Statistics on Women's Smoking Status at Time of Delivery: England, Q2 2025/26

In quarter 2 of 2025-2026 the percentage of maternities with an unknown smoking status was 7.3%. 

The following 6 Sub-ICBs recorded 20% or more of their maternities with an unknown smoking status:

• NHS North East and North Cumbria ICB - 01H (51.0%)
• NHS Somerset ICB - 11X (36.8%)
• NHS Dorset ICB - 11J (26.5%)
• NHS Bath and North East Somerset, Swindon and Wiltshire ICB - 92G (25.2%)
• NHS Buckinghamshire, Oxfordshire and Berkshire West ICB - 15A (23.5%)
• NHS North East London ICB - A3A8R (21.8%)

During the period of dual reporting (2022-23 to 2024-25), the percentage of unknowns from MSDS was consistently higher than the percentage of unknowns derived from SATOD v1. There is still a relatively high percentage of unknowns in SATOD v2 since the data source was changed to MSDS. There are plans to work with Trusts that are consistently reporting high volumes of unknowns which should help improve reporting in future.

While guidance is in place on how to submit smoking statuses in MSDS, this has not previously focused on the need to record only one consistent smoking status within +/- 3 days of the labour onset date. Some SATOD v2 maternities are recorded as having an unknown smoking status due to conflicting smoking status information being recorded within the +/- 3 days of the labour onset date, e.g. both smoker and non-smoker recorded.

Guidance on submitting smoking status data to MSDS has been published, which sets out which clinical codes to submit for smoking status (as listed in Appendix A) and which MSDS tables to record this information in. As well as reducing the number of SATOD v2 maternities with conflicting smoking status information being recorded, this enhanced guidance should support further reductions in the number of maternities with an unknown smoking status by helping reduce the number of maternities where no smoking status at all is recorded.

This diagram sets out how smoker and non-smoker codes recorded within MSDS are used to allocate a SATOD v2 smoking status:

In quarter 2 of 2025-2026, the following trusts failed data quality checks and therefore their data is not included in the months stated in the table below. Details of the data quality metrics can be found in the Maternity Services Monthly Publication metadata, in the 'CQIMDQ Measures Construction' tab. These are the same data quality metrics used for the CQIMSmokingDelivery measure. The relevant data quality metrics are CQIMDQ02, CQIMDQ06 and CQIMDQ07.