Mortal Coil - S4-E12
Continuity mistake: The shuttle is "parked" in the nebula to get a protomatter sample, and the nebula is visible in all windows. After the shuttle is hit, the camera looks at Tom, and the view in the window is the black of space with stars, rather than the bright nebula.
Suggested correction: It's also possible that it's simply required of Ocampan women to give birth the first time they go through it, and can then experience it again.
Greg Dwyer
Nothing in the dialogue suggest Ocampa's can have additional children. While we can speculate about fictitious species, it's still a plot hole due to writing. Kes states she's going through the "elogium" which is a time of change where her body prepares for fertilization. She then explicit states the "elogium" only occurs once. While the doctor compares it to puberty, the elogium is both sexual maturity and "heat", that is, the time a female is ready for fertilization.
Bishop73
But it doesn't ever state the normalcy of birthing for Ocompans. Perhaps sextuplets is the norm?
Kes frequently used the word "child." If it was normal to give birth to more than one, she would know this and should say "children."
Bishop73
Do not forget that this is all done through the universal translator. For all you know the Ocompan word for child and children is the same so the translator cannot tell the difference.