Mae GIG Cymru yn trin mwy o gleifion sy'n ddifrifol wael, ac sydd â lefelau uwch o ddibyniaeth, sy'n golygu bod angen iddynt dreulio mwy o amser yn yr ysbyty. Mae hyn yn cael effaith ar lif cleifion drwy'r system gofal iechyd, gan nad oes modd rhyddhau pobl o'r ysbyty mor gyflym ag ar adegau eraill o'r flwyddyn, ac o ganlyniad, mae llai o welyau ar gael i gleifion.
NHS Wales is treating more acutely ill patients, who have higher levels of dependency, which means they need to spend more time in hospital. This impacts on patient flow through the healthcare system, as people cannot be discharged from hospital as quickly as they would be at other times of the year and there are consequently fewer beds available for patients to be admitted to.