Ep 170: Being Rh Negative and Your Baby


In this episode of the podcast you’re going to learn what it means to be Rh negative and the implications for pregnancy. The short story is that Rh negative has to do with your blood type. If you’re Rh negative and your baby is Rh positive, it can potentially cause problems for the baby.

Alloimmunization is what occurs when an RH negative mom's immune system is exposed to the baby’s Rh positive cells. When this happens the mom's immune system may attack the baby's red blood cells.

 
 There are effective treatments and not all exposure will necessarily result in alloimmunization however it’s very important to take this seriously. If you take one thing away from this episode it’s that prevention is key. It's the best way to keep your baby safe.

In this Episode, You’ll Learn About:

  • What the blood group systems are and what that means
  • What the most common blood types are
  • What alloimmunization is and when it occurs
  • Why she leaned towards a c-section from the outset
  • How to prevent it
  • What are the fetal/neonatal consequences of alloimmunization
  • What types of screenings are done
  • What rhogan is, how it works, and the safety of it
  • List What can you do if alloimmunization has occurred

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Transcript

Dr. Nicole Rankins (00:00): What exactly does it mean to be RH negative? And what does it have to do with your baby? Welcome to the All About Pregnancy & Birth podcast. I'm Dr. Nicole Calloway Rankins, a board certified OBGYN who's been in practice for nearly 15 years. I've had the privilege of helping over 1000 babies into this world, and I'm here to help you be calm, confident, and empowered to have a beautiful pregnancy and birth. Quick note, this podcast is for educational purposes only and is not a substitute for medical advice. Check out the full disclaimer at drnicolerankins.com/disclaimer. Now let's get to it.

Dr. Nicole Rankins (00:53): Hello. Hello. Welcome to another episode of the podcast. This is episode number 170. I'm so glad that you are spending some time with me today. In this episode of the podcast, you are going to learn what it means to be RH negative and the implications for pregnancy. Now, the short story is that RH negative has to do with your blood type. And if you are RH negative and your baby is RH positive, it can potentially cause problems for the baby. So in order to understand that further, I'm gonna break it down for you, what the blood group systems are, what that means, and that's the A, B, AB, O, and then the positive or negative as well as what as alloimmunization is, what hemolytic disease of the newborn is, what type of screening we do. And then what something called Rhogam is, what it is, how it works, the safety of it, and what that has to do with this, with this as well.

Dr. Nicole Rankins (01:54): Now, before we get into the episode, let me do a quick listener shout out. This is from KT Jack, and she says, great podcast for pregnancy, birth preparation, and postpartum. I discovered this podcast at the beginning of my second, which is my current pregnancy. And I am so glad I did. Dr. Rankins is knowledgeable and informative. Her kindness and compassion are evident in each episode in the way she speaks. And in the way she interacts with guests, I highly recommend this podcast. And then it says, Dr. Rankins, will you come to Maryland to deliver my baby in a few weeks? I would absolutely love to come deliver your baby. I would love to deliver everyone's baby, who is listening to this podcast. And unfortunately I cannot, but the next best thing is to join me inside the Birth Preparation Course. The Birth Preparation Course is my signature online childbirth education class.

Dr. Nicole Rankins (02:45): That gets you calm, confident, and empowered to have a beautiful birth. And it does that through my five step beautiful birth prep process, where you set the tone for your birth, getting your mindset, your support for your birth right. You really need to do that before you learn anything about labor and birth. In step two, you learn all the details of labor and birth, and what's happening in your body during labor and birth. And then step three is possible things that may happen during your labor and birth. So you're prepared for those potential curve balls. Step four is getting ready for the postpartum period. And then step five is making birth wishes, AKA a birth plan that's actually gonna work to help you have the birth that you want. And you can find all the details of the Birth Preparation Course at drnicolerankins.com/enroll. Over a thousand women have joined us inside the Birth Preparation Course.

Dr. Nicole Rankins (03:36): And I would love to have you there too. Okay. So let's get into the episode about RH negative. First thing we're gonna talk about are blood group systems and what the blood group systems are is this is the way that we tell our blood type and specifically the type of red blood cells we have. Now, the surface of every red blood cell on our body is coded with something called antigens. These are sugars and proteins, and they are linked to the outside of the red blood cell. And these are important because these molecules can cause an immune response from the immune system, potentially leading to a transfusion transfusion reaction or an organ rejection, if you are given the wrong type of red blood cell, okay. Now there are actually 43 blood group systems that are recognized by the international society for blood transfusion. However, the most common system that we use is the ABO blood group system.

