Rh-negative woman during pregnancy, Rh-positive fetus can lead to gestational complications, premature birth, and the defeat of the internal organs of the child. This is due to isoimmunization (sensitization) - maternal antibody generation body, which action is directed to the fetal erythrocytes containing the foreign antigen.
Women with negative Rhesus factor should take into account the risk of erythrocyte incompatibility at conception and proactively take measures to prevent conflict of monkeys.
the possibility of conception
Fetal hematopoietic system begins to form in the second half of the first trimester of gestation. This means that pregnancy complications with a negative Rh factor does not affect the possibility of conception.
Likely to become pregnant at the first attempt is dependent only on the factors affecting ovulation, sperm motility, as well as the compatibility of individual genotypes of the parents.
Before conception is necessary to compare the blood group of the parents, to analyze history for events which could lead to sensitization of the maternal immune system, and nurturing plan based on the results research. Those most at risk are children of mothers with 1 negative group and the father of 2, 3 or 4 positive.
What is the impact on the course of pregnancy
Incompatibility monkey mother and child does not guarantee occurrence of immune conflict. Normally, the blood flow between the fetus and the bearing woman is gematoplatsentarny barrier that prevents mixing of the two kinds of blood and the development of the immune response.
A certain number of red blood cells may enter the child in the mother's body during the period of 8-12 weeks, as at 8 weeks of gestation the fetus hemopoietic system begins to form, and up to 12 weeks generating element gematoplatsentarnogo barrier (placenta) has not yet clear structure.
While carrying her first child in the absence of risk factors for sensitization is rare. This is due to the fact that when exposed to short-M antibody (Ig M) forming a placenta formed which present in the blood in small concentrations, hardly penetrate gematoplatsentarny barrier and do not endanger to the fetus.
For example, if a woman has 2 negative group and 3 in the fetus is positive, then the probability of isoimmunization during the first pregnancy is not high, but there is a risk of incompatible blood group. If the second child is 3 negative group, which is possible due to the dominance of positive Rh factor from the father, the immune response will not affect the second fetus.
Risk factors Rhesus conflict are:
- transfusion of Rh-positive blood in history;
- invasive study of fetal health (chorionic tissue biopsy sampling of umbilical cord blood and amniotic fluid of the fetus);
- occurrence of bleeding due to early detachment of the placenta;
- development of pathologies affecting the integrity of chorionic villi (preeclampsia, diabetes, certain viral infections, including influenza);
- fetal isoimmunization Rh-negative girls at birth from rhesus-positive mothers;
- abortion for more than 8 weeks;
- spontaneous abortion (miscarriage);
- bleeding due to placental damage during separation of placenta or during childbirth;
- hit the cord blood in the mother's body in the process of natural childbirth;
- cesarean section.
In the presence of additional risk factors or repeated pregnancies long lived antibody formation in maternal blood (Ig G), which form permanent immunity. Repeated antigen enters the body D Ig G, having small dimensions, actively released into the blood, penetrate through the placental barrier and provoke the collapse of foreign unborn baby red blood cells (intravascular hemolysis).
Conflict antigen set of red blood cells does not cause specific symptoms in a woman who bears Rh-positive baby. The only sign of conflict can become functional disorders that resemble the flow of late toxicosis. Diagnostic criterion is the presence of antibodies to the D-antigen in the blood of pregnant Rh-negative women.
At the beginning of the early immune response may be observed miscarriages and stillbirths. The risk of gestational complications are women from the first group: even in the absence of the Rh conflict have often observed a group incompatible with the fetus. In group 2 and 3 in a child group of conflict probability is 80%, with 4 - 100%.
The presence of a negative Rh factor in pregnancy affects the list of diagnostic tests and treatments. Diagnosis conflict maternal immunity and erythrocytes of the child comprises the following steps:
- Assay for determination of the concentration (titer) and the class of antibodies to the antigen D. At the first pregnancy and the absence of signs of isoimmunization this study is carried out every 2 months. When harboring these children or there is evidence of sensitization to the 32 weeks analysis of the need to donate each month, at 32-35 weeks - every 2 weeks, 35-40 weeks - every 7 days.
- Fetal ultrasound. Ultrasound fetal diagnosis in suspected rhesus conflict is held 4 times a period of 20-36 weeks of gestation and again - before birth. On US placenta are estimated sizes of internal organs, stomach and fetal body, the amniotic fluid volume, thickness umbilical veins.
- A study of fetal cardiac function (ECG, PCG, CTG). Carrying fonokardiotokografii, CTG and ECG to determine polyhydramnios, disorders of the heart, caused by the swelling of the pericardium, and the degree of hypoxia.
- Samples of amniotic fluid and umbilical cord blood. Amniocentesis and cordocentesis let you explore antirhesus titer Ig G, the degree of maturity of the child's internal organs, the concentration of gall pigment and hemoglobin, blood gases, serum albumin, hematocrit, reticulocyte content and hazardous antibodies in cord blood.
For the prevention and treatment of complications of the immune response of Rh-negative pregnant women are prescribed multiple courses of nonspecific therapy. It includes:
- vitamins;
- Metaboliki;
- mineral complexes with iron and calcium;
- antihistamines.
