The Maternity Indicators Data Set captures data relating to the woman at initial assessment and to mother and baby (or babies) for all births. This relates to initial assessment and birth activity undertaken in Wales only. Each Health Board must make available data in relation to the initial assessments and/or birth events which they managed. For example, if they only carried out the initial assessment the Health Board would only be required to provide the initial assessment data. This is further detailed in the technical specification (see ‘return submission details’). Where the initial assessment and birth events take place in different Health Boards, data will be linked nationally by the NHS Wales Informatics Service. Velindre NHS Trust are excluded from this requirement, as they do not provide any maternity services. Monthly activity data must include only initial assessment and birth activity that took place in the previous month.