Most of the civilian population of Ukraine is taken up in defending the homeland, when would they have TIME for procreation? Besides, most of the maternity hospitals have been destroyed, so there is no place to deliver the babies anyway. (I know, both of these claims are entirely specious, but absurdities crop up everywhere in regards to this conflict.)
For example, why does the battle even continue? Both sides are like two weary and punch-drunk boxers in the middle of the ring, leaning on each other, throwing ineffectual punches, but neither one wants to call it quits.
Because one side believes the other should not exist as a free and independent country.