Dr. Nicole Rankins (04:46): Okay. So that is responsible for the four major red blood cell types. That's A, B, AB and O. So if you have A, that means that you have the A antigen on your red blood cells. It also means that in your system, you have something called antibodies to B, and that's gonna be important in a minute. If you have type B blood, you have the B antigen also means you have antibodies against A, if you have AB, then you have both A and B antigen. And if you have type O, then you don't have either A or B. Okay. So A, you have the A antigen, B, you have the B antigen, AB, you have A and B, O you don't have either one. And I'll talk about the frequency of those in just a second. Now that's the O part. So what's the, or the, the letter part, what's the positive or negative part.

Dr. Nicole Rankins (05:45): Okay. So that's the RH phenotype. And if you do not have the RhD antigen specifically, we typically shorten it to RH, but it's really RhD antigen. If you don't have the RhD antigen, then you are RH negative. Okay. You're RH negative. So if you are O negative, then you don't have the, A, you don't have the B, you don't have the RH antigen, if you're O negative. All right. If you were O positive, that means you don't have the A, you don't have the B, but you do have the RhD antigen. And what that comes into play in terms of transfusion reactions is for example, if you are type A and you get type B blood, your type A system, your immune system is going to recognize that B antigen as foreign, and it's going to attack those cells and cause a transfusion reaction.

Dr. Nicole Rankins (06:52): Okay? So that's an example of how that could interact. Now, if you are type AB, and you have both A and B antigen, you can get A blood and it's gonna be fine, cuz you already have A antigen in your body. You can get B blood because that's already gonna be, that's gonna be fine. Cuz you have B antigen in your body. You can also get O blood because O doesn't have either AB. So that's why AB is known as the universal recipient. And if you're AB po- uh, negative, sorry, AB negative. That's the universal recipient cuz you can get, um, I'm sorry, AB positive. If you are AB positive, that's the universal recipient because you can get A blood, you can get B blood and you can get people who have the RH antigen. Okay. So that's the universal recipient. Universal donor is O negative.

Dr. Nicole Rankins (07:47): So when you're O negative and you don't have any of those antigens in your blood, then you can give your blood to anybody because it's not ever gonna be recognized as foreign because none of those antigens are there. So I hope that makes sense. In terms of universal donor use universal recipient, what A, B, AB and O are, and then you're either RH positive or RH negative. Now the different phenotypes or different types of red blood cells differ by race and ethnicity, but in general, most people, and this is in the US specifically, most people are O positive. That's the most common type of blood across all races and ethnicities. It varies a little bit. So for example, Black folks, um, about 47% of Black Americans are O positive. Uh, about 37% of White Americans are O positive 53% of Hispanic Americans, 39% of Asian Americans.

Dr. Nicole Rankins (08:50): Then the next most common type of blood is A positive. So 33% of White Americans are A positive. 24% of Black Americans are A positive. 29% of Hispanic Americans are A positive, 27% of Asian Americans are A positive and then the rest are kind of scattered. The next most common is B positive and then AB positive. And then after that is the, um, negative subtype. So then, O negative, A negative, B negative. B negative is the most rare type of blood. So most people are type O blood. Most people are also RH positive. Um, so it's most likely that you are RH positive, but again, there's a good number who can potentially also be, um, any of the letters and then also RH negative. Okay. So why do we care? Why is this important? And it's something called alloimmunization and specifically prevention of alloimmunization.

Dr. Nicole Rankins (09:55): So what is alloimmunization? So what that is is if you are RH negative, if you are a mom who's RH negative and you either deliver a baby who is RH positive, and the baby's gonna be RH positive, this is something that's inherited from your parents. So your blood type is inherited from your parents. If either one of your parents is RH positive, then that gives you the potential to be RH positive. Okay? So if you are a RH negative mom and you deliver a baby who is RH positive, or you are exposed to RH positive red blood cells. And I'll talk about how that exposure can happen. Then you are at D risk of developing what's called anti-D antibodies. So what that means is if you are RH negative, you are exposed to your baby's RH positive blood. You will recognize those red blood cells that are RH positive of your baby as foreign.

