At dining table scene from Eternals (2021), Kingo asks Gilgamesh a question about Thena:
Kingo: Should she be drinking?
Gilgamesh: No, hers is non-alcoholic. For kids.
Is Thena pregnant in this scene?
Thena has a mental illness that makes her violent and uncontrollable. Kingo's concern is that alcohol may exacerbate her condition and cause her to lose control if she gets drunk.
Gilgamesh reassures him that she's drinking a non-alcoholic drink (one suitable for children) that won't cause her to become intoxicated.
You may also wish to note that none of the MCU 'Eternals' appear to be fertile in the film. Despite being in long-term relationships with each other over thousands of years (and various humans for shorter periods of time) they don't have any confirmed children of their own.
Salma Hayek explained in an interview that the Eternals can't have children.
"I'm an alien. I can't have kids. However, my character used to be a man in the comics, now it's a woman. So instead of just changing the gender, I proposed to really bring something that is very specific to womanhood,"