pregnancy in the work force ,my Daughter-In-Law is having issues at work with her bosses

She is having complication with her pregnancy. her Doctor has sent them three excuses and they are ignoring the orders he has given them .She has copies of these excuses . They wrote her up for going to the doctor with having pain and spotting,,, And he recently diagnosed her with low amniotic fluid and put her on bed rest for a week to allow the fluid to build back up ,He allowed her to go back to work but she is to have light duty not allowed lift, but they are still ignoring his orders and the other workers are harassing her on the job due to this,namely the bosses son he gets away without wearing scrubs it is required attire for this job and others are suppose to wear hair nets and are getting away with out wearing them , and she gets wrote up for Pregnancy complications this is unfair practice ..what are her rights and what can she do ?