It is a discriminatory practice, directly or indirectly... in the course of employment, to differentiate adversely in relation to an employee, on a prohibited ground of discrimination. (politics.stackexchange.com)
Under human rights law, pregnancy is a protected ground of discrimination under sex / gender. (toronto-employmentlawyer.com)
The words «on a prohibited ground of discrimination» add nothing more than a casual link between the protected classes and the differentiation or effects. (ccdonline.ca)