Abdomen too small 👶🏻

I went for my 35 week check up and baby is growing well except for his Abdomen, it measures about 2 weeks too small and under the scale. He weighs about 2.345 kgs so 5 lbs 16 oz. The dr said the blood flow from the cord is normal. 

Do any of you have a similar issue, if so please advise on what i can do because i have increased my food portions but its still not enough?