Human blood broadly falls into two categories – Rhesus positive or Rhesus negative. The type you have will depend on whether a distinctive molecule, known as a RhD antigen, is present on the surface of your cells. Whether or not this is present is the result of inheritance and you may not have the same blood profile as your mother. Pregnant women who have RhD negative blood are at risk of suffering from rhesus disease if their child has a RhD positive blood group inherited from their father. This is done by administering intramuscular injections of a medication called Rho(D) Immune Globulin.
The reason for administering this injection is that healthcare practitioners are trying to avoid a process known as sensitisation where exposure to RhD positive blood causes the mother to develop an adverse immune response that can be harmful to the child. The Rho(D) Immune Globulin blood product does this by neutralising any RhD positive antigens that may have entered the mother’s blood during pregnancy. That’s because where antigens have been neutralised, the mother’s blood won't produce antibodies.
Expectant mothers are offered anti-D immunoglobulin if it’s suspected that RhD antigens from your baby have entered their blood – for example, if there is significant or worrying bleeding during pregnancy. It is also administered due to necessary invasive procedures (such as amniocentesis) where there are incidences of abdominal injury, or after delivery of the child.
Anti-D immunoglobulin is also routinely given during the third trimester of pregnancy because it's likely that small amounts of blood from your baby will cross the placenta into the mother during this final stage of fetal development.
Rho(D) immune globulin is also used to treat the serious blood condition known as immune thrombocytopenic purpura (ITP) when it occurs in patients that have Rh-positive blood. Sufferers of ITP are known to have very low platelets levels and experience insufficiencies in their ability to clot their blood and may suffer excessive bruising and bleeding.
Generally, this is a medicine which must be carefully prescribed and monitored and, as such, should only be given under the advice and supervision of your doctor. The prescription you are given may be for a powder for solution, a pre-prepared solution or in an injectable form of this drug.
Rho (d) immune globulin has a significant therapeutic impact in the management of a variety of conditions but may also cause some unwanted side effects which should be monitored and potentially treated. It is not certain that any or all of these will occur but if they do you may need to seek advice and support from your primary care practitioner.
The majority of the side effects listed below are thankfully rare. The most common reaction to the injection is a short-term allergic reaction which usually has fairly low-level symptoms similar to the flu which may or may not include a rash. If you become aware of any of the following, more unusual, side effects then speak to your healthcare provider as soon as possible.
Although it is important to consult your healthcare provider, many of these side effects may disperse without treatment as your body adjusts to the new drug regime.
The prescribed dosage of this medication will depend significantly on the intended therapeutic effect. Where it is being administered to an adult for Idiopathic (Immune) Thrombocytopenic Purpura then it is usually 50 mcg per kg of the patient’s weight – administered by drip.
For Rh-incompatible pregnancy, the usual dose is 300 mcg by injection at a gestation of between 26 and 28 weeks. This should be administered three days (72 hours) of the birth of a baby with an incompatible blood group.
Where the medication is being given because the mother is to undergo amniocentesis and chorionic villus sampling before 34 weeks gestation the usual dose is 300 mcg by injection immediately after the procedure. After 34 weeks then 120 mcg should be given within 72 hours.
If given for abortion or miscarriage before 12 weeks gestation then 50 mcg should be injected to the muscle within the same 72 hours window after pregnancy termination (or concerns over pregnancy termination.) After the pregnancy has passed 12 weeks of gestation, the dose is 300 mcg. Ectopic pregnancy also requires a 300 mcg dose.
The same dose is suggested for excessive fetomaternal haemorrhage within 72 hours of complication, with the addition of 20 mcg per mL of fetal red blood cells (in excess of 15 mL) where transplacental bleeding is quantified.
In the case of this medication being given for obstetric complications or invasive procedures then a dose of 300 mcg is recommended. The same dose is suggested for threatened abortion at any time and threatened pregnancy loss after 12 weeks gestation with continuation of pregnancy.
Due to the nature of this medication as a derivation of a naturally occurring human substance, there is a long list of other medications which rho (d) immune globulin may react with. If you are on an existing drug regime then you should take care to consult your primary care provider to ensure there are no areas of concern. As such you need to be completely honest with your doctor about any drugs you may be taking, or have recently taken.
The current list of medications which risk interaction with this drug include:
In addition, there are four disease interactions where the interplay between rho (d) immune globulin and normal disease processes may cause problems. These include:
There are a number of patient groups for whom this medication is not suitable and may have significant adverse effects. In particular, it should not be used for people with:
It is also not appropriate to use this medication for the suppression of isoimmunization in infants.
There are also some associated risks in administering this product. In particular, there have been concerns over the possibility this drug can induce cases of intravascular hemolysis (IVH) - a blood condition which can prove fatal. This dangerous side effect can also result in dangerous anemia and multi-system organ failure.
Warnings are also in place in relation to this medication and associated conditions around problems with the kidneys, failure of the kidneys and the entire renal system or blockages of the veins. It should also be noted that the liquid formulation of this product contains maltose and so can give misleadingly high blood glucose levels.
The final warning relating to this product is a reminder that it is constituted of human plasma and may therefore contain infectious agents, such as viruses, that can cause disease. Steps have been taking to implement screening of plasma donors to cut this risk but there is still some small risk of infection when using these products. Conditions which could potentially be transmitted include infectious agents such as viruses or the agent of Creutzfeldt-Jakob disease (CJD).
The intramuscular formulation used for this medication should be stored between 2°C to 8°C (35°F to 46°F) and should not be frozen. It should also be protected from light and discarded after use.
This vital tool in the doctor’s arsenal of preventative medications has improved the outcomes for both mothers and babies where the two do not share the same blood group by circumventing the process where the mother’s body may produce antibodies that harm the child she is carrying. It does this by avoiding the process of sensitisation which can lead to miscarriage. It is also given to patients that have low numbers of platelets and so may suffer from excessive bleeding or bruising.
The dosage required will depend significantly on the required outcome but is most usually delivered intramuscularly during the third trimester of pregnancy, after abdominal injury, after signs of miscarriage such as abdominal bleeding or after delivery of the infant. It is usually considered safe due to extensive screen procedures but using this drug does carry some small risk of infectious diseases such as viruses or other blood-borne conditions. Persons with history of allergic reactions should not be encouraged to take this medication and if and when side effects become apparent they should be discussed with a healthcare practitioner as soon as possible.