Rh negative child of positive parents. How is the Rh factor inherited in humans?
Both my wife and I are Rh-positive, and my son is Rh-negative. Could this be? Nikolai N., Grodno region
Viktor Andreev, Professor of the Department of Medical Biology and General Genetics, GrSMU:
For a long time, people have noted that the child is not an exact copy of the parents. It happens that children have features that are not characteristic of either mother or father.
Many hypotheses have been put forward to explain such observations. The concept of fused heredity has received the widest recognition. According to it, the totality of all the characteristics of each parent is transmitted as a whole to the offspring, in which they mix and lose their individuality.
Supporters of this opinion consider the hereditary substance to be a continuous and precisely divided material. Her symbol is blood. Echoes of this idea are the expressions “purebred”, “half-blood” (in relation to animals), “blood relationship”, “blue blood” that have been preserved since the beginning of the 18th century. The difference between the offspring from father and mother was explained by mixing, and between sisters and brothers - by the variability of the "blood strength" of the parents. The argument in favor of fused heredity is that some traits of the offspring are something in between the traits of the parents. Such a speculative interpretation raises many questions for the spouses to each other.
The founder of the experimentally proven scientific theory of discrete (separate) heredity was Gregor Johann Mendel (1822–1884). The scientist discovered the fundamental laws of inheritance and showed that the factors that are now called genes, the descendant receives from each of the parents.
The gene determines the formation of one elementary trait, while the latter may have several specific manifestations (in genetics - phenes).
For example, the color of the iris is brown or blue; eyelashes - long, short or medium; lips - thin, full or medium fullness; hair is straight or curly. These varieties (versions, states) are called alleles. Of the gene alleles in the human genotype, only 2 can be - from the mother and from the father. Genes do not merge, but when germ cells are formed, they diverge independently of each other. One allele enters one gamete (sperm or egg), and another allele enters the other.
Alleles can be dominant and recessive (from Latin recessus - retreat); the latter do not appear phenotypically in the presence of the dominant allele.
The dominant allele that determines the Rh-positive blood type is Rh; recessive, or hidden, - rh. Allelic pairs of genes are made during fertilization - in the egg there will be one of the possible combinations: RhRh, Rhrh or rhrh.
If both parents have Rh-negative blood (their genotypes are rhrh and rhrh), then a child with Rh-positive cannot be born.
In the case when the mother and father are Rh-positive and their genotypes are homozygous for the dominant allele (RhRh and RhRh), all children will have Rh-positive blood (RhRh genotype).
Since the author of the letter and his wife have a child with Rh-negative blood, then, according to the discrete theory of heredity, the parents are heterozygous by genotype, that is, each has both a dominant and a recessive allele in the genotype (father's genotype is Rhrh; mother's - Rhh). In such a family, a son or daughter can have both Rh-positive and Rh-negative blood.
Let's talk about a situation where the mother's Rh factor is positive, and the father's is negative.
For many people who are far from medicine, the concept: "Rh factor" is familiar only as something associated with blood. And in most cases, they do not need to know the details; in life, this can only come in handy in planning a pregnancy and blood transfusion. In the second option, it is enough to inform the doctors about the blood type and Rh of the victim who will need a transfusion. With planning for children, everything is somewhat more complicated.
Why is the Rh factor important in people's lives, and how does it affect everyone? Many live for decades and have no idea why it is needed. Just a medical word associated with an organism, with a blood type. All. How does it affect pregnancy, why, when the mother's Rh factor is positive, the father's is negative, you need to worry?
What is the Rh factor?
When physicians first began to carefully study human blood and compare it with other fluids, they discovered by experience that when mixing drops of blood from different people, not everything is harmoniously combined. Sometimes, at first glance, two analyzes that are identical, when combined, collapse or precipitate. The microscope and several other studies soon provided answers. Blood began to be divided into groups, then by Rh factors. It turned out that most people have a special protein in it, which plays a role in the functioning of the body. And 15% of the population does not have it! At the same time, they feel good, do not complain. For their blood, the absence of this protein is normal. And when they tried to mix the two samples, they gave a strange reaction. So scientists realized that blood with and without protein cannot interact.
