My friend has just announced she is pregnant again and may have Rh incompatibiliy. She may be OK as her first pregnancy did not sensitize either her or the baby and the hospital were very careful with her and the placenta/umbilical cord at the birth. However, she does not want Rhogam human plasma derived serum and wondered how effective photothereapy was. Also, she has heard that certain types of diet and supplements can change your rh status. Is is actually possible? Has there been any research into this? We found some diet information on this site:rh but do not know how worthy the information is.