The head of the World Health Organisation (WHO) has criticised the US Supreme Court decision to overturn Roe v Wade, calling the decision to no longer recognise a constitutional right to abortion “a setback” that would ultimately cost lives.

WHO director-general Tedros Adhanom Ghebreyesus said during a media briefing that decades of scientific data proved that access to safe and legal abortion saved lives.

“The evidence is irrefutable,” Dr Tedros said.

“Restricting (abortion) drives women and girls toward unsafe abortions resulting in complications, even death.”

He said safe abortion should be understood as health care and warned that limiting its access would disproportionately hit women from the poorest and most marginalised communities.

“We hadn’t really expected this from the US,” Dr Tedros said, adding that he was concerned the Supreme Court’s decision was a move “backwards”.

In recent years, the US had supported numerous maternal healthcare programmes in developing countries, including access to reproductive healthcare.

“We had really hoped the US would lead on this issue,” Dr Tedros said.

WHO’s chief scientist, Dr Soumya Swaminathan, said the UN health agency’s position on abortion was based on decades of data from numerous countries.

“I know from my own experience, working in India, that having access to safe abortion is a life-saving measure,” Dr Swaminathan said.

She said denying a woman access to abortion was “like denying someone a life-saving drug”.

She said bans on abortion would do little to reduce the number of procedures, while people who underwent unsafe abortions were at risk of developing fatal blood infections.

“What these bans do … is it drives women into the hands of people who are there to exploit the situation, performing unsafe abortion and very often resulting in a huge amount of damage to their health and sometimes death,” Dr Swaminathan said.

In recent years, the trend among countries had been to increase access to abortion, including regions where there was staunch opposition, including Latin America, she said.

“It’s unfortunate to see some countries going backward,” Dr Swaminathan said, citing the US decision.

WHO chief Dr Tedros said he feared many other countries might not understand the implications of the US Supreme Court ruling and could take similar measures to restrict abortions.

“The global impact is also a concern,” he said.

“This is about the life of mother,” he added.

“If safe abortion is illegal, then women will definitely resort to unsafe ways of doing it. And that means it could cost them their lives.”