When you look for content involving impregnation, you generally find three distinct categories: (the science of survival), Dynasty Management (the politics of bloodlines), and Narrative/Adult Roleplay (the intimate or fetishistic aspect).
In mature gaming, impregnation is often paired with transformation (changing the character's body or status). This creates a visual progression that makes the gameplay rewarding. Games that feature this usually have strong art direction.
Fantasy literature often uses pregnancy as a transformative experience for characters. For instance, in "Harry Potter," certain magical pregnancies are central to the storyline, showcasing the challenges and uniqueness of such experiences.