1) What the most used method of treatment is
not severe = phototherapy
more severe with anemia but bili under preset levels = blood transfusion without exchange
most severe = double volume exchange transfusion.
Intravenous immunoglobulin (IVIG) is widely used as adjunct therapy.
Supportive cardiopulmonary care for any hydrops-related issues.
2) The biggest risks in using that treatment
that the patient will die from the exchange transfusion
3) How soon does the fetus have to be treated?
fetus? oh, if you want to talk about in utero treatment, try the OB board. I'm a baby doctor.
4)Possible complications
Of therapy: That the patient will get an infection, will get a bloodborne illness from the transfusion or will die from the exchange transfusion (less than 0.5% risk of death in the past, near zero in a full-term infant with modern day neonatal care).
Of the disease: Depends on severity - if the baby is hydropic, they could die of cardio-respiratory failure. From high bilirubin itself - a lousy condition called kernicterus that you can look up easily.
5) Patient's worries when informed of the disease
If you mean the patient who has the disease, we see relatively little worry amongst them. Their parents are worried that the patient (their baby) will get an infection, a bloodborne illness or will die from the disease or its theapy. That assumes we've told them of these problems or they've read it on the internet.