The nature of the mechanism remains a mystery, and science has given it a name. Blood with the presence of protein is called Ph +, and without - Ph-. And people with different Rhesus cannot become donors to each other.
How do blood differences affect pregnancy? Expectant mother with a child of 9 months are together. They are a single organism, and the fetus takes all the nutrients from the mother, giving her everything processed. Takes food, oxygen. But at the same time, each has its own, separate body. The mother's Rh factor is positive, the father's is negative, what will happen and how it affects the development of the fetus, the doctors say during the examination. The development of the Rhesus conflict is a great danger. True, it is high in women who have blood without protein when carrying a child with a "plus" Rh factor.
Consequences of Rh-conflict during pregnancy
Why is there a conflict between different types of blood at all? Expecting a child is a natural process and the mother's body must protect the fetus, nourish it with everything necessary and share its DNA. However, some mechanisms go against the laws of nature. When the Rh factors of the interconnected organisms of the mother with the baby living inside her are different, her blood can perceive the protein that comes to her from the child as a new virus. The defense system operates in a standard way - the danger is studied, then the production of antibodies begins, with which the woman's immunity tries to fight the dangerous, in his opinion, protein, harming the baby.
The consequences entirely depend on the activity of antibody production. The worst are fetal rejection, premature birth, stillbirth. Medium - an attack by the defense system destroys the fetal red blood cells, pulling out and destroying an unfamiliar protein. This prevents the blood of a small organism from circulating, carrying oxygen and nutrients. This causes oxygen starvation, reduced immunity of the crumbs, etc.
Mom is positive, dad is negative.
Knowing the laws of genetics, future parents are usually worried. Should they think about replenishment at all? The mother’s Rh factor is positive, the father’s is negative, the child has about a 50% chance of inheriting either a “plus” from mom or a “minus” from dad. However, doctors are not worried about this alignment. After all, a woman has antibodies in her body. Therefore, even a child with a lack of protein, she takes out calmly. There is simply no reason for the defense system to react - there is no danger.
It happens when both parents do not have protein in their blood. Two "cons". Doctors just shrug their shoulders. The child has nowhere to inherit the "plus", because he takes half the DNA of each parent. Therefore, 100% will be born with a "minus". The pregnancy will go well. The baby then, having matured, will need to carefully choose a partner for himself, especially if a girl is born.
What to do?
Future parents, if they turn to specialists when planning replenishment, explain the importance of the Rh factor and what actions they should take. However, doctors are sure. Even a woman with a rare blood group (AB) and a “negative” Rh factor cannot put an end to the dream of becoming a mother. Achievements in medicine allow specialists to “keep the pulse” throughout the entire pregnancy and correct the work of the immune system of the woman in labor with drugs. And the first child is usually born without problems.
When the mother is Rh positive and the father is Rh negative, natural conception will result in a baby who has a 50% chance of getting the father's Rh factor. But there is nothing to fear.
The procedure for a couple with different Rh factors, when there is no protein in the blood of the father, can differ little from the preparation for replenishment of ordinary spouses:
- a visit to a therapist at a medical center who, having learned about the plans of the couple, writes directions to both;
- visiting a gynecologist and all other specialists whose positions are indicated in the directions;
- passing the necessary tests, one of which will reveal the Rh factors. The specialist will explain to them the importance and future prospects;
- then the mother is prescribed several vaccinations, without revealing serious illnesses, etc.
Often women come to the doctor with a fait accompli, they are future mothers at different times. People are accustomed to little concern about health when the symptoms do not bother. And the preparatory period before planning a replenishment seems to them only physical and moral preparations (diet, a special daily regimen for a woman, the rejection of all bad habits). The couple saves money, plans a place for a future nursery, chooses names. They feel healthy and do not consider it legitimate to consult doctors before planning.
However, also most people may simply not know their blood type. For ordinary life, they do not feel the need for such knowledge. Unless a man served in the army, did not receive a license, a woman too. But, when you are going to become parents, you need to find out what kind of Rh factor your partners have. And when a woman finds herself with a "minus", take double precautions.
