By Erin K Costello
While searching for post material in the anti-vaccine Facebook groups we often stumble across a post asking for advice on the RhoGAM shot given during pregnancies that are at risk. Sadly, we also often see some dangerous advice being given as a result. Before I explain what I mean, let's first understand what the Rh factor is during pregnancy.
Each person has a blood type that falls into one of the four major types; A, B, AB, or O. Each person's blood type is determined by the types of antigens on the blood cells. Antigens are proteins on the surface of blood cells that can cause a response from the immune system. Rh in Rh factor stands for Rhesus. Rhesus is a type of protein on the surface of red blood cells. Those who have the protein are known as Rh positive. This is the most common Rh type. About 85% of the population have the Rhesus protein. Those who do not are known as Rh negative. Normally, being Rh positive or Rh negative has no impact on one's health or life. The only times this comes into play is during pregnancy. Even then this is only a factor when the mother is Rh negative, and the father is Rh positive. If the fetus is also Rh negative like the mother is, then this will not be a problem. However, it is slightly more common at 60% the fetus will inherit the father's Rh positive protein.
If Rh positive blood mixes with Rh negative blood, the Rh negative blood will develop antibodies to attack the Rhesus proteins found in the Rh positive blood. If the mother is found to be Rh negative, and the fetus could be Rh positive, the pregnancy is treated as though the fetus is Rh positive. In a first pregnancy this usually doesn't cause a problem. However, it will likely affect all future pregnancies if there are not preventative measures taken.
When the mother's blood has been exposed to Rh positive blood, this is known as sensitization. When a woman's blood has become sensitized it means she has already developed anti-bodies to the Rh positive blood proteins. It is unknown exactly how much blood is needed to cause sensitization but many woman develop this with as little as 0.1mL of Rh positive blood. When Rh negative blood is first sensitized it takes several weeks to develop immunoglobulin M, or IgM, antibodies. IgM antibodies are too large to cross the placenta. Because of this, the Rh positive fetus that triggers maternal sensitization is often times unharmed.
When the woman's blood has had prior exposure to Rh positive blood and has been sensitized, the immune system quickly reacts to Rh positive blood. This is usually seen during a second pregnancy of an Rh positive fetus. Usually within hours of the new exposure, smaller immunoglobulin G, or IgG, anti-bodies are formed. IgG anti-bodies can cross the placenta and destroy fetal red blood cells. This causes Rh disease, which can be dangerous for the fetus, possibly even fatal.
A woman's blood can become sensitized in a number of ways. The most common way though is through fetomaternal hemorrhage, which is when there has been entry of the fetal blood into maternal circulation before or during labor and delivery. The mother's blood can be exposed to the fetus' blood in both vaginal deliveries, and c-sections. Because of this it is common to find the blood to have been sensitized prior to a second pregnancy. Other ways sensitization can happen are, miscarriage, amniocentesis, chorionic villus sampling, ectopic pregnancy, removal of a molar, cordosentesis, placental abruption, manual extraction of placenta, external version (breech repositioning), abortion, or other trauma to the mother and fetus such as a car accident.
If the mother has been sensitized, and becomes pregnant with a second Rh positive fetus, the antibodies already in her blood could attack the baby's red blood cells, causing Rh disease. This can cause the fetus to have anemia, jaundice, or more serious problems. These problems with Rh disease usually end up becoming worse with each subsequent Rh positive pregnancy. There are no warning symptoms of Rh disease. Only testing for sensitization in the first trimester can determine if a fetus is at risk or not. This blood test will show if a woman's blood already has antigens or not. If the blood does have them, then there has been previous exposure, if no antigens then no previous exposure. If the blood test shows there to be no previous sensitization then the test will likely be repeated through out the pregnancy to determine whether or not this has changed. The test is routinely repeated between 24-28 weeks of pregnancy but can be done again in instances of trauma, amniocentesis, or placenta abruptio. Other than these instances, the baby will have a blood test at birth to determine it's Rh factor. If the baby is Rh positive, the mother will be tested to see if she was sensitized during pregnancy or birth.
