Gravid
/ˈɡrævɪd/
Definition 1 of 2
Pro Tip 1/3Biological Context
Used specifically for pregnant animals or insects, not just humans. 
The veterinarian confirmed that the turtle was gravid.
Pro Tip 2/3Scientific Tone
Sounds more scientific or technical than 'pregnant'. Use it in formal or biological contexts. 
Researchers studied the behavior of gravid zebras in the wild.
Pro Tip 3/3Not Anthropomorphic
Avoid for describing humans except in medical or zoological terms, where it's more acceptable. 
The paper discussed the health risks for gravid women.