ABO blood type incompatibility between mother and child
Introduction
Mother and child ABO blood group incompatibility Maternal and child blood group incompatibility is the same type of immunity (isoimmunization) caused by blood type discord between pregnant women and fetuses. In 1938, Darrow recognized that fetal blood is the causative antigen. The blood type antigen obtained by the father's inheritance is just missing from the mother. This antigen enters the mother through the placenta, causing the mother to undergo allogeneic immunity. The produced antibodies pass through the placenta and enter the fetus, causing the fetus and the newborn to destroy red blood cells. Hemolytic disease, such hemolytic disease occurs only in the fetus and early neonates, and is a very important cause of hemolytic disease in newborns. The cause is related to immunity and heredity, so that several consecutive fetuses can get sick. The disease has no adverse effects on pregnant women, and the fetus and newborn may die due to severe anemia, or a large amount of bilirubin produced by hemolysis may infiltrate into brain tissue to cause bilirubin encephalopathy. ABO blood group incompatibility is the main cause of hemolytic disease in newborns in China, accounting for 96%, and is also a common cause of hyperbilirubinemia, accounting for 28.6%. Foreign statistics ABO blood type does not account for 15% of births, and 3% of clinical symptoms. China's statistical ABO blood group incompatibility accounted for 27.7% of the total number of births, of which 20% of the incidence, 5% of clinical symptoms, the National Neonatal Jaundice Conference held in June 1995, the paper on hyperbilirubinemia 23 A total of 68 provinces and cities, a total of about 11610 patients. basic knowledge The proportion of sickness: 0.01% Susceptible people: infants and young children Mode of transmission: mother-to-child transmission Complications: neonatal bilirubin encephalopathy
Cause
Mother and child ABO blood group incompatibility
Causes
ABO blood group incompatibility is the main cause of hemolytic disease in newborns in China, accounting for 96%, and is also a common cause of hyperbilirubinemia, accounting for 28.6%. Foreign statistics ABO blood type does not account for 15% of births, and 3% of clinical symptoms. China's statistical ABO blood group incompatibility accounted for 27.7% of the total number of births, of which 20% of the incidence, 5% of clinical symptoms, the National Neonatal Jaundice Conference held in June 1995, the paper on hyperbilirubinemia 23 A total of 68 provinces and cities, a total of about 11610 patients.
From the etiology of hemolysis or as the second (17) or the third (18), so it seems that hemolysis is a common cause, and the ABO blood group does not occupy the first place in hemolysis, the domestic literature since 1994 There are many articles on serum analysis of neonatal hemolytic disease. These are published by blood transfusion magazines, etc., and the number is large. Among them, there are mainly 4 pregnant women, a total of 5,971 people, in which O~A 2277 people do not fit, 1858 people who do not fit O~B, the former is 1.22 times the latter. They also have anti-A anti-B antibody titer. The titer of neonatal hemolytic disease is higher than 1:128. Higher, so the antibody titer is related to the occurrence of the disease and clinical strategies.
The first child's disease accounts for 40% to 50% of the disease, because women with type O are often stimulated by other causes before pregnancy [such as intestinal parasite infection, injection of typhoid vaccine, tetanus or diphtheria, they have A And (or) B blood type substances, some plants also have A, B blood type substances] so that the body produces IgG anti-A, anti-B antibodies, such antibodies can cause hemolysis after entering the fetus through the placenta after pregnancy, although maternal ABO blood group incompatibility It is very common, but there is much less AB0 blood group incompatibility, because: 1 IgG anti-A or anti-B antibody enters the fetus through the placenta, neutralized by blood group substances, and the adsorbed part of the tissue cells are treated. 2 Fetal erythrocyte A or B antigenic sites are few, only 1/4 of adults, antigenicity is weaker than adults, and the reaction ability is poor, so the incidence is less.
In the ABO blood group system, the pregnant women are mostly O-type, and the father and fetus are A, B or AB type. The fetal A and B antigens are sources of sensitization. There are 6 antigens in Rh blood type, which are C, c, D, d, E, and e, respectively. The hemolysis rate is the highest, so it is clinically tested with anti-D serum. When the mother or newborn erythrocytes are agglutinated with known anti-D sera, they are Rh positive, and vice versa. Rh-negative pregnant women can occasionally be sensitized by other antigens to produce antibodies, such as anti-E anti-C antibodies, etc., resulting in maternal and child blood group incompatibility.
Fetal red blood cells can not pass through the placenta. Only when the placenta is damaged during pregnancy or childbirth, the fetal red blood cells in the villus can enter the mother's body. According to the amount of entry and the number of sensitization, it affects the amount of antibody produced and finally causes the hemolysis of the baby. Wait.