If a mother is found to have been sensitized prior to a pregnancy, she may have to undergo regular blood tests to check the level of antibodies in her blood, a Doppler ultrasound to check blood flow to the baby's brain (this can show anemia and how severe it is), and an amniocentesis after 15 weeks to check the baby's blood type and Rh factor to look for problems. Problems such as anemia can break down the fetus' red blood cells creating a condition called hemolytic disease, or hemolytic anemia. This can cause serious illness, brain damage, or even death in a fetus or newborn. Often times this condition will require an early delivery or even a blood transfusion for the fetus while still in utero.
Due to the health and development problems sensitized blood can cause a fetus, it is often suggested a mother receive a shot of RhoGAM at various points during pregnancy and delivery. RhoGAM is Rh immune globulin, which is a blood product designed to prevent the mother's blood from developing anti-bodies to the fetus' Rh positive proteins. Without the shot, the mother's immune system will essentially see the fetus, more specifically the fetus' blood, as an antigen. In other words, the mother's body becomes allergic to the fetus and her immune system will attack the fetus. Rh immune globulin prevents this from happening. Once the blood has been sensitized though, and anti-bodies have formed, the Rh immune globulin will no longer have an effect on the formation of anti-bodies, rendering the shot essentially useless. This is why it is so important to treat Rh negative blood before it becomes sensitized
The way to most effectively prevent sensitization from occurring is after the first delivery of a Rh positive baby. Once it's been tested and discovered the baby is Rh positive, the mother will then receive a shot of RhoGAM to prevent the possibility of anti-bodies forming in the mother's blood. In future pregnancies, RhoGAM will also be given at about 28 weeks of pregnancy, then again after delivery of a Rh positive baby.
The advice we often see given in these anti-vaccination groups is for mothers to skip the 28 week pregnancy shot and only agree to the RhoGAM after delivery of a Rh positive baby has been established. The problem with this advice though is that sensitization can occur before delivery. Usually during some form of trauma or through certain tests performed during pregnancy. Since there are no symptoms of sensitization having happened, it's impossible for an expecting mother to know her blood has already been exposed and is developing anti-bodies before delivery. Once anti-bodies have formed in her blood, the Rh immune globulin will be useless against preventing future anti-bodies. This is why it is so important to receive the RhoGAM shot at both the 28th week of pregnancy, and upon childbirth when the baby is found to be Rh positive.
Being O positive myself, Rh was never a factor for me during pregnancy. I barely knew or understand much about Rh or why it was a concern. It wasn't until I met my fiance that I learned more about this issue and the heartache it can cause. The Rh factor wasn't discovered until 1940 by K. Landsteiner and A.S. Wiener. As a result, the Rh immune globulin wasn't widely available medically until the 1960s. My fiance's mother was an only child, born in the 1950s. She would've had a younger brother and a younger sister had the Rh immune globulin been available at the time of her birth. As a result, my fiance would've had an aunt and an uncle in his life growing up. But, what hits my heart most of all, is imagining what his grandmother's life must have been like after losing two newborns. I imagine she would, like any mother would, end up wondering if there was anything she did wrong, and having to live with that guilt, regardless of how misplaced it would have been. I also feel such sadness when I imagine what having to live with the incredible hole in her heart the loss of two newborns would sculpt into being.
I have never personally lost a potential family member or a child myself due to the Rh factor. But knowing what my fiance's family has been both forced to live without, and forced to live with, is more than enough to anger me each time I see such ignorant, dangerous, and flippant advice given in the anti-vaccination groups. I don't want to see or hear of another family having to experience such pain and loss, especially if such heartache can be prevented. So let me state on behalf of all admins at What's The Harm; PLEASE, we urge and beg anyone reading this, whether you are facing a possible Rh pregnancy or any other health concern for that matter, never take medical advice from strangers on Facebook. Always talk to your doctor about your options and together the two of you can decide what is best for you at that time.