MANZI Women's 2 Pairs Plus Size Control Top Ultra-Soft Tights

Would these be suitable as maternity tights?

I'm 5'6, and 16 to 18 in trousers. I'm debating getting the xl will it fit?

Im a size 16 but im small im 4 foot 8, do you think a XL would fit?

I'm generally a size 18 and 5ft 7 what is the best L or XL?? The reviews are not helpful..