[Note 2] In 2022, Hywel Dda health board did not provide any data for smoking at birth and Cwm Taf Morgannwg had an unusually high percentage of missing data.
[Nodyn 2] Yn 2022, ni wnaeth bwrdd iechyd Hywel Dda ddarparu unrhyw ddata ar gyfer smygu ar adeg yr enedigaeth ac roedd gan Cwm Taf Morgannwg ganran anarferol o uchel o ddata coll.