United Kingdom, June 24 -- Allison Williams experienced "huge trauma" while giving birth to her son.

The M3GAN actress - who has three-year-old Arlo with fiance Alexander Dreymon - has recalled her "very stressful" time in hospital when she endured 36 hours of labour before needing an emergency caesarean section, and she admitted she hadn't even thought about the possibility of needing surgery.

Speaking on the Not Skinny But Not Fat podcast, Allison said: "From the moment I arrived, pre-epidural, every time I had a contraction... his heart rate would go down."

Asked how she felt in the moment, she added: "Huge trauma. Deeply stressful. I realized in that moment that I hadn't thought about the possibility of having a C-section.

"I hadn...