Quite opposite, if Russia drafted women, there would be a baby boom in Russia.
Based on data from US military (professionals, not draftees), female service members are very likely to get pregnant, just before combat deployment.
So drafting women is a double win, it increases number of soldiers and increases fertility.
So when they get pregnant at the last moment their training is wasted and a soldier is lost. And if they don't get pregnant with the right timing, they get fed into a meat grinder at the front? It seems suboptimal.
And if the survival of your culture depends on forcing women to breed on fear of death, better if it doesn't.