Prevention
Mother and child ABO blood group incompatibility prevention
The onset of hemolytic disease requires the mother to contact the antigen twice in order to produce a sufficient amount of antibody to cause the fetus to be affected. First, understand how the pregnant woman is sensitized. When the mother is Rh negative, the fetal Rh-positive red blood cells are mainly in the process of childbirth. In the pregnancy, the fetal red blood cells enter the mother through the placenta during pregnancy, but the chances are small and the number is small. The Rh-positive red blood cells entering the mother gradually gather in the spleen and are swallowed by the phagocytic cells, but it takes a long time. Release enough Rh antigen, stimulate immune-active cells to produce antibodies, start to produce antibodies that are IgM, can not pass through the placenta, but soon produce IgG antibodies, can pass the placenta to the fetus, the first time the antibody is produced at a slow rate, a small number, and After a period of time, the growth stops, but the immune memory cells appear at the same time as the antibody is produced, and it persists. The whole process takes at least 8 to 9 weeks or 6 months, at which time the woman has been sensitized.
Once sensitized, it can no longer return to the unsensitized state. When the woman re-pregnant Rh-positive fetus for the second time, the antigen re-enters the mother and causes a strong reaction. At this time, the antibody is produced at a high speed and a large number. It occurs mostly during the second pregnancy and delivery, that is, the mother needs secondary exposure to the antigen to cause hemolytic disease in the newborn. Therefore, prevention of sensitization in Rh-negative women must be carried out immediately after the first delivery of Rh-positive newborns. Therefore, anti-D globulin should be injected when the first exposure to Rh is positive, and anti-Rh(D) IgG 300 g is intramuscularly injected within 72 hours after the first birth of Rh-positive newborn, and the anti-Rh(D) IgG dose is transfused during transfusion. Can be calculated according to 20g / ml blood, prenatal preventive dose is generally recommended 300g, if abortion, gestational age less than 12 weeks injection 50g, >12 weeks injection 100g, 28 weeks 200g, and then completely neutralized per milliliter of fetal blood to be injected Anti-D antibody 10 ~ 25g calculated to obtain the appropriate dose, for non-sensitized Rh-negative women, can add Rhogam 300g at 28 weeks of gestation, and add 300g 72h after delivery of Rh-positive newborns, have a history of ABO hemolytic disease Pregnant woman, using blood circulation to remove phlegm Some preventive effects can be achieved.
Complication
Mother and child ABO blood group incompatibility complications Complications neonatal bilirubin encephalopathy
Severe complication of bilirubin encephalopathy should be given early and active treatment.
Symptom
ABO blood group incompatibility between mother and child Common symptoms Dead fetus heart enlarges severe jaundice immune hemolytic physiology jaundice severe anemia jaundice cord blood erythrocytosis hemolytic anemia
The symptoms of ABO hemolytic disease vary greatly. Most of the symptoms are not serious. The earliest symptom is jaundice, which usually appears within 24 to 48 hours after birth, and disappears within 3 to 7 days. It is easily regarded as physiological jaundice and missed diagnosis. Only in the late stage of anemia, severe cases can occur stillbirth, severe jaundice, or severe anemia, but compared with Rh hemolytic disease, whether it is the degree of jaundice, anemia, liver and spleen size and incidence of bilirubin encephalopathy are relatively light.
Examine
Mother and child ABO blood group incompatibility check
1. Blood type pregnant women and husbands should be tested for blood type.
2. Pregnant women with serological tests are positive.
3. Neonatal serological examination to take cord blood: 1 Coombs test positive. 2 antibody release test. 3 free antibody test.
4. B-check.
5. Amniocentesis check.
Diagnosis
Diagnosis and differentiation of mother and child ABO blood group incompatibility
Pregnancy diagnosis
(1) Medical history: In the past, there were stillbirths, miscarriage, premature birth or rapid death after birth or bilirubin encephalopathy within 24 to 36 hours after birth. It should be thought of and suspected to have maternal and child blood group incompatibility, and should be further an examination.
(2) blood type examination: pregnant women and their husbands must do blood type examination, such as husband is type A, type B or type AB and pregnant women are type O, may occur ABO blood group incompatibility, such as husband is Rh positive, pregnant women are Rh negative, Rh blood group incompatibility may occur. When neonatal hemolytic disease occurs, ABO and Rh blood type identification should be performed on the mother and child respectively. The typical Rh hemolytic disease, the mother and child ABO blood type are often the same, the mother is Rh negative, the child is Rh positive, sometimes due to Too many anti-D antibodies, almost all of the neonatal red blood cells covered, may incorrectly identify Rh-positive red blood cells as Rh negative, newborn father is Rh-positive, if the mother and child D antigenicity is the same, should pay attention to whether it is other antigens in the Rh system ( Such as E, C or c, etc. or other rare immune hemolytic anemia caused by rare blood group antigens.
