In a scenario where you are losing a significant part of the population to war, it's better that it be men.
in a scenario where your country is on the verge of war, where will those women procreate? I imagine that those who can will leave the country ASAP
Only if you ignore free will. Feels unlikely that women will suddenly abandon monogamy and forced procreation à la the draft is probably very unpopular especially given that women would be a majority. Not that they’re wrong to disagree, but there are more conditions here than the biology of procreation.
The modern answer would be immigration, and that’s gender-agnostic.