In parallel with drug treatment is carried oxygen therapy. First supporting rate is assigned to the 10-12 week, the second - in 22-24, and the third - at 32-34. If started early conflict rhesus or critical condition of the fetus of a pregnant blood purification procedure is assigned by antibodies to the D-antigen (plasma exchange).
Pregnant women who are in the group isoimmunization risk RhoGAM immunoglobulin is administered at 28 weeks. If a woman has observed bleeding or conducted sample of amniotic fluid and umbilical cord blood, you may need to repeat injection at 34 weeks.
childbirth Features
Negative blood group women during pregnancy is a risk factor for premature onset of labor. When choosing a method genera physician takes into account the state of the fetus and the maternal antibodies in blood, as holding elective cesarean delivery increases the likelihood of sensitization.
If the mother is Rh negative, but there are no signs of isoimmunization, childbirth carried out according to standard protocol. When a satisfactory condition and the normal development of the fetus is possible to conduct a natural birth sensitized mother for more than 36 weeks.
When the child serious condition recommended Caesarean section for a period not later than 38 weeks. Prior to the cesarean possible intrauterine blood transfusion. Transfusion of blood to the fetus can reduce the hypoxia and prevent late miscarriage.
Immediately after birth, children with severe complications rhesus conflict, exchange transfusion of red blood cells of group 1, plasma or blood group with Rhesus negative. This is due to the fact that the blood of a newborn still present Rh antibodies, which came to him from the woman's blood.
Children with blood group 4 are universal recipients (recipients), so that in the absence of the desired biomaterial allowed transfuse blood from any group of Rhesus negative.
Within 14 days after birth with signs of anemia is forbidden to breastfeed.
In the absence of disease breastfeeding can begin immediately after the injection of specific immunoglobulin which destroys Rh-positive red blood cells in maternal blood, ceasing the production of antibodies.
Impact on the child
The combination of negative blood group and pregnancy, Rh-positive fetus is not dangerous for the mother's body.
For a child the consequences of sensitization heavier, because IgG antibodies are targeted its erythrocytes - red blood cells are responsible for the blood oxygen content.
As a result of constant development of antibodies in the child develops hemolytic disease of newborn, which characterized by a sharp decrease in the number of erythrocytes, the presence of hypoxia (oxygen deficiency in the tissue) and other complications. In the internal organs of the child accumulated bilirubin - bile pigment, which is a metabolic product of hemoglobin from erythrocytes destroyed. This same pigment causes fetal CNS intoxication or so-called "Kernicterus".
Availability conflict group (e.g., a positive third group of fetal and maternal second negative blood group) during pregnancy provokes more active decay of erythrocytes and aggravation intoxication.
The consequences of Rh-conflict for the child are not only at a high risk of death soon after birth, but the defeat of the internal organs and the central nervous system. Early bilirubin toxicity and the negative impact that has isoimmunization of pregnancy, may cause hearing loss and gaps in child physical and mental development.
The likelihood of conflict indicators
The likelihood of conflict monkeys mother and fetus is determined by the combination of genotypes of the parents.
The genotype of the child consists of a pair of haplotypes, one of which is taken from the mother, and the second - his father. Each of haplotypes may carry information about the presence or absence of antigenic determinants. The presence of antigen (D) on the surface of erythrocytes is a dominant trait, and its absence (d) - recessive, so the heterozygous genotype of the fetus (Dd) of its status is Rh-positive.
Rh-negative mother of the child is always homozygous genotype (dd).
Risk of Rhesus-conflict (Rh inheritance scheme)
| Antigen status of mother and father | Father Rh (-) | Father Rh (+) (heterozygote) | Father Rh (+) |
| Mother Rh (-) | Child Rh (-). Immune conflict is excluded. | Child Rh (-) (50%) or Rh (+) (50%). Isoimmunization possible. | Child Rh (+). Rhesus conflict is possible. |
| Mother Rh (+) (heterozygote) | Child Rh (-) (50%) or Rh (+) (50%). Isoimmunization excluded. |
Child Rh (-) (25%) or Rh (+) DD or Dd (75%). Isoimmunization excluded. |
Child Rh (+) or Dd. The immune response is excluded. |
| Mother Rh (+) | Child Rh (+). The conflict is excluded. |
Child Rh (+). The immune response is excluded. |
Conception on the partner with the opposite rhesus not always provokes rhesus incompatibility. For example, pregnancy, with 3 negative blood type from the father of the same, but Rh-positive group, can lead to the birth of a Rhesus-negative child, who inherited the recessive sign.
Group incompatibility is less dangerous for the health of the fetus, but can aggravate disorders caused by Rhesus conflict. groups characteristic determined by the presence agglutinin (α, β) in plasma and agglutinogens (A, B) on erythrocytes and their compatibility - only the presence of agglutinogens.
Blood first group comprises only agglutinins, second and third - one agglutinogen, fourth - only agglutinogens.
For example, a negative third group that is defined in the agglutinogens, compatible with a group in which It presents a similar marker (In (III) α) or groups which lack opposite agglutinogen (0 (I) αβ, In (III) α).
The combination of the second, third and fourth positive group with the first negative group threatens the development of the conflict.
Gestation at 2 and 3, the group does not cause complications if the child erythrocytes no specific agglutinogens or set of relevant antigens characteristic of matter. The presence of Rh fourth group (-) in the mother can cause rhesus incompatibility, but excludes the conflict group.
