When Is the RhoGAM Shot Needed?
If you are Rh negative, meaning that your blood does not contain the Rh factor protein, your doctor will probably recommend that you get an Rh immune globulin shot (such as RhoGAM) within 72 hours of the start of your bleeding from pregnancy loss. The RhoGAM shot is also given during and after pregnancy to prevent the same issues in future pregnancies.
Why get the shot? With the RhoGAM shot, you have lower odds of developing antibodies (becoming sensitized) against Rh-positive blood from this pregnancy; if you have circulating antibodies against Rh factor, you can face problems in future pregnancies.What if you wait too long? If given later than 72 hours after the start of the miscarriage, the shot is not likely to make a difference. However, it has been more than three days since your miscarriage, however, don’t panic. The odds that you have become sensitized against Rh factor are low.Is it necessary? Although there’s no strong evidence that the shot is totally necessary after a first-trimester pregnancy loss, the shot is low-risk, so doctors recommend it after any pregnancy bleeding because of the theoretical risk of Rh sensitization.
It is still a good idea to get a RhoGAM shot within the recommended time span if you can, as it makes the small risk of Rh sensitization even lower. There’s much more evidence on the shot’s necessity after a later pregnancy loss or after giving birth.
Rh Factor and Its Impact On Pregnancy
Rh factor is a protein that the majority of people carry in their blood. Roughly 85% of the population is Rh-positive, and Rh status is genetically determined.
If the baby has one parent who is Rh-negative and one who is Rh-positive, the baby has at least a 50% chance of being Rh-positive (Rh-positive status is a dominant genetic trait).Birthing parents who are Rh-positive, and who are Rh-negative with Rh-negative partners, do not need to worry about RhoGAM shots because Rh incompatibility is impossible.
In first pregnancies, Rh sensitization is rarely a problem because the parent’s blood and the baby’s blood typically do not interact directly until delivery—but if Rh-positive blood (such as from the baby) enters the Rh-negative parent’s blood, their immune system may develop antibodies against Rh factor.
How RhoGam Helps
RhoGAM pre-stocks the parent’s blood with the antibodies to the Rh factor protein. This prevents their immune system from needing to create antibodies to Rh factor in the event of encountering Rh-positive blood. Injecting the antibodies is safer than risking sensitization. This is because RhoGAM antibodies eventually clear the bloodstream, meaning that if the parent’s blood mixed with the baby’s in the future, the immune system would not have learned to create antibodies against Rh factor and the baby would not get anti-Rh antibodies. If a birthing parent’s blood is sensitized to Rh factor, the sensitization may be permanent and they risk delivering anti-Rh antibodies to future babies.
How It’s Given
As a part of the blood testing in standard prenatal care, most doctors check the blood type in order to identify Rh incompatibility. Originally, recommendations were to give the injections to people who had given birth. The recommendations then changed to include a RhoGAM shot around 28 weeks of pregnancy. Although few studies exist on using Rh immune globulin for first-trimester miscarriages, many doctors do recommend them because of a theoretical risk of sensitization after miscarriages with the idea that the potential benefits outweigh the minimal risk.
What If You Weren’t Given RhoGAM?
If you did not get a RhoGAM shot, do not panic. Remember that the risk of sensitization after a miscarriage is relatively small. However, you should inform your doctor about your concern. Your doctor can order a blood test to check your Rh sensitization status. In the event that you did develop anti-Rh antibodies, treatments for Rh incompatibility do exist and your doctor will know to observe your future pregnancies closely for signs of problems so as to intervene early if needed.
