• Heat wave
• Neural Tube Defects
• Birth defects
• Extreme climate
• Congenital malformation

The pattern of extreme climate events has changed considerably over the past decades.¹ The frequency of extreme heat conditions has steadily increased during the second half of the 20^th century and it is predicted that there will be a surge in the incidence and intensity of such events in the future.¹ At the same time, the rapid urbanisation which has occurred worldwide over the last 50 years is predicted to continue,² leading to an increase in the number of people vulnerable to excessive heat. The combination of the projected increase in the incidence and intensity of such conditions and the growing number of people vulnerable to these conditions has given rise to major public health concerns.

Pregnant women are among the subpopulations most vulnerable to the effects of extreme heat conditions.³ Increased fat deposition and a decreased body surface area to body mass ratio due to weight gain during pregnancy could reduce a woman's ability to lose heat to the environment.^{3 4} There is also an increase in internal heat production due to fetal growth and metabolism and to an interaction between maternal body mass and physical activity.^{3 4} These changes limit the ability of pregnant women to alleviate heat stress which is a function of internal heat production; …