Born and Bred in (BaBi): an efficient, place-based birth e-cohort network

Design

BaBi is a prospective longitudinal cohort study. Recruitment to the study is through a highly efficient embedded consent process administered by midwifery teams, which enables identifiable, routine data from multiple health, social care, and education sources to be linked over a mother and baby’s life. Consent to contact is also gathered, providing a platform to approach recruited participants about future research opportunities. The multi-site nature of the network also facilitates a large-scale meta cohort of harmonised datasets across multiple localities with differing characteristics, providing a data environment capable of supporting research questions generalisable at the national population health level to inform evidence-based policymaking.

To achieve the study aims, each local cohort has the following objectives.

Settings and sites

Each BaBi site is located within a local area in England, UK and is led by a partnership of local services, including National Health Service Trusts and Local Authorities/governments. The founding site was in Bradford, UK. Bradford, a city in the north of England, is the fifth largest Local Authority in England and has a population of >550,000 people¹³. It has a youthful population, with 28.2% of the district’s population aged 17 years or less. There are also high levels of deprivation and ethnic diversity. BaBi Bradford (known locally as BiB4All) opened to recruitment in 2019, and all women in receipt of antenatal care from Bradford Royal Infirmary are eligible to participate. This represents approximately 5,900 women per year. Four further pilot sites (BaBi Wakefield, BaBi Leeds, BaBi Doncaster, BaBi East London) were initially set up to develop the BaBi network, which is managed through a coordinating centre within BiB4All (part of the Born in Bradford programme and hosted at Bradford Institute for Health Research). The BaBi Coordinating Centre coordinates the operations of the BaBi network, including the governance and approval of the protocol and associated documentation. Following the success of the expansion of the BaBi model to the pilot sites, BaBi opened to new sites. At the time of submission, 13 BaBi sites were open to recruitment. An updated list of operational BaBi sites is available at http://www.babinetwork.co.uk/sites

Participants

Figure 1 shows a flow diagram outlining the identification and recruitment of pregnant women.

Figure 1. Flow diagram of the BaBi recruitment process.

Eligibility

All women who are booked to receive maternity care with a participating BaBi site are eligible to join the cohort on behalf of themselves and their expected child at each eligible pregnancy (i.e., a new consent process is initiated at subsequent pregnancies). Women remain eligible throughout their pregnancy and after their babies have been born, until they are discharged from maternity care.

Women who join the cohort and subsequently move out of the area before the birth of their babies will remain in the cohort. Efforts will be made to ensure that all recruited women and their babies are followed up outside the site area in these instances.

Women who experience adverse pregnancy outcomes such as miscarriage, stillbirth, or neonatal death before consenting to join the cohort become ineligible and are not approached to join. Participants who experience adverse pregnancy outcomes following consent will remain enrolled unless they contact the BaBi study team to withdraw.

Participants under the ageof 16 years are eligible. If deemed Gillick competent¹⁴, they can provide self-consent. If not, consent is sought from a parent or guardian, and the participant is approached again to consent (or withdraw) after their 16^th birthday.

Training and staff engagement

All healthcare practitioners approaching and recruiting participants to the study receive training from members of the BaBi study team or directly through e-learning modules designed for the study and freely available through the National Institute for Health and Care Research (NIHR) Learn platform. Training was co-developed with midwives to ensure relevance, understanding, and feasibility. Training focuses on informed consent and follows the principles of NIHR Good Clinical Practice. Additional staff engagement is achieved through regular newsletters, emails, and updates at relevant NHS Trust meetings and forums.

Consent process

The consent process is embedded in routine antenatal care, delivered by trained health care practitioners (predominantly midwives), and documented in the electronic patient record (EPR). Informed consent for the study is obtained verbally from women for themselves and on behalf of their baby. Their consent is recorded digitally in the EPR in a specific consent question designed for the study. Verbal consent was chosen over written consent to align with clinical practice, where consent for many decisions is provided verbally to health care professionals and recorded digitally by them in the EPR. This method of consent was co-produced with women and midwives to ensure that the process was acceptable, ethical, informed and efficient. Consent can occur at any point during or just after birth up to the point of discharge from maternity services. In addition to consenting to access and link routinely collected data, potential participants are asked to consent to be contacted in the future for opportunities to participate in additional research.

The majority of women are introduced to the cohort and provided with information during their pregnancy booking appointment with their midwives (approximately 8–10 weeks of gestation). In some cases, maternity support workers who see women for separate antenatal appointments before the booking visit may also consent. The EPR system is programmed to remind practitioners to seek consent during encounters throughout maternity care, as shown in Figure 1. This provides a flexible and inclusive process for both women and practitioners.

Beyond routine clinical encounters, cohorts are promoted using posters and participant information leaflets, which are available in relevant areas, such as GP surgeries, community midwife clinics, Children's Centres, religious settings, and maternity units. Regular community events are also held by sites to raise the profile of the cohort and reach a wider community.

Translation

Translated materials have been made available in the ten most common community languages across the BaBi network to enable women to access information in an appropriate format. Where languages either do not have a written form or very few people read the written form, audio recordings and video summaries of the materials are available. All translated, audio, and video versions are freely available on the central and local BaBi websites. Hard copies are available from the local BaBi research team for those who do not have access to the Internet.

Women with language needs are offered interpreting services as standard care throughout their pregnancies. Therefore, women who need this support should have an interpreter with them during routine appointments who will be able to ask questions about taking part on behalf of the healthcare practitioner.

Routine data sources

A broad range of routine data on mothers and children are included as part of the recruitment process. These include (but are not limited to) data from health records, education, welfare, and social care sources. Figure 2 shows a diagram of examples of the data sources included in the participant information leaflet.

