Rh sensitization and ABO incompatibility
Question and Answers
define Rh incompatibility -correct answer- occurs when an Rh-negative mother (one
negative for a D antigen or one with a dd genotype) carries a fetus with an Rh-positive
blood type (DD or Dd genotype).
Define hemolytic disease of the newborn aka erythroblastosis fetalis -correct answer-
A condition that a fetus can become so deficient in RBBC that sufficient oxygen
transport to body cells cannot be maintained.
Give an example (situation) of Rh incompatibility with father/mother -correct answer-
For such a situation to occur, the father of the child must either be homozygous (DD) or
Dd genotype). For such a situation to occur, the father of the child must either be
homozygous (DD) or heterozygous (Dd) Rh-positive. If the father of the child is
homozygous (DD) for the factor, 100% of the couple's children will be Rh-positive (Dd).
If the father is heterozygous for the trait, 50% of their children can be expected to be
Rh-positive (Dd). Although this is basically a problem that affects the fetus, it causes
such concern and apprehension in a woman during pregnancy that it becomes a
maternal problem as well.
If the father is homozygous for the factor (DD), how many of the couple's children will be
Rh-positive (Dd)? -correct answer- 100%
If the father is heterozygous for the trait, what percent of their children can be expected
to be Rh-positive (Dd). -correct answer- 50%
What antigen does people who have Rh-positive blood have that Rh-negative people do
not? -correct answer- they have a protein factor (the D antigen)
When a Rh-positive fetus begins to grow inside an Rh-negative mother who is
sensitized what is her body reaction? -correct answer- it is as though her body is being
invaded by a foreign agent. Her body reacts in the same manner it would if the invading
factor were a substance such as a virus; she forms antibodies against the invading
substance.
what do the maternal antibodies do in the body? -correct answer- The Rh factor exists
a a portion of the RBC, so these maternal antibodies cross the placenta and cause RBC
destruction (hemolysis) of fetal RBC. A fetus can become so deficient in RBC that
sufficient oxygen transport to body cells cannot be maintaine. This condition is termed
hemolytic disease of the newborn or erythroblastosis fetalis.
give some examples of when fetal blood might enter maternal circulation -correct
answer- theoretically, there is no connection between fetal blood and maternal blood
, during pregnancy, so the mother should not be exposed to fetal blood. However,
occasional villus ruptures, allowing a drop or two of fetal blood to enter the maternal
circulation. Procedures such as amniocentesis or percutaneous umbilical blood
sampling can also cause this.
during which pregnancy is this effect small? The first or second? -correct answer- first
pregnancy
during the birth of the first child there is an exchange of maternal blood from damaged
villi. So most of maternal antibodies are formed when? -correct answer- 72 hours after
birth. Most of the maternal antibodies formed against the Rh-positive blood are not
formed during pregnancy but in the first 72 hours after birth, making them a threat to a
second pregnancy.
What titer should all women with Rh-negative blood have at a first pregnancy visit -
correct answer- anti-D antibody titer
what is a normal and minimal titer range -correct answer- normal=0, minimal= 1:8
at what week will the test be repeated of the first tier is minimal -correct answer- 28 wk.
If the test is minimal it will be repeated at wk 28 of pregnancy. If this is also normal, no
therpay is needed.
what does an elivated anti-D antibody titer of 1:16 or greater mean and what will happen
-correct answer- If a woman's anti-D antibody titer is elevated at a first assessment
(1:16 or greater), showing Rh sensitization, the well-being of the fetus in the potentially
toxic environment will be monitored q 2 wks (or more often) by Doppler velocity of the
fetal middle cerebral artery, a technique that can predict when anemia is present or fetal
red cells are being destroyed.
I don't completely understand this..... -correct answer- If the artery velocity remains
high, a fetus is not developing anemia and most likely is an Rh-negative fetus. If the
reading is low, it means a fetus is in danger, and immediate birth will be carrie dout
providing the fetus is near term. If not near term, efforts to reduce the number of
antibodies in the woman or replace damaged red cells in the fetus are begun.
To reduce the number of maternal Rh (D) antibodies being formed, Rh (D) immune
globulin _____ is given -correct answer- RhIG immune globulin. To reduce the number
of maternal Rh (D) antibodies being formed, Rh (D) immune globulin RhIG , a
commercial preparation of passive Rh (D) antibodies against the Rh factor, is
administered to women who are Rh-negative at 28 wks of pregnancy.
Why can these not cross through the placenta -correct answer- These cannot cross
the placenta and destroy fetal red blood cells b/c the antibodies are not the IgG class,
the only type that crosses the placenta.
