09/27/2013 12:49 EDT | Updated 11/27/2013 05:12 EST

Pregnant teachers face contract discrimination, says union

In one case at Margaret Jenkins Elementary School, one class had six different teachers last year. Principal Barb Hardy says the situation was hard on the students.

"After about teacher four or five, the children were saying, 'Why don't my teachers like me?  I don't want to come to school anymore.'  And they found it difficult to understand why this was happening."

The district now requires substitute teachers to agree they will be available for at least half the contract.