Dr. Nicole Rankins (10:57): Your immune system is going to make something called antibodies, okay? Anti-D antibodies, those antibodies can then cross the placenta and attack your baby's red blood cells. When they attack your baby's red blood cells, that leads to the risk of developing something called hemolytic disease of the fetus and newborn, which can lead to significant morbidity or even mortality, depending on how severe that is. All right. So I'm gonna say that one more time. Alloimmunization is when, if you are RH negative and you are exposed to RH positive cells, your immune system, as that RH negative person will see those RH positive cells as foreign, develop antibodies to those RH positive cells, those antibodies can cross the placenta attack the baby's red blood cells, and lead to severe anemia. So how might the mom's immune system get exposed to the baby's RH positive cells? So the most common cause is something called transplacental fetal maternal bleeding during pregnancy.

Dr. Nicole Rankins (12:25): This accounts for the vast majority of cases of mom's and baby's blood mixing. Now, typically in pregnancy, actually for all pregnancies, very, very tiny amounts, like as little as 0.1 milliliter of, of the baby's blood will get into the mom's blood system. And that's important. I'll explain why that's important in the context of this, but there are events that can cause even more bleeding in general. The amount of mixing between mom and baby is very, very, very low. The placenta actually functions to keep mom's baby and blood and BA um, mom's baby mom's blood and the baby's blood separate. So, uh, they really actually don't mix very much. Um, that's part of the reason why, like you can implant a pregnancy of any type of genetic makeup. You don't have to have the same genes and you can still carry a pregnancy that is not genetically related to you.

Dr. Nicole Rankins (13:23): The blood doesn't mix, the placenta is not recognized as foreign. Um, it's actually one of the, the miraculous or curious things about pregnancy and science, because, and I'm going on a side note here in any other organ transplantation, if you transplanted an organ that was genetically different, your body's gonna attack it, but it doesn't do that in pregnancy because the placenta keeps things very separate. However, there are some cases where, uh, more of the mom's and baby's blood can mix. All right? So the highest chances that that is going to happen is delivery. And this will you'll understand why this is important when we talk about, um, trying to prevent this from happen happening the blood mixing, but the highest chance's at delivery. And then other instances where mom's blood and baby's blood can mixed are an induced abortion. So an elective ending of pregnancy, a spontaneous abortion or miscarriage, ectopic pregnancy, something called chorionic villus sampling, where a sample of the placenta is taken in order to test for genetic problems.

Dr. Nicole Rankins (14:28): That's something that's done in the early part of, of pregnancy, any type of fetal procedure, for example, in rare instances where there's fetal surgery, for example, on a, a problem with the baby's spine, amniocentesis, external cephalic version, which is when we turn a breach baby, placenta abruption when the placenta separates away from the wall of the uterus prematurely, any type of bleeding that happens during pregnancy, um, removing the placenta at birth manually, not when it falls out on its own, but manually meaning we have to go in and, and get it out. Also abdominal trauma, like from a car accident, from a fall, if a mom is assaulted, all of those things can lead to mom's and baby's blood mixing. And then if mom is RH negative, her potentially developing antibodies, okay. Now some rare ways that a mom could develop anti-D antibodies would be if she were injected with a needle that was contaminated by RhD positive blood, um, that would obviously rarely happen in a healthcare situation. But if, um, there's a, a drug use situation going on, then that's a possibility also if there's inadvertent transfusion of RH positive blood. So for example, a RH negative mom got transfused RH positive blood that also rarely happens. There's a lot of things in place in order to prevent that from happening. Those are rare ways that things can mix. Uh, but most of the time it's going to be from the things that I mentioned from mom's and baby's blood mixing, particularly around delivery.

Dr. Nicole Rankins (16:08): And unfortunately, sometimes we don't know what causes this to happen for mom to get sensitized. Sometimes there, isn't always an identifying event that we know about, but these are the things that, um, we know are most likely to be associated with them. Now, if they mix and that alloimmunization occurs. So alloimmunization again, is that mom who's RH negative, she developed those antibodies, those antibodies go through the placenta and attack the baby's blood cells leading to hemolytic disease of the fetus and newborn. The severity of that anemia is influenced by how high the antibody concentration is. So that's the primary thing that influences how severe the disease is. And if those antibodies get really high, it can lead to something called hydrops fetalis, where there's a lot of attacking of the baby's red blood cells. And hydrops fetalis is two is two or more of the following things.

