If you have 2 years continuous service you must be provided with a written statement of the reason for your dismissal, if you request this from the Employer.
Your employer must respond within 14 days of any request being made by an employee. A refusal or failure to comply with this request means that you may take the matter to an Employment Tribunal. You may receive compensation if your employer does not respond.
A pregnant woman does not need any continuous service, she has the right to a written reason for her dismissal without a qualifying period. (Any dismissal connected with pregnancy or maternity leave is automatically unfair, and could also be Sex Discrimination.)