Am 18 weeks pg and have managed (without trying, have just got smaller appetite since about week 4 and, most importantly, lost my sweet tooth!) to lose a pound from my booking in weight - before that, I lost about 7 pounds (partly before I knew I was pg and partly due to sickness).
Surely this is a good thing? Diet still varied, eating healthily (most of the time) but managing (for now) to stay on top of weight gain. Not sure what would be normal for now, anyway, but fairly sure with DD, I was eating almost anything in sight by this stage!
Am sure MW etc would say not to try to lose weight, but for the first time ever, I'm not trying!! (BMI is over 35 BTW)