The Zika virus epidemic has doubled requests for abortions in affected countries, a study has revealed.

The virus - spread by mosquitos - is thought to cause severe birth defects if a woman is infected during pregnancy.

Examinations have confirmed the virus destroys brain tissue and has led to some babies being born with smaller heads.

There is currently no treatment for it and official advice to women is to not get pregnant in Zika-infected zones.

But millions in Latin America - where access to birth control is limited - have undergone abortions as they do not want to have a sick baby.

Many of these are thought to be "back-street" abortions as the procedure is illegal in such countries.

Or they have turned to help groups such as Women on Web who specialise in getting abortion pills to women in countries with restrictions via drone, speedboat or other methods.

Dr. Thomas Gellhaus, president of the American Congress of Obstetricians and Gynecologists, said more must be done to help these women.

"All women must have the legal right to abortion, unconstrained by harassment, unavailability of care, procedure bans, or other legislative or regulatory barriers.

"The Zika crisis makes it impossible to ignore that women around the world do not have access to this basic health care need."