Organisers opted to start the women’s event at 11:59pm local time (20:59 GMT) on Friday due to the daytime heat in Doha.
However, with temperatures exceeding 32 degrees Celsius (89.6 degrees Fahrenheit) even at night, and humidity levels above 70 percent, 28 of the 68 starters failed to finish the race.
Ahead of the marathon, there were fears the conditions might not be conducive for the race but organisers decided to go ahead as scheduled.
Most of them have been training late into the evenings after arriving in Doha.
“Getting used to this [heat, humidity] is very difficult. We have never experienced this before,” said a group of Ukrainian athletes who had pulled up during training due to the high humidity.
The men’s event will take place on October 5.