The mother's Rh factor is positive, the father's is negative, what the child will have depends on the choice of genetics.
Doctors were often puzzled by the death of patients after transfusions of seemingly ideally matched donated blood. It turned out that the reason for this was the Rh factor - a special protein, or rather, its absence.
In the blood of 85% of the entire population of the globe, this protein is present, and only 15% of people are deprived of it. The name was derived from the rhesus monkey whose blood was used in the experiments.
Rh factor protein is located on the surface of red blood cells -. It does not affect the state of human health, that is, in principle, both a child with the presence of this protein (with positive indicators) and with its absence (with negative indicators) is born healthy.
Problems can arise only when mixing different types of blood.
An organism that has blood with a positive Rh factor, getting blood even of a suitable group, but with a missing protein, is perceived as an alien attack. The activation of immunity begins to fight the "invader", and the so-called arises.
Reasons for the appearance or absence of a special protein in a child
The formation of the Rh factor in a baby is completely controlled by the laws of genetics. If both parents have a positive Rh factor, then a child can be born to them both with the same indicator and without it, that is, with a negative Rh factor. The same condition can appear if the mother has negative blood, and the father has positive blood.
If the fetus inherits the mother's blood, everything will be fine, but the appearance of a positive fetus in a negative mother threatens the development of an Rhesus conflict. If timely measures are not taken, the pregnancy may end in miscarriage, as the mother's body will perceive the fetus as a foreign body. However, if there is knowledge of a possible conflict, this happens extremely rarely, because the blood of the mother and fetus do not normally mix. Only in the presence of various pathologies, the entry of fetal cells into the mother's bloodstream can provoke a negative reaction in which the pregnant woman's body will try to expel the fetus.
Medical techniques make it possible to avoid such complications, to endure and give birth to a normal child.
In most cases, the mixing of the blood of mother and child occurs only at the time of birth and lasts a very short time.So that the baby does not develop hemolytic disease of the newborn, characteristic of the Rhesus conflict, it is immediately placed under special blue lamps.
This prevents the appearance of the negative influence of different blood.In the same case, if both parents are blood-negative, they cannot have a positive child in any way - there is simply nowhere for that very important protein to appear in his blood. So both parents with a negative Rhesus cannot become parents of a child positive for the factor. This is contrary to the laws of nature and our knowledge of human genetics.
A negative Rh factor in a child does not mean that he has any defects or developmental disorders. This is absolutely the same child as having positive blood. It's just that in his body there is no tiny component that will have to be taken into account in the process of his life and development.
Norm or pathology
A negative Rh factor in a child is not a pathology, it is a variant of the norm, characteristic of a certain part of the population. With the achievements of modern medicine, women with negative blood become mothers and give birth to healthy children, because the Rh conflict appears in less than half a percent of all cases.
Otherwise, this feature of the blood does not affect the general health of a person in any way - it is absolutely identical to people with a positive Rh, with the exception of a tiny protein.
You can learn more about what a blood type and Rh factor are from the video.
It is said that women with a negative Rh factor are born only same-sex children. Is it true?
No, it is not true, as well as the fact that a negative Rh factor interferes with conception, gestation, childbirth, etc. Rhesus conflict is a very specific complication of pregnancy, and if it is not there, then the negative Rhesus itself does not interfere with anything. See Blood type and Rh incompatibility. Prevention of Rhesus conflict
Is it true that incompatibility by blood group and the Rh factor is dangerous only for boys, i.e. in this case, you can not give birth to boys, and girls will be safe?
No it is not true. It has nothing to do with gender.
Is it true that you can’t have an abortion with a negative Rh - then you will never give birth?
This has little to do with Rh, complications after an abortion are not caused by the Rh factor, but by the complications of the abortion itself. If, after any termination of any pregnancy, a woman with a negative Rh factor injects anti-Rhesus immunoglobulin within 72 hours, then the risk of developing an Rh conflict in subsequent pregnancies does not increase. Abortion should not be done because it is the murder of your child. Not because of rhesus.
