“Mission Control? This is the Commander of [redacted] speaking. It is with... great apprehension that I must announce we’ll very soon be accepting new crewmates onboard the spacecraft. We don’t know much about what the alien that attacked one of our Flight Engineers planted within his body, but in the three following weeks it has expanded... *massively.*
While the rapidly growing Flight Engineer has continued his duties in the meantime, the activity and sheer size of his abdomen has begun to hamper his ability to work and is beginning to worry the other crew members. We’re not sure how much longer his belly will be able to handle whatever it is that’s inside it, but we will continue to monitor the situation
The scientists aboard the spacecraft are working overtime to find out more about this strange alien pregnancy, though it's hard to really find data on it anywhere. The alien that breached the ship and filled up the Flight Engineer's body with... 'something' wasn't of any well known species, and the little information the scientists had of it actually mentioned that these aliens do not mate with each other. Asexual reproduction was a prediction, but an unreliable one, considering they were very complex beings, but that was the leading theory on this species' reproduction method.
Of course, now they have a new theory as to how these aliens reproduce, or at least an additional way to do it, the method being, well, impregnating beings of other, completely different species and letting the amorphous slimy spheroids grow and mature inside the body of the 'vessel'.
It was clear that the Flight Engineer was pregnant, as he was exhibiting normal human pregnancy behaviors, though a lot of hormonal and overall physiological aspects were greatly amplified compared to usual pregnancy levels. It made sense, as the man's belly was gigantic, bigger than his whole body after only three weeks, meaning he needed more nutrients and hormones than ever to keep those...creatures healthy inside him. Perhaps his soon to be children?...The crew hoped the gestation period was nearing the end as his growth had been out of control, to the point he worried he couldn't handle it and could burst at any moment! Thankfully, his skin was a lot stretchier than he gave it credit for, and that didn't seem like it'd happen now. It was unfortunate that he had to stop working from getting too pregnant, but he really needed that extra rest.
The crew was as helpful as they could be, but after another week, the room where he slept on was becoming dominated by his colossal, shaking, wobbling belly, as the egg-like slimy beings inside squirmed more and more. It was expected for them to be delivered somewhere between 2 weeks and a month's time, though having that timeframe to look forward to didn't exactly inspire the crew. It was only an estimate from the science team with the extra info they collected by analyzing his pregnancy, so it wasn't fully reliable. They worried his belly could become too big and heavy for the ship to handle, since there was still a long time to go, considering his growth rate.
At least he didn't seem as worried himself anymore, the belly rubs from all the crew members secretly made him blush, and he was starting to like the attention...His mind having drifted from thinking he'd burst at any moment, to wondering how huge he could get...