Pregnancy and Rhesus-conflict – a table of Rh factors, possible complications

Pregnancy and Rhesus-conflict - a table of Rh factors, possible complications When registering in a women’s consultation, the future mother is always assigned to conduct a series of tests, including a blood test for the Rh factor. A similar analysis will have to be handed over to the Pope. Moreover, the result of my father’s analysis of the most important …

content of the article:

  1. Causes of Rh sensitization and gestational
  2. The mechanism of Rh-conflict
  3. Symptoms of Rhesus-conflict and complications

Causes of rhesus sensitization during pregnancy – at what time does it occur?

The term “rhesus” is used to refer to a complex consisting of 50 specific antigens that are located on erythrocytes.

The most important among all groups of antigens are the proteins of group D, considered by specialists at the time of determination of the rhesus of a future mother.

Most of the world’s people have a positive Rh factor, confirmed by the content of their D-antigen (note – Rh +). In the blood, the remaining 15% of this antigen is not present, and their blood is Rh-negative (note Rh-).

In normal life, Rh-negative blood is not a sentence – and, in general, does not affect life at all.

But here at pregnancy or in case of a blood transfusion the negative such feature is capable to deliver many problems.

Pregnancy and Rhesus-conflict - a table of Rh factors, possible complications


When using the terms “positive” or “negative” Rh factor, only the presence or absence of D-antigen (despite the presence of other groups of proteins) is implied.

Rhesus factor in different peoples

  • As statistics show, 85% of Europeans have Rh-positive blood.
  • But in Asia and India, this percentage is much higher – it reaches 99%.
  • In the Basques (note – the nationality in Spain), a negative rhesus will be in a third of the population.
  • A black inhabitants of the earth have Rh-negative blood in only 7% of cases.

Video: Pregnancy and Rhesus Conflict: Risks for Mom and Baby

What is Rhesus Sensitization?

This diagnosis is usually made by a specialist after identifying the Rh antibodies in the maternal blood.

It is clear from the title that Rh antibodies arise as a “protest” for foreign red blood cells. Compounds of the protein structure in the mother’s blood, with its negative Rhesus factor, are formed when the “alien” Rh-positive children’s erythrocytes enter the body.

That is, the mother’s immune system refuses to accept other’s red blood cells, as her own, resulting in a Rhesus-conflict, called sensitization.

The development of Rh-conflict is impossible if the baby with negative rhesus lives in Rh-negative mother. Conflict occurs solely when the sensitivity of the mother’s body to a particular agent is increased.

Not dangerous for the mother herself, sensitization can cause miscarriage or (which often happens) the development of hemolytic disease of the crumbs.


  1. Rhesus factor of the baby does not matter if the mother’s blood is Rh-positive.
  2. Sensitization can not be feared if the rhesus is negative in mom and baby.

What are the causes of Rh-conflict?

The key reasons are …

  • Births.
  • Blood transfusion.
  • Miscarriage or abortion.
  • Manipulation of an invasive nature during pregnancy.
  • Ectopic pregnancy .

To put it more simply, any situation in which the fetus and mother’s blood is mixed, can lead to the formation of Rh-conflict.

That’s why the experts categorically do not recommend young mothers with Rh-negative blood to interrupt the first pregnancy, which, in most cases, mothers endure without problems (the second pregnancy accounts for a high percentage of Rh-conflicts).

But after the abortion of the Rh-negative mother of the 2nd pregnancy may simply not happen.

At what time can Rhesus conflict arise?

Usually this pathology begins to manifest itself already from the 6th to 8th week of fetal development – when D-protein appears on the erythrocytes of crumbs.

That is why the determination of the content of antibodies in maternal blood is done regularly (monthly), from the moment of registration.


The change in the Rh factor during pregnancy is impossible because the protein is inherited genetically and remains unchanged until the end of life. The mechanism of development of Rh rhesus-conflict in pregnancy is a table of probability according to the Rh factors of parents and the child

Rh-factor is transferred to the fetus together with the daddy’s genes. It is the father who is responsible for what will be the rhesus of the baby.

For every man, control of the D-protein is carried out by genes that are located in a pair of chromosomes.