Dr. Nicole Rankins (17:11): It's skin edema. So the skin is very puffy and edematous with fluid. It's socities, where there is fluid in the baby's belly, paracardial effusion where there's fluid around the baby's heart, or plural effusion where there's fluid around the baby's lungs. And as you can imagine, those organ systems aren't gonna function properly if there's ext- extra fluid around there. So hydrops fetalis is something that increases the risk of stillbirth. So that's kind of the dreaded, um, worst case scenario of hemolytic disease of the newborn. And I'll talk about how it's treated in a minute. It can also cause low platelets. We're not exactly sure how it causes low platelets, cuz um, technically it really mostly attacks red blood cells, but sometimes it can cause low, low platelets. Those are what help the blood clot as well, as well as low white blood cells, but primarily it's attacking the red blood cells.

Dr. Nicole Rankins (18:05): So what do we do to prevent alloimmunization? Really there are two parts of it. One is screening and one is prevention. So the first thing is that at first prenatal visit, everybody gets a blood type. So we're going to get your A, B, AB, or O and then whether or not you're RH positive or negative and whether or not, if you are RH negative, do you have antibodies to D so do you have anti-D antibodies? So that happens at the first prenatal visit, that's called a type and screen. Your blood type and a antibodies screen. Okay. To make sure you don't have any antibodies. And we actually look for some other antibodies, but I'm keeping it fairly simple for the purposes of this conversation. But we look to make sure that you don't have any anti-D antibodies if you are RH negative.

Dr. Nicole Rankins (18:58): Okay. We also repeat that at 28 weeks to catch the rare circumstances if alloimmunization developed during the pregnancy. All right now, as for prevention, we do something called Rhogam, which is anti-D immune globulin. As I said before, if you're RH negative and you're exposed to positive cells, you're at risk for developing those anti-D antibodies and virtually every pregnant woman is going to be exposed to at least tiny amounts of their baby's blood. All right. Very tiny as tiny as 0.1 milliliters. So what we do is we give something called anti-D immune globulin during pregnancy and postpartum, and that has dramatically reduced the incidence of D alloimmunization. Okay. And the way that it works is that it's not a vaccine. Some people get confused and things that think it's a vaccine. It is not a vaccine. We don't exactly understand how it works, but what it does is it suppresses the formation of D antibodies by the mom's immune system. So when you get Rhogam, it suppresses your immune system from making those anti-D antibodies. All right.

Dr. Nicole Rankins (20:27): And where it comes from is it comes from pool pooled, plasma of donors. So it really comes from donors and pooling it from plasma. Um, there has been a lot of research to try to create a synthetic anti-D immune globulin so far none is available. So it really comes from donor blood and pooling plasma. And there are two doses that are available that are available. There's a smaller dose, that's 50 micrograms that has enough anti-D immune globulin to suppress the immune response to two and a half milliliters of positive, fetal red blood cells or five milliliters of fetal whole blood. Cause our blood is not just red blood cells. Our blood is red blood cells, plasma, white blood cells. And then there's a 300 microgram dose that we typically give for the most part. And I'll explain the differences of when we can give the different doses in just a second.

Dr. Nicole Rankins (21:23): But the typical dose that we give is 300 micrograms. And that is enough anti-D immune globulin to suppress the immune response from 15 milliliters of D positive, fetal red blood cells. And that's actually a lot or 30 milliliters, which is also a lot of fetal D positive whole blood. Okay. So it's available in two doses. It can be given in the muscle, which is how it's typically given, or it can be given through the IV. And they both work very well. And speaking of how well they work prior to the development of anti-D immune globulin, about 16% of D negative pregnant women will become alloimmunized after two births of a D positive baby. Okay. So, and the risk increases each time of alloimmunization because the most likely time that the blood is gonna mix is around is around delivery. So you get pregnant the first time delivery of that first baby is when the blood may mix.

