Rh+Negative+Mother

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** CCRMC OBGYN **** Prenatal Guideline ** Consultation available 24 hours per day from OB on-call at 925-370-5608 or via page/amion, via inbasket to OB dept member or by calling Perinatologist at 510-444-0790 during the day and 510-204-1572 after hours. Consultation appointments or transfer of care to more experienced prenatal clinician available at major clinics sites—see consultation guidelines for more information.

Rh neg mothers are at risk of developing antibodies to the D antigen of the Rh group of antigens if exposed to Rh positive blood from the fetus. These prenatal patients are identified by an **Rh negative blood type** and a **negative antibody screen** in the prenatal lab panel. The goal is to prevent sensitization to the Rh antigen to lessen harm to future pregnancies. Most common sensitization occurs from carrying a pregnancy with an Rh positive fetus from an Rh positive father and sensitization can be prevented by administering Rh antibodies (Rhogam) IM preferably within 72hrs and up to 2 wks after exposure to the fetal blood. If the mother is Rh neg, tell her about Rhogam and __**PUT IT ON THE PROBLEM LIST as Rh Negative antepartum**__ to help to remind all to give Rhogam. A repeat antibody screen is always drawn just prior to giving Rhogam. An order set links the Rhogam order with the lab order. The patient will need to go to the lab and have an antibody screen drawn before the Rhogam will be released.

__Dose:__
 * 50 mcg IM if <12wks
 * 300 mcg IM if >12 wks

Sensitization can occur with delivery, during the latter portion of the pregnancy, or from other events which cause feto-maternal bleeding such as amniocentesis, CVS, cordocentesis, version, trauma, miscarriage/ ectopic/ elective abortion/molar pregnancy, antenatal hemorrhage. __To prevent sensitization:__

-if rosette test negative, a standard dose of Rhogam will do -if rosette positive, more Rhogan is necessary (dose calculated with a Kleihauer Betke test quantitating the fetomat bleed)
 * **Give Rhogam routinely at 28wks**
 * Give Rhogam for any antenatal vaginal bleeding, abdominal trauma, early pregancy loss (mole, EAB, SAB, ectopic) or invasive procedures detailed above.
 * Give Rhogam within 3 days postpartum if cord blood shows baby to be RH positive
 * Give more than standard dose Rhogam in cases of more significant feto-maternal bleeding. This situation is confirmed with a rosette test on maternal blood.

Rh negative mothers who have already been sensitized have a **positive antibody screen** to the D allele of the Rh antigen on the prenatal lab panel--in this case see Isoimmunization guideline. Rhogam is no longer useful.


 * Note that recent administration of Rhogam is probably the most common reason for a positive D antibody on screening labs--get a good history of any potential clinical encounters where the patient may have received Rhogam--this patient would not be at risk of hemolysis and would still require Rhogam later during this pregnancy*****