Figure 2. Routine data sources that can be linked at each BaBi site (General Practitioner shortened to GP, National Health Service shortened to NHS).

Data management and use

Data sharing agreements are established with the relevant data custodians for each data source of interest at each participating site. Data sharing agreements detail the method of secure transfer of data and the frequency of data updates to be shared. Each agreement is bespoke to the needs of each data source. The common principles of the method are as follows.

•   A list of consented participants’ study ID numbers will be combined with personal identifiers such as name, address, date of birth, and/or NHS number for each participating site. This enables data linkage and record matching. This list of identifiers for consented participants will be shared with the data provider via the secure transfer method previously agreed upon between the data provider and each participating site (as specified in the data sharing agreement).

•   A new version of this list will be created at the time of each linkage attempt to ensure that any participant who has withdrawn is excluded.

•   Only the unique cohort research study ID will be retained by the data provider for future linkage. The linked data will then be sent by the data provider using the agreed secure data transfer method (stipulated within the data sharing agreement).

•   Where feasible and appropriate, OpenPseudonymiser is used to create a shared pseudonymous key for data linkage and matching purposes. OpenPseudonymiser is a free to access tool created by the University of Nottingham that replaces an identifiable variable (such as the NHS number) with a non-identifiable key. It is useful in data linkage because it negates the need for identifiable data to be shared with data providers. Instead, each party uses the tool to create a shared list of non-identifiable keys for the identifiable variable, such as a look up file. This process is only feasible when each participating site and the data provider have a common identifier (e.g., NHS number) and both agree to use OpenPeudonymiser software as part of the data linkage process. This will be explored with each data provider and stated within the data-sharing agreement.

The meta-cohort

Each site is asked to contribute pseudonymised extracts of linked data to the BaBi Coordinating Centre as part of the BaBi meta-cohort. In addition to enabling national generalisability, this meta-cohort will provide larger samples with greater statistical power. At the time of writing, processes to harmonise the data have started, using principles that are agreed across sites, to develop a minimum dataset of key demographic and core metrics. Given the volume of potential data items, we are using a staged approach, beginning with the identification and harmonisation of demographic and key pregnancy outcome data available at each site, while establishing the process for a feasible common model. Over time (and with each new data request), the dataset will increase in size. Data items/outputs will be stored in a cloud based secure data environment and openly available upon request to the BaBi Coordinating Centre.

Management and governance

Each BaBi site is the data controller for the local BaBi, which means that it is responsible for the management and governance of the data collected. Each site is encouraged to establish an appropriate local partnership (or steering) group to provide oversight and support priority setting, data linkage, and use of the linked data. The data controller of the BaBi meta-cohort is the BaBi Coordinating Centre (hosted at Bradford Teaching Hospitals NHS Foundation Trust).

The BaBi Coordinating Centre manages ethical and Health Research Authority (HRA) approval, site setup, initiation, and monitoring. It is also responsible for coordinating network level data requests and expressions of interest for collaborations. In addition to these operational tasks, the Coordinating Centre support a number of ‘Communities of Practice’ (CoP). In these, groups of people with common roles and interests are able to share knowledge across the network, build intra-network relationships, and provide peer support. CoPs include groups for Principal Investigators (to discuss research priorities and site governance), Research Midwives (to support recruitment), Data Operations, and Communications and Engagement. Each CoP is facilitated by a member of the Coordinating Centre team through regular online meetings. Where appropriate, team members from potential new sites are invited to join the relevant CoP to gain a more informal understanding of how sites operate.

Patient and Public Involvement and Engagement (PPIE)

Inspired by the Born in Bradford approach, co-production is at the heart of the BaBi network. The initial study design and development of documents and materials were undertaken in collaboration with community and participant groups. Involvement shaped the way consent was described, the use of example research questions in participant materials, and operational processes. A participant facing animation that complements the participant information sheet was co-produced with community members, who co-designed the content and appearance of the animation and the images and script used throughout. Members of the community are also involved in the planning for how the data are used, and the prioritisation of research questions. As research questions are answered, community members will be involved in designing the dissemination plans to ensure that findings, recommendations, and impacts are effectively shared. Each BaBi site is encouraged and supported by the BaBi Coordinating Centre to establish or access local PPIE groups to facilitate PPIE and coproduction at the site level.

Ethical approval

The protocol for BaBi was given favourable opinion by the Bradford Leeds NHS Research Ethics Committee (reference: 17/YH/0202, 3^rd August 2017) and the Health Research Authority (reference: IRAS 226266, 4^th August 2017). Research governance approval and Sponsorship was provided by Bradford Teaching Hospitals NHS Foundation Trust (reference: BTHfT 2173, 27^th November 2018).

Early site initiation and recruitment findings

Since the launch of the first site in Bradford in 2019, the BaBi network now has 13 active sites. Table 1 provides summary information about the sites, including when recruitment commenced, the number of births per year, and the number of women and babies recruited as of January 2025.

Recruitment targets for BaBi sites start at 10% of the local maternity population at year 1 of launch, working towards 60% in year 5. At the time of writing, more than 62,000 participants have been recruited, with approximately 1500 new (maternal) participants recruited across the network each month. Based on current recruitment rates, it is estimated that by 2028, there will be more than 30,000 participants in the cohort at the first BaBi site (Bradford) alone, and between 6000 and 12,000 participants at each of the other sites, depending on when recruitment started. We have trained over 1,500 clinical staff members to obtain informed consent for the cohort from the women they care for across the network. This has increased research capacity across all sites and, in some cases, has enabled the introduction of research midwife roles at sites for the first time.

Sites are asked to capture any impact achieved onto a central document, which is an adapted version of the VICTOR tool¹⁵.