(3) Antibody detection: If the pregnant woman is positive for serology, it indicates that it has been sensitized. The IgG antibody titer should be measured regularly, 28 to 32 weeks of pregnancy, once every 2 weeks; once every week for 32 weeks or more. , Rh blood group incompatibility IgG antibody titer> 1:32, ABO blood group incompatibility IgG anti-A (B) titer > 1:128, fetal hemolytic disease may occur, however, antibody titer is only for reference, due to high titers and fetal The incidence of the baby and the severity of the disease are not necessarily proportional, because the occurrence of hemolytic disease depends on the barrier effect of the placenta on antibody permeability; the protective mechanism of the fetus, that is, the tolerance of the fetus to hemolytic disease.
1 pregnant women serological diagnosis method: take pregnant women blood 6ml (5ml self-coagulation, 1ml anti-coagulation), another husband's blood 2ml, added to the anti-coagulation tube, when the mother and child blood type is not combined, the serum antibodies are completely and incomplete The latter can enter the fetus through the placenta, so the determination of incomplete antibodies and their titers in the serum of pregnant women has clinical practical significance for estimating fetal conditions.
A. Saline agglutination test: Check whether serum contains complete antibody (IgM), and serum complete antibody and red blood cell antigen are agglutinated in physiological saline.
B. Colloidal medium test: Check whether the serum contains incomplete antibodies (IgG), and serum incomplete antibodies and red blood cell antigens are agglutinated in the colloidal medium.
C. Papaya enzyme test: After treatment of red blood cells with papain, and then combined with serum incomplete antibodies, agglutination can occur in physiological saline.
D. Direct or indirect anti-human globulin test (Coomb test): Any red blood cell with surface-bound incomplete antibody is called sensitized red blood cell. Human globulin is an antigen used to immunize animals to produce anti-human globulin serum. The human globulin serum can specifically agglutinate with the globulin antigen on the surface of the sensitized red blood cells, and the direct method is used to detect the presence or absence of IgG antibody adsorption on the red blood cells of the newborn, that is, whether the red blood cells have been sensitized; It is used to detect the presence or absence of IgG antibodies in the serum of pregnant women. If there is agglutination, it is positive, and then the serum is diluted by multiples, and the antibody titer is obtained from the maximum dilution factor at which agglutination occurs.
2 neonatal serological examination: take 6ml of cord blood, of which 5ml without anticoagulant, 1ml plus anticoagulant, for the following three tests:
A. Direct Coomb test.
B. Antibody release test, this method is to solve the problem of occlusion of red blood cells in children, and release the test to make the Rh antigen on the red blood cells of the newborn release the parent IgG antibody, so as to correctly identify the Rh blood type of the child.
C. Free antibody test, using standard red blood cells to detect the presence or absence of free IgG antibodies in the serum.
(4) B-mode ultrasound examination: If the fetus has severe hemolysis, B-mode ultrasonography can show the typical edema state, fetal fluid in the abdominal cavity and thoracic cavity; double aura (scalp edema) in the fetal head, heart enlargement, liver and spleen Large; placental parenchyma has very little light spot (placental edema thickened and large), but mild hemolysis, there is no typical performance above.
(5) Amniocentesis: amniotic fluid was taken under B-ultrasound, and the absorbance of bilirubin in amniotic fluid was analyzed by spectrophotometer. The absorbance difference of bilirubin at 450nm (OD450), >0.06 is the dangerous value, 0.03~0.06 is the warning. Value, <0.03 is a safe value, and can also measure bilirubin content. The normal value of bilirubin above 36 weeks of pregnancy is 0.513~1.026mol/L (0.03~0.06mg/dl), such as increased to 3.42mol/L (0.2 Mg/dl), indicating that the fetus has severe hemolysis.
1 indication of amniocentesis: indications should be strictly controlled, in the past there is a history of neonatal hemolysis, and the pregnant woman's antibody titer is high, then check the bilirubin content in amniotic fluid, can understand the hemolysis of the fetus Degree, in order to take timely measures, amniocentesis time, usually begin at 30 to 32 weeks of gestation, repeat every 2 weeks if necessary, early on the onset of neonatal hemolytic disease or early stillbirth, may also be appropriate Amniocentesis can usually be performed during the first 4 weeks of the gestational week of the previous termination of pregnancy.
