Can a female Religious (a nun or sister) be expelled from her order after a hysterectomy? I wanted to ask if a female Religious (ie, a nun or sister) who has become sick and had a hysterectomy, can she be expelled and sent home before her perpetual vows and under which grounds?
Can a Religious (a nun) be expelled from her order after a hysterectomy?

The short answer is no.

No religious would be expelled from their Religious Order simple because they got sick and doctors had to perform an hysterectomy. If she developed cancer and the hysterectomy was deemed necessary, there would be no sin in having an hysterectomy. The surgery could  be necessary because cancer is a death sentence, if left untreated.

That said I have known religious to be sent home to their families in order to recuperate from surgery and illness, but returned after a time of convalescence and once their health had improved.

Not at all the same as a hysterectomy, but the amputation of a limb for example would not be a cause for expulsion from a Religious Order.

We see in the life of Brother Anthony Kowalczyk, OMI suffered a grievous accident that made it necessary for the doctor to amputate one of his hands while still a simply professed brother. He eventually went on to become a solemnly professed Oblate of Mary Immaculate.

Caveat:

Most Religious Orders ask that postulants, novices and simple vowed Religious must generally have good health in order to take perpetual vows. Having an hysterectomy in itself is not a reason for permission not to be granted the grace to pronounce solemn vows, but if the cause is of the hysterectomy was simply a bandaid in one’s health (terminal cancer) in order to prolong one’s life, the Religious in question could be asked to leave due to general poor health. Some communities, nevertheless, allow such persons to remain in the community as oblates or internal oblates.