When it comes to coaching pre & post-natal clients, the cover would depend on what type of class you are teaching and your qualifications.
If you are teaching a specific Pre & Post-natal Fitness Class then you would need to ensure that you have the relevant qualifications or experience to teach Pre & Post-natal Fitness. If your existing qualifications include Pre & Post-natal training then you can start coaching these classes right away.
If it is not a specific Pre & Post-natal class, for example if you are offering a normal Yoga class to pre & post-natal clients, then there is nothing in our policy to stop you from training these clients however you would always need to take steps to ensure you're doing your due care and diligence towards your clients.
If you are ever uncomfortable with training a particular client, you can always ask them to provide a note from their doctor confirming that they are fit to train in your class.