Dr. Nicole Rankins (22:22): So then you're at higher risk for each subsequent pregnancy. Okay. So that's why 16% by after two births, cuz it goes up with each pregnancy. Well that rate fell to 1 to 2% with routine postpartum use of Rhogam. And then it was further reduced to 0.1 to 0.3% when it's given at 28 weeks in the third trimester. So it is actually very rare as long as Rhogam is given to see alloimmunization. All right. It's very rare to see it, um, because it works really, really well. Now it hasn't been completely eliminated because occasionally there are mistakes made and it's not given in accordance to medical society guidelines. Also some people have misconceptions about it and occasionally refuse the medication. Um, there's also a possibility that there was mixing of the babies baby's and mom's blood early in pregnancy before the third trimester dose was given. But for the most part, this has been eliminated because of the use of Rhogam.

Dr. Nicole Rankins (23:38): Now Rhogam is very safe. It is uh, made from plasma that is tested for hepatitis C, HIV, hepatitis B, parvovirus. It uses an ultra filtration technique to filter out viruses bacteria because of that allergic reactions are extremely rare. I've never seen anybody have a reaction to Rhogam. Of course anything is possible, but it's very, very rare also there's no Thyrosol so it's um, a mercury free preservative that is used. So you can't use mercury preservatives in Rhogam anymore since 2001. So it's very, very safe. So let's look through what pregnancy care will look like when the fetus may be RH positive. Okay. So here's how things will kind of flow for you. So at that first prenatal visit, again, if you're RH negative, you'll get an antibodies screen to see if you have already developed antibodies. And this is important because if you have already developed antibodies, then Rhogam doesn't work.

Dr. Nicole Rankins (24:50): It's not effective. So once alloimmunization, once those antibodies have developed, then Rhogam does not work. It doesn't help prevent things from getting higher. You, you shouldn't get it if you've already developed antibodies. So that's why we look for those antibodies. That's also why prevention is important because once the antibodies are there, they're there and we can't like go backwards. Okay. Now, if you are antibodies screened negative. So you do not have antibodies, which is the case for most people. Then we give Rhogam at 28 weeks. Okay. And then we screen for antibodies again at the same time. So we actually just to keep it simple, do it at the same time, give the Rhogam screen for antibodies. Theoretically, if you do have antibodies, then that Rhogam dose, isn't going to do anything, but the risk are very low. And just to keep it simple for folks, we don't make you like getting an antibodies screen and then come back for the Rhogam.

Dr. Nicole Rankins (25:48): We just kind of do it all at the same time. And you get that single dose of the 300 micrograms of Rhogam, um, at that 28 weeks, okay, now you get that dose. And then the next time you may get it is after delivery. If your baby is D positive and we do need to be careful that you're getting the appropriate dose of the Rhogam after delivery and it needs to be given within 72 hours after birth of an RhD positive newborn, we collect a sample of the cord blood in order to determine the baby's blood type. We also test to make sure that there hasn't been a significant amount of fetal maternal hemorrhage or mixing of the blood, because if it's more than 30 milliliters, then you need, need to get more Rhogam. So we actually test the baby's blood type test and make sure that you're getting enough of the Rhogam.

Dr. Nicole Rankins (26:52): And again, you get that after delivery within 72 hours after birth. Now there are other instances during pregnancy where you may also get Rhogam and I'm just gonna run through those, um, indications then. And those are opportunities when it's possible for blood between mom and baby to mix. All right? So if you have a spontaneous pregnancy loss or a pregnancy termination before 20 weeks, then we are. And when I say before 20 weeks, it's a little bit controversial if you need it before 12 weeks or eight weeks. But in general, if there's any sort of pregnancy loss or pregnancy termination, then you're given the smaller dose of Rhogam. There's no harm in giving the larger dose. It's just overkill. So to speak. So any sort of pregnancy loss or pregnancy termination, less than 20 weeks, then you can get the smaller dose of Rhogam. If you have any sort of prenatal invest invasive testing, like chorionic villus sampling, like amniocentesis, like any sort of fetal surgery, then you would get Rhogam as well.

Dr. Nicole Rankins (28:04): If you have blunt, abdominal trauma, meaning you fell, you were, uh, a victim of intimate partner violence. You were in a motor vehicle action, uh, accident where the airbag deployed directly onto your belly, or you had some sort of abdominal trauma, then we'll give it we'll give it an external cephalic version, we'll give Rhogam. We also give it an ectopic pregnancy. And really anytime that there's a threatened miscarriage in pregnancy where there's any bleeding during pregnancy. And we know that someone is RH negative, typically in the first, in early second trimester, we give it the smaller dose. A lot of places just give the bigger dose just for convenience, but definitely in the second and third trimester, you're gonna get the bigger dose. Now it's unclear when to repeat it, roughly it stays in your system for about three weeks. So if you have an issue, for example, where you have a chronic placenta abruption, and you're having ongoing intermittent bleeding or a subchorionic hematoma, and you're having ongoing intermittent bleeding, it's really not clear what the best, um, repeat strategy is for repeat dosing. So typically we recheck again within three weeks and kind of watch and monitor from there, but that part is not entirely clear.

