high-risk characteristics).11 Following the initial assessment, antenatal care for low-risk pregnancies is conducted at primary or secondary healthcare facilities until 20 weeks of gestation; if any complication occurs, the woman is transferred to a tertiary hospital. Nuchal translucency examination is conducted at a tertiary care institution. Commencing at 21 weeks of gestation, all antenatal care and follow-up visits are carried out at tertiary hospitals until delivery. High-risk pregnancies are always managed at tertiary hospitals. Typically, pregnant women undertake antenatal visits every 4 weeks during the first and second trimesters. From the third trimester (i.e. after 28 gestational weeks), the interval of antenatal visits is usually 1–2 weeks depending on the condition of pregnancy. As required by the Health Commission, information about all the visits are strictly documented by clinicians and stored in the Maternal and Child Health Management Platform in a timely manner. After delivery, maternal family visits by primary health workers occur at 5 days and infant family visits at 30 days, as well as maternal examinations at 42 days at qualified maternity departments. For women and infants with comorbidities, additional family visits may be conducted. The infant family visit at 30 days after delivery has been effective in Xiamen since 2010, whereas maternal family visits at 5 days after delivery began in 2014. The maternal examination at 42 days was initiated in 2013 on a voluntary basis. Following the consistent and recommended follow-up workflow from conception to postpartum (Figure 3), the pregnancy registry was developed based on the Maternal and Child Health Management Platform. This platform has been effectively used for managing maternal and child health across all healthcare institutions in Xiamen (accessed by attending clinicians through a fixed internal portal), which documents information and events about pregnant women from registration at their first trimester to postpartum, and includes childhood follow-up records. A birth certificate linking parental information is also automatically generated from this system. Attending clinicians report their assessment by completing specific forms of the platform, while pregnant women can also review their health reports through this system, as well as making appointments or booking a maternity bed. Currently, the pregnancy registry consists of four data panels, namely, antenatal care, delivery care, postpartum follow-up and childhood follow-up (Table 3). Of those, the antenatal care panel is concerned with registration visit, regular antenatal visits and antenatal screening. The delivery care panel comprises maternal and neonatal delivery records, where pregnancy termination outcomes and birth defects are separately documented. Any pregnancy loss, including abortion, induced labor, stillbirth/fetal death and the reasons for termination of pregnancy that occurred after the first antenatal visit, is recorded into a separate sheet by clinicians. The postpartum follow-up panel includes maternal family visits at 5 days after delivery and infant family visits at 30 days by primary care clinicians, as well as maternal examination at 42 days at maternity departments. The childhood follow-up panel is not part of the pregnancy care and is not conducted at maternity departments. However, all childhood data are collected through the Maternal and Child Health Management Platform and linked to the three other panels. In the first 3 years, the follow-ups are conducted at 1, 3, 6, 8, 12, 18, 24 and 36 months. After 36 months, the follow-ups are undertaken by primary care physicians annually at kindergartens until the child is 6 years of age. Data panels and key variables in the REPRESENT registry Data panels and key variables in the REPRESENT registry Since its inception, Xiamen Health Commission has implemented a rigorous approach to enforce data collection and quality control. During pregnancy, attending staff (clinicians, midwives and nurses) are required to file antenatal care visits through the Maternal and Child Health Management Platform. Information is manually entered by attending staff, except laboratory test data which are automatically uploaded. The original imaging records are saved locally, but the key diagnostic information is automatically uploaded to the platform. After delivery, details on delivery care including maternal and neonatal records are completed electronically by attending clinicians. Any diagnosed birth defect must be filed separately. Postpartum follow-ups are completed according to the pre-specified protocol by attending clinicians or general practitioners (GPs). The pregnancy registry offers a core data repository to construct a longitudinal follow-up of pregnancy care and outcomes from conception to postpartum and newborn tracking, as well as childhood follow-ups (up to 6 years). To develop REPRESENT, we linked the pregnancy registry with three other data platforms to increase data diversity and the length of follow-up. The current REPRESENT database has accumulated 11-year data (i.e. 2008–2019) and has the capacity to prolong follow-up with ongoing efforts of data accumulation from the four databases. As a result, one would be able to track pregnant women from pre-conception to a decade or longer after delivery, thus enabling long-term follow-up. Specifically, data are available both for exposures (e.g. historical diseases, medications, healthcare service and environmental factors) and long-term healthcare use and outcomes after delivery (Figure 4). Linking pregnancy registry with other data Electronic Healthcare Records the offspring to be followed up to by linking the databases, as each newborn is a Citizen Health Information number at which is used or her Thus, by linking databases, the health information of the offspring be over a (Figure 4). In addition, the offspring may be linked to their mothers by the family relationship in the Residents Healthcare Management Platform. identification are stored in the four platforms, including for Citizen Health Pregnancy number, and other used identification across different institutions (e.g. medical institution number, number and linked the pregnancy registry with the other platforms primarily by the Citizen Health In of any identification number, is based on other variables such as birth delivery medical institution number, number and number. 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By linking four major healthcare data platforms, one can capture information on a diversity of exposures before pregnancy as well as long-term outcomes for both mothers and infants, in addition to tracking data during gestation and delivery, which the to the between before and during pregnancy (e.g. and and long-term outcomes. one may access a large and of healthcare information spanning from gestation to postpartum and childhood follow-ups, which not pregnancy information at each maternity in Xiamen, but also includes a of information about medical laboratory and imaging documented according to consistent workflow and The data is substantial with over 800 variables being documented. In the past 11 years (January 2008 to March REPRESENT has accumulated data concerning 766 194 pregnancies and 765 746 the quality of data is of the for data collection implemented by the Health Commission, particularly data collected the Maternal and Child Health Management Platform, which represents the for the pregnancy medical history, gestational history, family and family can be and from four data platforms, which from the Pregnancy It also has several potential A of REPRESENT is the lack of national in of the and between and China, and the characteristics of the Xiamen population may from other To this is our to develop a data platform that links databases across in China by a of institutions in the live birth may be in our as pregnancy (e.g. pregnancy before pregnancy and before are to be In our a separate sheet about pregnancy termination outcomes was which can any pregnancy by clinicians, including abortion, induced labor, stillbirth/fetal death and the reasons for termination of pregnancy, after the first antenatal the risk that both pregnancy and the outcomes of during the may the of live birth In addition, other forms of such as and may be using the database. However, given its as a database and the of variables this database may the available data source for this population in China. The Chinese Evidence-based Medicine Center, with China is responsible for the Chinese Evidence-based Medicine Center and Xiamen Health and Medical Big Data Center are responsible for the use of the registry Research institutions can apply to access the registry data by submitting a formal study protocol, subject to approval by the Xiamen Health and Medical Big Data Center and the Chinese Evidence-based Medicine Ethical review and research registration are mandatory for all studies. Research institutions can apply for access to the registry data by submitting a formal study protocol, subject to approval by Xiamen Health and Medical Big Data Center and Chinese Evidence-based Medicine Center (http://www.xmyys.com.cn/news_info_204.html). Supplementary data are available at IJE The study was by from the National of China National Research and of Health and and National and The would to the and institutions have substantial to the establishment of Xiamen Health and Medical Big Data Center of of of Xiamen Maternal and Child Care and are

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