Personally I don't like anything that encourages you to eat "meal replacement" as once you stop them you tend to put the weight back on plus more. You don't really know what is in these shake things either especially if you are TTC you want to putting the least amount of rubbish, preservatives etc into your body as possible.

I would go with a more whole food approach that you can stick to throughout your pregnancy. Try to eat foods as close to their natural state as possible eg. lots of fuit and veg etc.