2 Relationship between bilirubin content in amniotic fluid and fetal condition: Liley based on hundreds of amniotic fluid bilirubin measurements, the relationship between bilirubin optical density and gestational age in amniotic fluid is shown. The map is divided into three zones, and then the amniotic fluid is The optical density reading at 450 nm, minus the baseline optical density reading, falls on the corresponding gestational age of the semi-logarithmic table, with little or no disease in the first zone, in the second zone or close to the third zone. In the zone, it is moderate to neonatal hemolysis. In the third zone, the fetus has severe hemolysis. For example, in the near future (7 days), the pregnancy is likely to die. Some people think that the diagnostic accuracy is 94.4%, but one measurement. Insufficient to rely on, should repeat the puncture within a few days, if the high value does not change or continue to rise, suggesting a strong diagnostic reliability.
3 attention of amniocentesis: First, place the placenta under B-ultrasound, try to avoid placental puncture, to reduce the fetal, unnecessary maternal bleeding, such as the mixed amniotic fluid mixed with blood, can affect the correctness of the test results Because the bilirubin content in the fetal blood is 25 times larger than that in the amniotic fluid, the puncture should be accurate. After the amniotic fluid is taken out, it should be placed in a brown vial or a test tube wrapped in black paper or tin foil to reduce or avoid light. If the amniotic fluid is dark yellow, suggesting that the bilirubin content is high, appropriate measures should be taken.
(6) rare blood type incompatibility diagnosis: rare blood group incompatibility diagnosis of neonatal hemolytic disease must meet the following conditions: 1 neonatal Coomb test positive and hemolytic anemia. 2 mother and child Rh and ABO blood type match. 3 mother Coomb test negative, can exclude neonatal hemolytic disease caused by autoimmune antibodies. 4 neonatal serum or red blood cells release IgG antibodies against their own rare blood group antigens, such as the fourth unconditional examination, based on the clinical manifestations of neonatal hemolytic disease, plus the first three items, can also be pre-diagnosed as rare blood group antigen The resulting neonatal hemolytic disease, has been found to cause neonatal hemolytic disease, rare blood types are: Duffy, Kell, Kidd, MNSs, TJa, Lua (rare), Dia and so on.
2. Postpartum diagnosis
For newborns with early onset jaundice, edema, undiagnosed before birth, the main basis for diagnosis after birth is the examination of serum-specific immune antibodies, 1 check the neonatal and maternal blood types to determine the presence or absence of AB0 or Rh Blood type is inconsistent, 2 check whether the baby red blood cells are sensitized, the anti-human globulin test direct method positive indicates that the baby red blood cells are sensitized by blood group antibodies, and can perform a release test to know which kind of Rh blood group antibody, 3 check the presence or absence of baby serum The presence and type of blood group antibodies, in vitro test of infant serum and various standard cells (CCDee, ccDEE, ccDee, Ccdee, ccdEe, ccdee), if the serum of a child and the above standard red blood cells do anti-human globulin Indirect test results CCDee, ccDEE, ccDee, ccdEe group agglutination (positive) and Ccdee, ecdee group negative, it can be judged that the child's serum has no anti-C, anti-c and anti-e antibody, ccDee, ccdEe group positive showed resistance D anti-E antibody, CCDee, ccDEE group agglutination is also related to D, E antigen, 4 check the presence or absence of blood group antibodies in the maternal serum, do indirect anti-human globulin test To confirm.
At the same time, the newborn should do the following tests to determine whether there is neonatal hemolysis: 1 hemoglobin <140g / L (umbilical cord blood), reticulocyte > 6%, nucleated red blood cells > 2% ~ 5%; 2 cord blood bilirubin >51mol/L (3mg/dl), 72h>342mol/L (20mg/dl) after birth, has reached the dangerous value, there is the possibility of hemolysis of the newborn, further observation of the development of jaundice, and take corresponding measures.
In general, ABO blood group incompatibility of jaundice is lighter, anemia is not too serious, red blood cells are spherical, bilirubin less than 205mol / L (12mg / dl) within 72h, Rh blood group incompatibility generally umbilical hemoglobin <140g / L , bilirubin > 68mol / L (4mg / dl), jaundice appeared 24h after birth, severe anemia is obviously pale, or accompanied by heart failure symptoms, nucleated red blood cells increased significantly, up to 20% ~ 100%, clinical symptoms with Hemolysis progresses and worsens, about 25% is due to severe hemolysis and becomes a stillbirth or edema fetus, but sometimes heavy ABO hemolysis is very similar to Rh hemolysis, while light Rh hemolysis is similar to ABO blood group incompatibility, should be distinguished, it is reported that there is still 1% mother The blood type incompatibility is caused by rare blood type. If the mother and child have the same ABO and Rh blood type, and the newborn has early jaundice, and the Coomb test is positive, the blood type caused by the rare blood type should be considered.
Mainly differentiated from Rh hemolytic disease.
