Two out of seven health boards in Wales do not provide sanitary products to patients, an investigation has found.
Freedom of Information requests by the British Medical Association (BMA) show Powys Teaching Health Board is the only one which provides sanitary products for free to any inpatient.
Four Welsh health boards provide free sanitary products to selected patients.
The Welsh Government has said local authorities will get funding to tackle period poverty in deprived areas.
The results also show some health boards have sanitary products available to buy at all sites, while others only make them available to buy at certain times.
Dr Philip Banfield, immediate past chair of the BMA's Welsh council, said the results showed period poverty still existed in Wales.
"Reliable access to female sanitary products is essential for the health and dignity of patients in hospital, yet these alarming figures confirm our worry that they are not always readily available for patients who require them as part of their basic human needs," he said.
"Having sanitary products easily available to all inpatients and easily accessible by hospital staff across all health boards in Wales would save both patients and staff from uncomfortable and hugely embarrassing situations. Basic products cost as little as 1p each for a hospital to provide."
Across the rest of the UK, two out of five hospital trusts and health boards do not give sanitary products to patients who need them, or only in emergencies.
The Welsh Government has said that local authorities in deprived areas will receive £440,000 over the next two years towards tackling period poverty.