The pregnancy was creating unexpected problems, but nothing major that the outposts weren't ready to handle.
The baby carried the Great Old One's species' genes, so he or she demanded unfathomable quantities of nutrients to grow healthy without sucking Liiza dry.
That was easy enough to fix due to the many checkpoints Khan's forces had placed alongside the route to the Nak's home world. The special ship also needed to refuel often, so Khan only had to increase the number of breaks to restock supplies, too.
That slowed down the trip. The initial estimate would have seen Khan reaching the spherical arrangement of asteroids in little over seven months, but forsaking that timeline had been unavoidable. Liiza and their baby were the priority, and Khan didn't mind delaying his mission by a few weeks.
Also, the delay would have happened anyway due to the Niqols' interference. Musa's interception had ended up being the first of many encounters that forced Khan to take action directly.