  1. In case of dominant genes (in 45% of cases) a man has Rh-positive blood. In such a man, children will always be Rh-positive.
  2. In the case where there is a dominant gene in one papal chromosome and the other is recessive (in 55% of cases), only 50% of the cases will be born with a Rh-positive baby.

Given that it is extremely difficult to determine genes in advance, these studies are carried out only in case of acute necessity (for example, with IVF procedure ).

Predicting the Rh baby is impossible. The possibility of the appearance of crumbs with a negative rhesus varies from 25 to 75 percent in the case of different parental rhesus.

But it is important to remember that for the 1st pregnancy, Rh-conflict is possible only in 5% of all cases. During this first pregnancy, there is no mixing of the blood of the mother and baby, so the Rhesus conflict is a rare occurrence.

The risk rises only when Rh-negative blood of the Rh-positive red blood cells of the baby gets into the mother’s body …

  • With increased permeability of the placental vessels.
  • When gestosis, with the threat of miscarriage or with diseases that can disrupt the integrity of the blood vessels of the placenta.
  • For diagnostic procedures that can lead to a mingling of the blood of the mother and fetus.
  • For childbirth and caesarean section.
  • In the case of manual removal of the placenta or with its early detachment.
  • In case of surgery (ectopic, miscarriage, abortion).

After the first penetration of foreign proteins into the mother’s blood, the synthesis of IgM class antibodies occurs. But the molecule has a large size, and to get into the fetal blood flow is incapable – as a result, the most severe complication (in most cases) is premature birth.

What happens with the second pregnancy?

By the second pregnancy, the mother of the Rh-negative organism is already familiar with the positive Rh factor, and repeated contact with it is the reason for the rapid development of a serious number of much smaller IgG antibodies, which already freely penetrate the baby through the placental vessels, causing the aforementioned consequences.

For the sake of justice (and the tranquility of expectant mothers) it is worth noting that Rhesus conflict can be avoided – even if the rhesus mothers and crumbs do not coincide, with the competent observation of the future mother by professional specialists.

What is the likelihood of Rh-conflict mother and fetus – table

Mom (Rh +) + Dad (Rh +)

Rhesus kid 75% Rh + / 25% Rh

There is no conflict probability

Mom ( Rh- ) + dad ( Rh +)

Rhesus baby 50% Rh + / 50% Rh

probability of conflict is 50%

Mom (Rh +) + dad (Rh-)

Rhesus kid 50% Rh + / 50% Rh

There is no conflict probability

Mom (Rh-) + dad (Rh-)

Rhesus kid 100% Rh

Probability there is no conflict

Symptoms Rh-conflict pregnancy – potential complications for mother and fetus

There are no specific symptoms, which could be defined – or at least suspect – an expectant mother’s Rh conflict, simply does not exist. In addition, this phenomenon has absolutely no effect on her health.

In a word, problem identification is possible only with the examination.

  • Blood test for antibodies . If the norm of the credits is exceeded, the doctors speak about the development of Rh-conflict.
  • ultrasound. This procedure with Rh-conflict will show an increase in the internal organs of the fetus in size, as a consequence of hemolysis of red blood cells. Also, doctors look at the presence of edema of the fetus, on his posture, the thickness of the placenta.
  • Dopplerography . It will help to assess the quality of the blood flow of the blood vessels of the placenta.
  • Cardiography. It is carried out for the analysis of heart rate.

If there are several symptoms at once, a more thorough examination of the fetus is prescribed to exclude or diagnose hemolytic disease in it.

What is dangerous for Rh syndrome?

As mentioned above, a major danger in the incompatibility of rhesus mummies and crumbs is hemolytic disease, which can threaten both the fetus and the newborn.

In the attack of mother’s antibodies on the fetal erythrocytes, the second quickly destroy, resulting in anemia, organ enlargement, placenta thickening, hypoxia and so on.

The severity of the consequence of the Rhesus conflict for crumbs will depend on the duration of isoimmunization, on the viability of the fetus itself and on the activity of producing the necessary antiresusive immunoglobulins in the mother’s blood.

Pregnancy. What should I do if a woman has a negative Rh factor?

This article will in no way replace the relationship between the doctor and the patient. It is informative, and is not a guide for self-treatment and diagnosis.

Site recalls that in all dubious health situations it’s never worth to delay or ignore the call to the doctor!

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