Dr. Nicole Rankins (29:27): Okay. Now let me talk about a couple of special circumstances surrounding Rhogam administration. What do you do if it was inadvertently ad missed or omitted after delivery or, or say you had bleeding in the second trimester, went into the ER and come to find out they didn't give you Rhogam while you were there and you were RH negative. Well, it should be given as soon as possible. After the recognition of missing, it was recognized. There is some partial protection afforded if it's given within 13 days, some people say within 28 days. So if you didn't get it, when you were supposed to get it, just get it as soon as possible.

Dr. Nicole Rankins (30:12): Also there's some debate as to whether or not, if you know, you're going like a postpartum, permanent sterilization procedure. So for example, you're having a C-section and you know, you're getting your tubes tied at the same time and you know, you're not gonna get pregnant again, actually, speaking of which, if you have your tubes taken out at the time of a C-section, uh, you shouldn't just get them clipped, you should get them completely removed because it reduces the risk of ovarian cancer. But if you know that you are having a permanent sterilization procedure, you know, you're not getting pregnant again, then, then should you even get the Rhogam after birth? Typically, we still give it because sometimes people change their minds or, you know, they try to do a tubal reversal or, or this, that, and the other. So typically we're still gonna give it, but technically if you're not getting pregnant again, you actually don't need it.

Dr. Nicole Rankins (31:04): Okay. And then the final thing I wanna talk about before I talk, uh, end up with hemolytic disease of the newborn is paternal testing. So as I mentioned, the RH status is inherited from mom and dad. So if mom is RH negative, then, and it's, it's, what's called heterozygous or homozygous. So if mom is RH negative, then she doesn't have either one. We could test dad and see if dad is RH negative. And if dad is RH negative, then it's not possible for the baby to be RH positive. So if mom is negative and baby's RH negative, it is not possible for the baby to be RH positive. There is an incidence of roughly 3%, three to 4% where fertility or I should say, paternity is not what we think it is. So we still wanna be careful about that. Obviously, if you're very, very certain of who the father is, and you know, you can ask to have the father checked.

Dr. Nicole Rankins (32:08): And if again, dad is RH negative, then it's not possible for the baby to be RH negative or RH positive. And then in that instance, then you do not need Rhogam. Okay. So let me say that again, cuz I feel like that was a little bit like tongue tied. If mom is RH negative, you test dad and dad is RH negative. It is not possible for baby to be RH positive. And in that case you don't need Rhogam. Now in some places we don't do it in the United States, but some places are using cell-free DNA. So that N I P T test or NIPT test to look and see what the baby's RH type is based on those tests. That is not again being used in the United States, but I can foresee in the future that there is a possibility that that may be used in the future because there is a possibility dad could be RH positive.

Dr. Nicole Rankins (32:58): It's kinda like if you have big D and little D, then dad is gonna be RH positive because of the big D, but maybe dad passed the little D on to baby. So even though dad has the big D and is RH positive, if they passed the little D, then that would make them RH negative. I really want to do like the old school genetic like inheritance thing. Hope you probably know what I'm talking about to explain it. Um, just, but I say all that to say that there probably will be a role in the future for those N I P T tests or cell-free DNA tests to determine the baby's blood type and determine for sure whether or not the baby's RH positive or negative. Because again, if the baby is RH negative, uh, then we don't have to do Rhogam, cuz it's not possible to get alloimmunized.

Dr. Nicole Rankins (33:52): All right. Last thing I wanna talk about is hemolytic disease of the newborn. And then also what can you do if alloimmunization has occurred? Okay. So hemolytic disease is a newborn really quickly is when you are RH negative, and you have developed those antibodies, those antibodies cross the placenta and can potentially attack the baby. It doesn't mean that the baby will have hemolytic disease of the newborn. It just means that they are at risk and they need to be monitored closely. And the way that we monitor that is something called ultrasound assessment of wait for it, fetal middle cerebral artery peak systolic velocity. I have no idea who figured that out, but the middle cerebral artery is an artery in the brain of the baby and measuring the peak systolic velocity. Looking at that information gives us a clue as to how severe the anemia is.

