Scorching heatwaves fueled by global warming are increasing the risk of dangerous complications during pregnancies across the world, a report warned this week.

In 222 out of the 247 countries and territories studied, "climate change at least doubled the average annual number of pregnancy heat-risk days experienced during the past five years", the report said.

Extreme heat is linked to a host of maternal health problems and Australia is already experiencing more days hot enough to pose pregnancy risks.