RH Factor
if heterozygous child possible, what should you offer?
amniocentesis to determine if fetus is + or - ; amnio can increase risk of sensitization
what is rhogam?
anti-D immune globulin; started in 1980's; blood product that provides antigen clearance, antigen-blocking and suppression of antibody response
why do babies w/ jaundice need frequent feedings?
b/c bilirubin leaves body in infant's stool
why might you not want to do amniocentesis to determine zygosity?
b/c increases risk of blood exposure/sensitization
how is bilirubin light level determined?
based on hours of life old
what happens in second pregnancy of RH negative mom and RH positive fetus?
can cause erythroblastosis fetalis
when/how do you determine blood type of baby?
cord blood at birth
what happens in hydrops fetalis?
heart failure r/t to fetal anemia/ hemoloytic dz newborns
DAT test and Coombs test tests for baby's that are more at risk of...
hemolytic anemia??
adverse reactions w/ rhogam?
injection site soreness, slight fever less common: allergic rxs, elevated bilirubin, lethargy
what problem occurs if bilirubin levels are too high?
kernicterus - bilirubin crosses blood brain barrier and binds to brain tissue --> permanent neuro damage
if mom is RH negative, and fetus is RH positive, what can happen?
mom's mounts immune response, treats baby's RBC as foreign; not a problem for 1st pregnancy but is problem for subsequent pregnancies
If MCA dopplers show fetal anemia, what do you do?
offer fetal transfusion
treatment for newborn jaundice?
phototherapy - UV light or UV blanket frequent feedings
blocks IgG from being developed and is a blood product so some pts may decline
rhogam
what babies should you monitor for jaundice?
those w/ hematomas, ABO incompatability, RH negative moms
if titer of 1:8 is reached, what should you do?
titer no longer useful, switch to MCA doppler Q 1-2 weeks
how to treat fetal anemia?
tx w/ blood transfusion done in umbilical vein; done by perinatology under under ultrasound guidance (percutaneous umbilical sampling)
If father's blood is RH positive (DD) and mother's blood is RH negative (dd), what are the chances that baby will be RH positive?
100% Will have all Rh positive babies
If father's blood is heterozygous RH positive (Dd) and mom's blood is RH negative (dd), what are the chances that baby will be RH positive?
50% dd (RH - ) 50% Dd (RH + )
if woman is pregnant and called w/ bleeding or abdominal trauma, what should you do??
ALWAYS CHECK BLOOD TYPE
why do infants with HDN end up w/ heart failure and fluid build up?
HYDROPS: more immature RBCs produced in bone marrow, liver, spleen; organs become enlarged and can't keep up w/ anemia; heart fails
which can cross placenta, IGM or IGG?
IGG think: IGG GOES across placenta
how to give rhogam?
IM, w/in 24 hours of potential exposure to fetal blood, at 28 weeks, then, if baby is RH + after birth
exposure to RH factor will stimulate formation of ___ in mothers
IgG anti-D antibodies
how often to do antibody titers and until what point?
Q 4 weeks, until titer 1:8 is reached; higher than 1:8 (e.g. 1:16?) monitor w/ MCA (fetal middle cerebral artery) doppler every 1-2 weeks started at 18 wks
protein expressed on surface of RBCs; RBC antigen (D)
RH factor named after rhesus monkey
name ways fetal antigens can get into maternal blood stream?
- ectopic pregnancy - miscarriage - abdominal trauma - induced abortion - amniocentesis/ CVS - abruption - external cephalic version (turning baby from breech to head first) - delivery
baby born to RH negative mom or have other risk factors for jaundice, what do you do?
- evaluate cord blood - if baby +, give mom rhogam - monitor bilirubin
what happens in HDN (hemolytic dz of newborns)
- mom makes antibodies --> rapid destruction of RBCs --> anemia in fetus (can't carry O2) --> fetus produces more RBCs (but their immature erythroblasts that produce bilirubin) --> enlargement of bone marrow, liver, spleen --> heart failure and fluid buildup (hydrops)
what does prenatal management of RH - mothers w/ no antibodies include?
- review prenatal bloodwork - discuss rhogam - w/ bleeding or abdominal trauma, review if rhogam needed (if it was given w/in prior 12 weeks, no repeat dose) - repeat antibody screen at 28 wks, if - give rhogam - after birth, if baby RH +, give mom another dose rhogam
when to screen for RH factor?
- w/ initial prenatal labs - at 28 wks - anytime potential transfer of fetal blood to maternal stream