Dr. Nicole Rankins (34:52): It's like charts and all this kind of stuff. Okay. And if severe anemia is suspected based on that middle cerebral artery peak systolic velocity, then there needs to be a fetal blood sample in order to determine the baby's hemoglobin. And then depending on the hemoglobin, if you're less than 35 weeks, then you would get potentially an intrauterine fetal transfusion. If you're after 35 weeks, then we would probably just deliver and then treat the baby with the blood transfusion later. So as you can imagine, this is very serious stuff in order to sample the baby's hemoglobin in order to do an intra uterine fetal transfusion. So this really happens in very specialized centers. Not a lot of places do it. It's also another reason why it's really important to prevent it from happening, cuz you don't wanna have to go down this road if you don't have to.

Dr. Nicole Rankins (35:50): Now, the good news is that the transfusions work and as long as the baby can be monitored and get transfusions and doesn't get to anemic, doesn't develop the hydrops and babies do well, but it's a bit of a road to get there. So really the prevention and use of Rhogam during pregnancy is the most appropriate thing to do and causes the least amount of issues and, and, and problems. Now, last thing I will mention is what happens if your first pregnancy you deliver and you do get alloimmunized and you go into your second pregnancy and you have developed antibodies. So what do we do from there? Well, one is that we can just monitor things because again, that intrauterine fetal transfusion is actually very successful. It's complicated, but it's very successful. So things can be monitored and the baby can be transfused if needed some other options.

Dr. Nicole Rankins (36:42): If before you get pregnant, if you know that it happens, then you can be inseminated by sperm from an RH negative donor. There can be in vitro fertilization and pre-implantation genetic testing for RH negative embryos. That means that the father is what's called a heterozygote. Like I talked about like big D and little D if the father has two big D's, then that's not gonna work. Also, you could potentially use a gestational carrier. So your egg and, and dad's sperm and the gestational carrier who, um, is not RH negative, but most of the time we can monitor. It's just, just that the transfusions are complicated ordeal. Okay. So just to recap, all right, the blood group systems are, or the most common one is the ABO system. That's A, B, AB, and O. And whether or not you have those antigens or you don't, and then the positive or negative is RhD positive or RhD negative alloimmunization occurs when you are an RH negative mom and you are carrying an RH positive baby.

Dr. Nicole Rankins (38:01): Some of the baby's blood cells get into your bloodstream. Your immune system recognizes it as foreign attacks, those red blood cells and those antibodies cross the placenta to attack the red blood cells that causes hemolytic disease of the newborn, which can be treated with intrauterine fetal transfusions. If need be the big piece though, is we like to try and prevent it. We screen at the first prenatal visit and we also screen again at 28 weeks and give Rhogam. We also give Rhogam after delivery, since that is the biggest instance of when the mixing of mom and baby's blood can occur. Rhogam is very safe. It works very well. It is not possible to work if alloimmunization has already occurred, Rhogam doesn't work in that instance. So you really want to make sure you prevent it all right. Now, if you want to know about other prenatal tests that are done during pregnancy, then grab my free guide to prenatal test.

Dr. Nicole Rankins (39:05): In this guide, it gives you an overview of all of the recommended tests during pregnancy. It's broken down by trimester. There's a detailed explanation of how and why each test is performed during pregnancy. It allows you to see what's coming up, ask any questions if need need be. You can grab that free guide at drnicolerankins.com/prenatal. All right, so there you have it. Go ahead and share this podcast with a friend. If you love it, sharing is caring and it helps me to reach and serve more pregnant folks. Also be sure to subscribe to the podcast in Apple Podcast or wherever you're listening to me right now. And I would love it if you leave an honest review in Apple Podcast in particular, it helps other women to find the show, helps the show to grow. And I love to hear what you say about the show. So leave me a review there. Do you check out the Birth Preparation Course that's drnicolerankins.com/enroll. It will get you calm, confident, and empowered to have the most beautiful birth. So that's it for this episode do come on back next week and remember that you deserve a beautiful pregnancy and birth.

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