I agree, yes, a super medicine and "option in the menu" for those who like it so that it is impossible to get rid of them if they have grown together with the ovaries.
I would generally like the ability to get pregnant even when pregnant. Then each "intercourse" with a new insect would be extremely pleasant.
For example, you can make a parasite that, living in the ovaries, allows you to experience this.
Or I just need to get one parasite in the uterus, which would allow me to get pregnant while pregnant.
And in order not to work through hyper pregnant at the initial stages, you could make something like a queue. In which only the first embryo would develop.
When it was born, the next one would begin development and so on until the heroine gives birth to all the embryos.
True, this option would not work for parasites/small insects.
But I studied a similar scenario when I wrote code for "pregnancy system" (see for code -> thread "List of games with pregnancy mods" on f95)