Mothers and babies are uniquely and safely identified in MSDSv1.5 using the pseudonymised data items, MSDS_ID_Mother and MSDS_ID_Baby. These items are derived from a combination of identifiable data items, such NHS number, date of birth, postcode and gender to search a patient index and apply an existing ID to matching patients already present in the index or allocate a new ID for new patients. The index is common to both MSDS and the Community Services Dataset (CSDS), allowing linkage to track patients accessing both services.
MSDSv2.0 uses the new Master Person Service (MPS), to allocate similar pseudonymised items, PERSON_ID_Mother and PERSON_ID_Baby. The MPS is an enhanced patient-matching algorithm that increases the number of linkable records where incomplete records have been submitted. It is intended that MPS is commonly used across a large number of datasets, facilitating simpler data linkage.
The two methodologies are not compatible, however the new PERSON_IDs created by the MPS will be retrospectively applied to MSDSv1.5 data, making it possible to track mothers who have babies over the lifespan of both datasets.
Unique Pregnancy ID
Unique Pregnancy ID is used to identify events such as antenatal bookings, screening tests, births and clinical interventions across a single pregnancy. In MSDSv1.5, this field (called UniquePregID) is derived using a combination of MSDS_ID_Mother and Estimated Date of Delivery.
In MSDSv2.0, the equivalent field (called UniqPregID) is created differently. In the new dataset, providers are able to submit their own values (in the field PregnancyID) and these are also used in the derivation.
In common with patient identifiers, these are not compatible across the two datasets, but the new version of the field will again be retrospectively applied to the previous dataset enabling events to be linked for pregnancies that begin in MSDSv1.5 and conclude in MSDSv2.0