Rh Sensitization

Rh factor

Known as the Rhesus factor

Rh factor

A protein that can be present (Rh+) or absent (Rh-) on the surface of red blood cells.

Rh factor

Inherited through an autosomal dominant pattern. This means that if you inherit at least one Rh-positive allele from either parent, you will be Rh-positive, and you need to inherit two Rh-negative alleles to be Rh-negative.

Rh incompatibility

when the mother who is Rh- is carrying a Rh+ fetus

Rh sensitization

when the mother’s immune system creates antibodies to attack fetus’ RBC

Rh sensitization

when antibodies drive the immune system to attack against the fetus’ RBC

Rh sensitization

A condition where an Rh-negative mother develops antibodies against the Rh-positive blood of her fetus, occurs when fetal blood crosses the placenta and enters the mother's bloodstream, leading to the production of anti-D antibodies.

anti-D antibodies

antibodies created against the fetus’ RBC

labor and delivery

common reason why the fetal blood crosses the placenta and enters the mother’s bloodstream

Rh Incompatibility

primary cause of Rh sensitization

Feto-Maternal Hemorrhage

during pregnancy, fetal red blood cells (RBCs) can leak into the maternal circulation

Amniocentesis

a prenatal test in which a sample of the fluid that surrounds and protects a baby in the uterus (amniotic fluid) is removed for testing or treatment

Chorionic villus sampling

a prenatal test in which a sample of the wispy projections that make up most of the placenta (chorionic villi) is removed for testing

Cordocentesis

a prenatal test in which a sample of the baby's blood is removed from the umbilical cord for testing

external cephalic version (ECV)

the manual rotation of a baby in a breech position

D antigen

most commonly triggers hemolytic disease of the fetus & newborn detected by the mother’s antibodies

IgM type

initial antibody type of maternal anti-D antibodies that does not cross the placenta

IgG type

antibody type of maternal anti-D antibodies after a repeat exposure to the D-antigen that can cross the placenta

little or no anemia

prognosis for mildly affected infants

Anemia + hyperbilirubinemia/jaundice

prognosis for moderately affected infants

Kernicterus

severe case of fetal hyperbilirubinemia

Kernicterus

a neurologic syndrome caused by deposition of bilirubin into central nervous system tissues

Kernicterus

occurs several days after delivery and is characterized by loss of the Moro (ie, startle) reflex, posturing, poor feeding, inactivity, a bulging fontanelle, a high-pitched shrill cry, and seizures

moro reflex

reflex lost in infants with kernicterus

Kernicterus

Infants who survive this may go on to develop hypotonia, hearing loss, and intellectual disability.

Erythroblastosis fetalis

characterized by severe hemolytic anemia and jaundice.

Erythroblastosis fetalis

very serious life-threatening condition observed in infants affected by Rh incompatibility

hydrops fetalis

most severe form of erythroblastosis fetalis

hydrops fetalis

Newborns are extremely pale with hematocrits usually less than 5

hydrops fetalis

often results in death of the infant shortly before or after delivery and requires an emergent exchange transfusion if there is to be any chance of infant survival

3-4 days after delivery

normal physiologic jaundice

fetal autoimmune hemolysis

The binding of maternal Rh antibodies produced after sensitization with fetal Rh-positive erythrocytes results in this

Hemolytic Disease of the Newborn

During subsequent pregnancies the maternal response to re-exposure to the fetal D antigen can result in a rapid production of IgG anti-D antibodies that can cross the placenta into the fetal circulation

Hemolytic Disease of the Newborn

results in production of bilirubin

Mild Hemolysis

The placenta has some capacity to remove bilirubin from the fetal circulation, and mild levels of hemolysis can typically be well tolerated by the fetus. Upon birth, the neonate may have a mild anemia & signs of jaundice that may resolve without treatment

Moderate to Severe Hemolysis

After birth, the bilirubin levels may increase because the neonate's liver is underdeveloped at birth & unable to fully metabolize bilirubin

first 24 hours

subsequent rise in bilirubin levels can result in bilirubin entering the brain to produce potentially permanent, or even fatal neurological damage (kernicterus) during this time

exchange transufsion

management done for hydrops fetalis

Rh blood type

required blood test in every pregnant female

Rosette screening test

for RH negative pregnant;

can detect alloimmunization caused by very small amounts of fetomaternal hemorrhage

Kleihauer-Betke acid elution test

performed when a high clinical suspicion of large fetomaternal hemorrhage is present (>30 mL blood)

Kleihauer-Betke acid elution test

a quantitative measurement of fetal red blood cells in maternal blood, and it can be valuable for determining if additional amounts of Rh IgG should be administered.

Maternal Rh antibody titers

suggest that Rh sensitization has occurred, and further studies, such as amniocentesis and/or cordocentesis, may be necessary to evaluate the health of the fetus

Rosette screening test

a test done to know if the mother already developed anti-D antibodies

NST and ultrasound

postnatal emergency care during intrapartum monitoring

ABO blood group and Rh type, Hematocrit and Hemoglobin levels, serum bilirubin analysis, obtain a blood smear, direct coombs’ test

postnatal emergency care to examine infant blood

Hematocrit and hemoglobin levels

infant blood test used to detect anemia and its severity

serum bilirubin analysis

infant blood test used to detect possible jaundice and its severity + the management that can be done

positive coombs test

confirms the diagnosis of antibody-induced hemolytic anemia, which suggests the presence of ABO or Rh incompatibility

emergent exchange transfusion

required in infants born with erythroblastosis fetalis, hydrops fetalis, or kernicterus

Rh immunoglobulin

a medication that stops the body from making Rh antibodies if it has not already made them

Rh immunoglobulin

can prevent severe fetal anemia in a future pregnancy

Intramuscular

how is RhoGAM given

routine use of Rh D immune globulin

responsible for the reduced rate of red cell alloimmunization in more economically developed countries

at 28 weeks and within 72 hours

when should you administer the RhoGAM?

at 28 weeks

Given at a specific week of pregnancy, this destroys Rh-positive cells in the woman’s body

Within 72 hours after the delivery

The greatest chance that the blood of an Rh-positive fetus will enter the bloodstream of an Rh-negative woman happens during delivery

repeat dose

Each pregnancy and delivery of an Rh-positive baby requires

300 mcg of Rh IgG IM

Rh-negative non immunized woman who presents with antepartum bleeding or potential fetomaternal hemorrhage should receive …

50-mcg dose preparation of Rh IgG

recommended for Rh-negative females who have termination of pregnancy in the first trimester when fetomaternal hemorrhage is believed to be minimal.