My sister is o neg.she had mscariage for her first preg.didn't receive rogam, now she has mscariage again 2nd time 4hrs.ago.is rogam stil efective for her?is there a chance for her to have a healthy baby in the future?how long before she can be preg.again

Probably unrelated: Rhogam is used in rh - patients who may carry an rh + fetus to prevent isoimmunization. It's to prevent antibodies against rh + fetuses and prevent an hydropic fetus (lethal condition). Her miscarriages may be unrelated but you're correct, usually rh - women receive Rhogam within 72 hours of possible exposure to rh + blood (as in miscarriage). Prenatal labs always check for these abnl antibodies.

RH factor: Rhogam is not always given for early miscarriages, though we often will give it at the time of D&C related to pregnancy loss. She should have a type and screen done to see if she has had a reaction to the duffy antibody. In general most women restart ovulating 15-30 days after a miscarriage. If Rhogam is offered this time its ok to get it.