for heavily pregnant women i use neither lafuma or couch... i prop them on the sofa, lots of cuchions, put their legs and feet up on cushions on the leg rest thingie (puff/poof in my day... lol).
i then have to sit crossed legged, as comfy as i can be... i reckon their comfort is in greater need than mine.
i've had heavy pregnant women that the lafuma was a no-no, due to being tipped back and weight then being on vena cavae...
try it, see if they like it... but have an alternative if they dont.