Baby measuring small 😞

Hey ladies just looking for some suggestions/advice I went for my 28 week growth scan yesterday and the consultant said baby is overall measuring small and I have to go back in 2 weeks to re scan.. when I got home I checked my notes and turns out she's only 1lb.8oz.. so my question is is there anything I can eat/drink to help her grow / fatten her up abit.. this is my 4th baby and all my others have been below 7lb but always on target on their charts.. any advice would be appreciated thank you!!!