Is it true that with a negative Rh in the mother and a positive in the father, the pregnancy proceeds more threateningly, there is a possibility of malformations of the child, he is born sick - and therefore it is better for such a couple not to have children?
No, only a Rh conflict is possible here - a very specific complication that is easy to prevent, anti-Rhesus immunoglobulin will be administered on time at 28 weeks. Other complications with the Rh factor are not related in any way.
Is it true that when mom is Rh positive and dad is Rh negative, there can also be problems with pregnancy and the baby?
No, there can be no problems associated with the Rh factor.
Is it true that when both parents have a negative Rh factor, the child may have complications and malformations up to disability, and such parents should not give birth to children?
No, this is complete nonsense. This is a favorable option, and there cannot even be a Rh conflict and there will be no need to administer immunoglobulin.
And to all such questions about the incompatibility of blood groups and the development of deformities in a child and the inability of people with different groups to give birth - the answers are the same. All these are myths. The only reality is when the mother has the first blood type, and the father has any other - the mother will have to donate group antibodies during pregnancy and monitor their titer, because in this case a blood type conflict is possible. It develops as a Rhesus conflict, after childbirth in a child. Treated in the hospital by pediatricians. It does not lead to other complications of health and pregnancy.
Is it harmful for a pregnant woman to raise and stretch her arms high and far, for example, when you reach out to get a book that stands far away and on a high shelf? Is it true that this causes entanglement of the umbilical cord?
Maybe not true
Is it possible to knit in the later stages, is it true that this causes entanglement of the umbilical cord?
Maybe not true
Sign: the week during which the movements began - plus another 20 weeks = date of birth
Not true
Is it really impossible to hold your breath during pregnancy? For example, in the shower, when I wash my head or when I pass by a speeding transport, I involuntarily hold my breath.
Not true
Can red apples show any of their allergenic properties later in a child if the mother eats them during pregnancy?
No, not related (as with oranges, etc.)
Washing the fetus, menstruation during pregnancy.
Harmful myth. Bloody discharge during pregnancy is always a threat of miscarriage. Requires medical attention and treatment
Is it true that you can not draw during pregnancy, otherwise the child will be born with red spots?
No it is not true
Is it true that you can’t carry small things in your pocket - the baby’s face will be pockmarked?
Is it true that a mother should not sharply grab her face, neck, chest, grab herself in general, as well as hit and fall BECAUSE the baby will have a birthmark in that place?
No it is not true
Is it true that you can’t eat ugly berries, vegetables (it happens that two strawberries or tomatoes grow together, especially this happens in your garden ...), otherwise twins will be born fused?
No it is not true
Is it true that when you don't know the exact father of a child, the real father is the one you feel sexually disgusted with during pregnancy?
No it is not true
Is it true that a pregnant woman should not look at deformities, a fire and a funeral, otherwise the child will be born ugly?
This has nothing to do with the external data of the child, and this sign is connected with the fact that pregnant women just need to avoid stress, and this time can be devoted to communicating with the beautiful, and not vice versa.
They say that in the later stages you need to walk as much as possible, otherwise the placenta will grow.
Is it true that multivitamins during pregnancy cannot be taken all the time, they must be taken in courses, at the end of pregnancy they must be canceled, otherwise you will feed the child heavily?
No, a dangerous myth. They drink multivitamins without interruptions, it is impossible to feed a child with them, the reasons for the development of a large fetus are completely different
Is it true that at the end of pregnancy it is necessary to cancel calcium supplements and foods rich in calcium (for example, cottage cheese), otherwise the bones of the skull will thicken, the fontanel will grow and the placenta will calcify?
Calcium during pregnancy, unlike multivitamins, should be taken only according to indications, with signs of its insufficiency. In this case, of course, there can be no excess. Seals, overgrowth, etc. are not a sign of eating calcium, but of overwearing the child. It is impossible to get excess calcium from food. The placenta for childbirth should be calcified, this is a natural process of its aging, associated not with the removal of excess calcium, but with vascular microinfarctions. It's okay, that's how it should be. As a rule, calcium deficiency already appears in late pregnancy, and blindly following this myth causes pronounced harm.
