I know with Red Ear Sliders, females sometimes becomes gravid with infertile eggs even without contact with a male. this can pose a potential health problem called "egg binding" where the female can't find a nesting site for her eggs and so they remain and bind inside of her.
For a Red Ear, this is dealt with my creating a nesting site (can be a box with 6-12 inches deep of soil, depending on her size) and letting her spend some time in it each day until she lays.
I don't know if it's the same with muds or not...
1 Red Ear Slider - Terra
1 Cocker Spaniel - Zoey
1 Mudskipper - Pangea
3 Bettas - Mars, Venus & Neptune
20g FW community tank
30g SW tank: porcupine puffer, fiji puffer, clown fish