It depends on the fabric. Mostly, my experience positive, using methods others above described. (Front loading machine, no-heat, gentle/hand wash cycle, mesh bag, gentle detergent, flat or hang dry,
Even with these precautions, I've had rayon shrink in length. Mr Maximal is even more careful about laundry than I am, and hangs everything except bed linens, but we have different opinions wrt the washer settings "cold" and "no heat."
I love nice pajamas, and prefer they be machine washable. Seems the only way to get that these days is to have them made. Are there user reviews of this set available? They're very pretty!