Mild renal pelvic dialation (both kidneys) has been identified for the first time at 27 weeks gestation on my baby boy, measurements range from 4 to 7 mm. I do however have an asymptomatic (not haemolytic and oxygen saturation normal) form of hereditary elliptocytosis, where 30-40% of red blood cells are elliptical. My research suggests that this is carried on the X chromosome and thus I may have passed the condition on to my son - my question is could this perhaps be the cause of this pelvic dilation?