It is not jaundice at 3 months that needs to be checked, though by
three months, most babies will not be jaundiced to the point of it
being easily noticeable.  A simple question to the mother will clarify
if the jaundice is due to liver disease.  "When your baby pees, is the
urine clear as water?".  If yes, this will eliminate liver disease 90%
of the time.  However, to be sure, the urine can be checked with a
dipstick that detects bilirubin.  If this is negative, no problem.
Also, a baby with biliary hypoplasia will usually have a big liver and
spleen, with atresia, always.

Jack Newman, MD, FRCPC