why should you care? the employer is obliged to supply the same or similar position for you by law.
it is ridiculous to sign a contract that you can't get pregnant within one year or two. It is even illegal for the employer to ask those kind of questions such as your age, your religion, if you have any kids, do you have any family plan, etc. If there is a question as this, you are sure have a case to protect yourself.
This is CANADA! Any kinds of discrimination is not allowed, at least in paper!