I have the mothercare xtreme pushchair for ds. The car seat clips into the pushchair for babies.
Ds is 16 weeks and the car seat but seems cramped, I was just looking to find out whether it was safe to put him in the pushchair strapped in tightly without the car seat bit (didn't find an answer)
But I found a different website of people going mad saying you should never have a baby in car seat in the pram as it can damage hips and spine 

Might be a stupid question but I'm panicking now!
Is that true? And does anyone know if I can put ds in the normal seat bit if he is strapped in tightly? He holds his head up well.
Tia x