If you give wormer with a very particular dose you don't need to do an egg withdrawal
Note: according to the particular post linked above, pertaining to dosage that doesn't require egg withdrawal, it is only effective for large roundworms and cecal worms, not capillary worms. The post goes on to state that treatment of capillary worms requires a larger dose and egg withdrawal period should be observed (**At the discretion of the person consuming the eggs, of course. As you can see, there are those who don't follow withdrawal recommendations and they haven't experienced any known negative effects, so it's really up to the comfortability of the egg-eater...)