There is an increase in metabolism during pregnancy as well so if you are just eating a little bit less than normal it can result in an overall weight loss.

I was 10kg less with my first pregnancy and ended up 8kg less than my pre-pregnant weight with DS as well. This time I have only gained (roughly) 5kg so I will be less than pre-pregnant after birth too.

As long as you are getting the normal movements and bump is measuring to size then try not to worry - it is a great side effect that many are jealous of. Usually, it just means we had a little more *flesh* on our bones to start with than our leaner friends