I've made a few baby quilts so far (well, I'm starting only my 3rd....).
The first was a lavender print with dark purple diamonds as the feature; no cream or white (but wasn't pieced blocks exactly, either...).
The next was a baby lone star, with the star in bright pinks, the surrounding circle in dark blue & white, and the background triangles in a white fabric printed with multi-colored ribbons (which picked up the blue and pinks).
The current one is butterflies in squares (panel/printed fabric) that will be framed in dark purple batik and with light purple/lavender batik as the border/main background color. The center square will be the same ribbon fabric (I think?) with an applique initial out of the darker purple.
So.....all that to say, I tend to use whatever background color makes sense for the quilt/other fabrics. I might would use a pale pink or a pale blue instead of a cream/white, if I knew the gender already, and if that worked with the other fabrics. But, I just send along color catchers and washing instructions, and don't fret too much over "will this color get dingy" as I assume they'll wash it.
FWIW, I have a couch quilt with cream, and it's the first one I made/finished and only in a very few places is it showing the dinginess of being in use for all this time (it is washed regularly). Another has white but is only 2 yrs old, and again, no sign of staying dirty. Not that we have babies crawling around spitting up on them, but kids, dogs, etc.....in other words, the good quilting cottons you use will wash well and not get that same dingy as a white t-shirt or socks or whatever, if that makes sense.