The Maternity Services Data Set (MSDS) is a patient-level data set that captures key information generated as part of care within maternity service providers at each stage of the maternity care pathway including the antenatal pathway, the birth episode pathway, and the postnatal pathway. The antenatal pathway starts when the pregnant woman has her first antenatal appointment with her maternity provider, at around 10 weeks’ gestation. The MSDS continues to capture information until the date on which the mother ceased to be cared for in maternity services. Information on care prior to the first antenatal booking appointment or following discharge from maternity services is not contained in the MSDS.