I am a work from home mum and I am thankful that I have this option. However, do you think this poses a disadvantage to my career?

Depends on so many factors -- what industry you are working in, the position you hold and how flexible your employers are. I came from a civil service background and I have not heard of anyone doing this. But my friends in the media industry (writing, publishing), I've heard of such instances. Some of them in trading often work from home too. In Sweden, where I am currently based, it is very common for moms and dad to work remotely with no disadvantages to their career progress. I reckon, if you work hard and meet your goals as well as the company's -- it shouldn't pose a problem, especially if they were the ones who are okay with you working from home.

It would depending on the type of career you're looking at. Most companies now facilitate work from home mothers and can accommodate you; however for some senior positions this just is not the case.