Is it obligatory to make up the prayer if it is highly probable, though not certain, that vaginal discharge or menstrual blood exited during it?

If someone doubts whether something has exited from them or not, the default is that their ritual purity (tahara) remains. It is not invalidated by mere doubt, and this applies whether they predominantly suspect something has exited or if both possibilities are equally probable. Indeed, the certainty of purity is not removed except by the certainty of impurity. The proof for this is the saying of the Prophet, peace and blessings be upon him: "He should not leave (his prayer) until he hears a sound or finds a smell." Therefore, there is no obligation to repeat the prayer.