In every human chromosome is a collection of genes. The latter are hereditary characteristics. Moreover, the formation of the genotype directly depends on the adaptation mechanisms. However, not only certain appearance features and survival skills in this or that environment are transmitted to children by inheritance. Offspring can get a predisposition to certain diseases. Blood parameters are also inherited. A few years ago, doctors believed that a Rh-negative child could not be born to Rh-positive parents. However, this statement turned out to be a myth. Rhesus-positive parents have a small probability of having a baby with negative Rhesus, but there is one. In this case, doctors even during pregnancy take all possible measures to prevent a conflict between the mother and the fetus.
Rhesus factor: concept
The International Society of Transfusiologists has recognized several blood group systems. The most clinically significant are two. According to the first, there are only 4 blood groups. At the same time, there are concepts of universal donors and recipients.
According to the second, the entire population of the globe is divided into two groups. Most of them (approximately 85%) are Rh-positive.
Rhesus factor is a protein compound located on the surface of red blood cells. A larger population has it, while some people do not. In the latter case, it is customary to say that the blood has a negative Rh factor.
This indicator does not in any way affect the state of health. It is relevant only during pregnancy, transfusion of liquid connective tissue or its components, as well as when transplanting a donor organ to a recipient.
This indicator is inherited. But it also happens that a child is born with negative Rhesus in positive parents.
Laws of inheritance
Genes are transmitted from parents to offspring that contain information regarding the presence of a protein compound on the surface of red blood cells. Rhesus factor is a dominant feature. In other words, if at least one parent has one, he will also appear in the child.
But, according to statistics, only 75% of children whose mother and father have a positive Rh factor have a protein compound. The rest of the kids do not have it. In other words, despite the laws of inheritance, a Rh-negative child may be born to Rh-positive parents. In this case, it is customary to talk about the presence of a gene in the mother or father that is responsible for both the presence and absence of protein.
Probability of conflict
The table below provides information on what Rhesus factor a child may have. In addition, the probability of a conflict between the mother and the fetus during pregnancy is indicated.
| Presence / absence of protein in the father | The presence / absence of protein in the mother | What will be the Rhesus factor in a child, the probability | Conflict, Probability |
| Is available | Is available | 75% "+", 25% "-" | Is absent |
| Is available | Is absent | 50% "+", 50% "-" | Available, 50% |
| Is absent | Is available | 50% "+", 50% "-" | Is absent |
| Is absent | Is absent | 100% "-" | Is absent |
As can be seen from the table, a child with a negative Rh factor can be born to positive parents. However, a few years ago, doctors believed that this was impossible.
Parents have a positive Rhesus, a child has a negative Rh - why?
As mentioned above, children receive a certain set of genetic information. In most cases, the presence of a protein compound on the surface of red blood cells is inherited. However, in practice, situations arise when both parents are Rh-positive and the child is negative.
This is completely normal. It indicates the presence of a particular gene. In this case, it is enough to find out from the relatives (and not necessarily only the nearest ones) what Rh factor they have. Surely among family members there is one in the body of which there is no protein.
Parents have negative blood, and the child has positive blood
In this case, you can begin to rapidly sort out the relationship. The situation when both the father and the mother have a positive Rhesus, and the child is negative, is acceptable. But if parents do not have protein on the surface of red blood cells, then in children it will not appear with a 100% guarantee. And in this case, it makes absolutely no sense to look for relatives with a positive Rhesus factor.
Danger of conflict between mother and fetus
Immunological incompatibility can occur both during pregnancy and during delivery. According to statistics, Rh conflict is more often diagnosed in women who have a second, third, etc. baby.
During the first pregnancy, it can occur for the following reasons:
- In the past, the future mother was transfused with liquid connective tissue or its components. But during the transfusion, the Rh factor was not taken into account.
- Artificial or natural abortions in the past.
If a positive father and a negative mother have a baby with a negative Rh factor, the conflict will occur during the next gestation. This is due to the penetration of the umbilical cord connective tissue into the maternal bloodstream during delivery.
The likelihood of sensitization of a woman's body also increases after:
- Caesarean section.
- Bleeding developed during pregnancy.
- Damage or detachment of the placenta, as well as after its separation by hand.
- Amniocentesis.
- Chorionic Biopsies.
If during pregnancy it turned out that Rh-positive parents have a Rh-negative child, you should not panic. It is recommended to re-submit the blood for analysis in order to exclude the likelihood of an error (in the middle of the 20th century, the blood group and rhesus were often incorrectly determined) and if there is a conflict, it should be detected in a timely manner. Ignoring the latter leads to the development of hemolytic disease in the baby. It is accompanied by an increase in size and impaired functioning of the following organs:
- The liver.
- Brain.
- Heart muscle.
- Spleen.
- Kidney.
In addition, the fetus can be diagnosed with toxic damage to the central nervous system, better known as bilirubin encephalopathy.
As a rule, the absence of medical intervention leads to miscarriage, stillbirth, or fetal death. There is a likelihood that a child will be born, but in this case, all kinds of hemolytic disease are diagnosed in infants.
Rhesus conflict is not accompanied by the occurrence of any disturbing symptoms in women. Sometimes functional disorders characteristic of gestosis appear.
If in the event of a conflict a Rh-negative child was born, the baby is immediately examined for signs of hemolytic disease.
Symptoms of pathology in infants:
- Anemia.
- Hypoxia
- An increase in the size of internal organs, especially the liver and spleen.
- The presence of immature red blood cells in the blood.
Even after giving birth, you should not relax. Ignoring the conflict during pregnancy in the future can turn into serious complications for the baby, in particular, and death.
What can be done during gestation?
Women at 10, 22 and 32 weeks must undergo a course of desensitizing therapy. The treatment regimen includes vitamins, metabolites, antihistamines, iron and calcium preparations. In addition, pregnant women are shown ozone therapy.
If the gestational age exceeds 36 weeks, self-delivery is permissible. But only on condition of well-being of both mother and fetus. In severe cases, a cesarean section is performed.
In order to prolong pregnancy, intrauterine blood transfusion via the umbilical vein can be prescribed.
Doctors opinions
Currently, experts do not question the fact that the child may have a negative Rhesus. Why it happened, if the mother and father are positive, parents need to understand. If we are not talking about adultery, you need to ask relatives. As a rule, a person with a negative Rhesus is in the family.
This situation is associated with certain risks. In order to prevent the full development of the Rh conflict, a woman should regularly visit the attending physician and undergo all the necessary diagnostic procedures. If danger is found for the baby, it is necessary to strictly follow the instructions of a specialist.
What research needs to be done:
- A blood test during which the class and titer of anti-Rhesus antibodies in the fluid connective tissue are determined. You need to donate blood every month for up to 32 weeks, then every 14 days.
- Ultrasound of the fetus.
- Cardiotocography.
- Phono- and electrocardiography.
If necessary, a study of amniotic fluid may be prescribed. However, amniocentesis is a procedure associated with certain risks. Doing it without emergency is not recommended by doctors.
Finally
The Rh factor is a specific protein compound that is located on the surface of the red blood elements - red blood cells. A larger population of the globe (75%) has it. The rest have no protein compound in the blood. Rhesus factor is a dominant feature. It is part of the human genotype and, accordingly, is inherited. However, in practice, there are cases when a Rh-positive child is born to Rh-positive parents. This situation is a variant of the norm, it is detected even during pregnancy. But during the gestation period, it is important to undergo a comprehensive diagnosis in order to timely detect possible pathological conditions.