The oath made by the Styx River cannot be violated; the moment it is established, it entwines itself around the swearer. Before this, neither Hecate, who made the request, nor Leto thought that the thing related to 'Moon' was an item. Their judgment was actually correct, it indeed was an item, yet this item had not yet been born. It was one with its owner, which meant that Leto had to face a reality, her oath might become even more difficult to fulfill.
This was not even an issue that could be resolved by sending the child away, for Artemis is a deity, and to the world, she belonged to no one. No god could fulfill an oath with the 'ownership' of another deity, after all, in the divine hierarchy established by Chaos, even parents and children are by no means subordinates to one another.
"Mother Goddess, what's wrong?"