Question and Answers
define Rh incompatibility -correct answer- occurs when an Rh-negative mother (one
negative for a D antigen or one with a dd genotype) carries a fetus with an Rh-positive
blood type (DD or Dd genotype).
Define hemolytic disease of the newborn aka erythroblastosis fetalis -correct answer-
A condition that a fetus can become so deficient in RBBC that sufficient oxygen
transport to body cells cannot be maintained.
Give an example (situation) of Rh incompatibility with father/mother -correct answer-
For such a situation to occur, the father of the child must either be homozygous (DD) or
Dd genotype). For such a situation to occur, the father of the child must either be
homozygous (DD) or heterozygous (Dd) Rh-positive. If the father of the child is
homozygous (DD) for the factor, 100% of the couple's children will be Rh-positive (Dd).
If the father is heterozygous for the trait, 50% of their children can be expected to be
Rh-positive (Dd). Although this is basically a problem that affects the fetus, it causes
such concern and apprehension in a woman during pregnancy that it becomes a
maternal problem as well.
If the father is homozygous for the factor (DD), how many of the couple's children will be
Rh-positive (Dd)? -correct answer- 100%
If the father is heterozygous for the trait, what percent of their children can be expected
to be Rh-positive (Dd). -correct answer- 50%
What antigen does people who have Rh-positive blood have that Rh-negative people do
not? -correct answer- they have a protein factor (the D antigen)
When a Rh-positive fetus begins to grow inside an Rh-negative mother who is
sensitized what is her body reaction? -correct answer- it is as though her body is being
invaded by a foreign agent. Her body reacts in the same manner it would if the invading
factor were a substance such as a virus; she forms antibodies against the invading
substance.
what do the maternal antibodies do in the body? -correct answer- The Rh factor exists
a a portion of the RBC, so these maternal antibodies cross the placenta and cause RBC
destruction (hemolysis) of fetal RBC. A fetus can become so deficient in RBC that
sufficient oxygen transport to body cells cannot be maintaine. This condition is termed
hemolytic disease of the newborn or erythroblastosis fetalis.
give some examples of when fetal blood might enter maternal circulation -correct
answer- theoretically, there is no connection between fetal blood and maternal blood
, during pregnancy, so the mother should not be exposed to fetal blood. However,
occasional villus ruptures, allowing a drop or two of fetal blood to enter the maternal
circulation. Procedures such as amniocentesis or percutaneous umbilical blood
sampling can also cause this.
during which pregnancy is this effect small? The first or second? -correct answer- first
pregnancy
during the birth of the first child there is an exchange of maternal blood from damaged
villi. So most of maternal antibodies are formed when? -correct answer- 72 hours after
birth. Most of the maternal antibodies formed against the Rh-positive blood are not
formed during pregnancy but in the first 72 hours after birth, making them a threat to a
second pregnancy.
What titer should all women with Rh-negative blood have at a first pregnancy visit -
correct answer- anti-D antibody titer
what is a normal and minimal titer range -correct answer- normal=0, minimal= 1:8
at what week will the test be repeated of the first tier is minimal -correct answer- 28 wk.
If the test is minimal it will be repeated at wk 28 of pregnancy. If this is also normal, no
therpay is needed.
what does an elivated anti-D antibody titer of 1:16 or greater mean and what will happen
-correct answer- If a woman's anti-D antibody titer is elevated at a first assessment
(1:16 or greater), showing Rh sensitization, the well-being of the fetus in the potentially
toxic environment will be monitored q 2 wks (or more often) by Doppler velocity of the
fetal middle cerebral artery, a technique that can predict when anemia is present or fetal
red cells are being destroyed.
I don't completely understand this..... -correct answer- If the artery velocity remains
high, a fetus is not developing anemia and most likely is an Rh-negative fetus. If the
reading is low, it means a fetus is in danger, and immediate birth will be carrie dout
providing the fetus is near term. If not near term, efforts to reduce the number of
antibodies in the woman or replace damaged red cells in the fetus are begun.
To reduce the number of maternal Rh (D) antibodies being formed, Rh (D) immune
globulin _____ is given -correct answer- RhIG immune globulin. To reduce the number
of maternal Rh (D) antibodies being formed, Rh (D) immune globulin RhIG , a
commercial preparation of passive Rh (D) antibodies against the Rh factor, is
administered to women who are Rh-negative at 28 wks of pregnancy.
Why can these not cross through the placenta -correct answer- These cannot cross
the placenta and destroy fetal red blood cells b/c the antibodies are not the IgG class,
the only type that crosses the placenta.
