NEW DELHI: A latest study revealed that hot and humid conditions driven by climate change could increase cases of stunting in South Asia's children by over three million by 2050.

Researchers found that pregnant women are known to be susceptible to heat stress due to the additional weight and hormonal changes, which make them 'vulnerable' to overheating.

The findings published in the journal Science show that humidity can worsen the impacts of exposure to heat, in part as it prevents pregnant women from cooling down.

The worst times were found to be in very early and very late pregnancy.

The researchers from the University of California, Santa Barbara, US, looked at how exposure to extremely hot, humid conditions during pregnancy can impact children's health in the populous continent.

'Height-for-age', a commonly-used indicator of chronic health status for children aged under five, was analysed. It refers to the ratio of a person's height to what is average for their age.

"At the beginning of pregnancy, the fetus is very vulnerable, while at the end of pregnancy, the mother is more vulnerable," lead author Katie McMahon, a doctoral student, said.