Is it true that some vitamins (Materna, in particular) are harmful to a child, large children are born from him, there are malformations, etc.?
No. Non-pregnancy multivitamins are high in vitamin A and should not be used during pregnancy. Multivitamins for pregnant women, including Materna, are balanced in composition and contain a minimum of vitamin A and a maximum of beta-carotene. Vitamin A is dangerous only in doses that are many times higher than those in which it is contained in multivitamins, and in these doses it is useful. Dangerous during pregnancy and planning, the drug AEVIT. It contains really teratoric doses of vitamin A, after taking it you need to protect yourself for 6 months
Is it true that in the last months you can’t eat a lot, otherwise you will feed the child or tear the perineum during childbirth?
No it is not true. The size of the child has little to do with the nutrition of the mother, and if she feeds anyone, then only herself. There is nothing good in this in any months of pregnancy and non-pregnancy, so of course there is no need to eat a lot, but not because of these reasons.
And vice versa, is it true that with a developmental delay, a child that does not meet the deadline, the mother needs to eat more in order to “feed” him? Is it true that during pregnancy, the mother should eat "for two"?
No it is not true. The development and growth of the fetus does not depend on the mother's food, rather they depend on the intake of multivitamins and nutritional supplements, and also (primarily) on the characteristics of the blood flow, so the main treatment here is vascular drugs, metabolic therapy and other measures for the prevention and treatment of fetoplacental insufficiency . The weight gain of the child in the latest terms is 35 g per day. So no food “for two” is definitely needed and harmful for the mother!
Is it true that birthmarks appear in a child from sitting at a computer while pregnant?
Not true, although there is nothing good in constantly sitting at the computer. It is necessary to take breaks as often as possible, getting up and leaving the room with computers. And leave work early on maternity leave :)
Is it true that from the moment of conception you begin to gain weight, and if a pregnant woman does not gain or lose weight, or her appetite does not increase, is this bad for the child?
No, it's not. In the first trimester, the child weighs a few grams, and the weight gain of the pregnant woman may not occur; many women lose weight due to toxicosis or the transition to a healthy diet. Weight gain will be noticeable after 20 weeks, so the ideal increase should not be calculated for the entire pregnancy, but for this period (otherwise some are proud of themselves that out of the prescribed 9 they scored “only” 5 by 22 weeks - this turns out to be 5 in 2 weeks, i.e. terrible swelling.In the third trimester of pregnancy, during the maximum weight gain, the child grows by 35 g per day!!!So this increase is water.So no diets other than salt.And no food for two!
They say that discharge during pregnancy is dangerous, because some substances useful for the fetus come out with them?
No, this is an absolute myth, nothing useful comes out of the discharge. But the discharge itself can really be dangerous and require a visit to a doctor.
Is it true that if a pregnant woman's kidneys do not work well, the baby takes on their burden?
No. On the contrary, the kidneys of a woman take on the burden of excreting both from her body and from the child.
Is it true that expensive soy sauces do not contain salt and can be used by pregnant women?
Is it true that after tea you need to drink water, otherwise the tea will linger in the form of swelling?
No, complete nonsense. Any liquid will linger, and the more, the more
Is it true that the bandage affects the child's mobility and position, "fixes" him in the position he is in? Therefore, supposedly, with a breech presentation, the bandage is contraindicated?
No it is not true. The bandage supports the spine, to a lesser extent the muscles of the anterior abdominal wall. But it can not squeeze and limit the mobility of the child.
Is it true that during pregnancy there is a natural decrease in immunity so as not to fight the child's foreign antigens?
No. Immunity is not reduced, otherwise humanity would have died out from epidemic infections in pregnant women. On the contrary, resistance to infections often increases, and in order not to fight the child's antigens, the immune system simply rebuilds, switches to a special mode of operation, and does not weaken at all. It is a myth.
