How to determine the child's blood type by parent? Photo: Getty
It's all about proteins
A method of blood group testing based onanalysis of parental data, can be useful if there are controversial issues about the paternity of the child. This information will help calculate the probability of developing hemolytic disease of the newborn. A life-threatening disease occurs when the mother and child are incompatible in blood group or Rh factor. The division of blood into groups depends on the presence or absence of special proteins in the red blood cells - agglutinogens. There are two types of them, which are usually labeled A and B. If there are no such proteins, then the blood group is called the first. The presence of agglutinogens of type A indicates the second group, B - the third. The presence of both types of proteins implies the fourth group. That is why in medical documents blood groups are indicated as follows: - first - I (0); - second - II (A); - third - III (B); - fourth - IV (AB). Rh factor is a protein antigen contained in red blood cells. Its presence in blood cells is marked as a positive Rh factor, its absence is marked as a negative one. Both parents should know about this antigen to avoid Rh conflict. The risk increases if the father has a positive Rh factor, the mother has a negative Rh factor, and the baby inherits the father's antigen.
How is the blood group passed to the baby?
The dependence of blood group inheritance can betrace. Do both parents have I (0)? Their children are 100% likely to inherit the same. The heir of parents with the second group will receive a similar one in 75 percent of cases. But a quarter of babies have a chance to be born with I (0). With III (B), three quarters of babies are born with the same group in both parents, and a quarter with the first. If mom and dad are carriers of both types of IV (AB) proteins, everything is more complicated. Only half of the children born to such parents inherit their blood composition. The rest have an equal chance of getting II (A) or III (B). It is possible to identify a pattern of genetic transmission with different blood groups in parents. If the mother has the first group, and the father has the second or third (or vice versa), then the baby will inherit one of them. The combination of mom's I (0) and dad's IV (AB) always results in either II (A) or III (B) in the newborn. They cannot have either the fourth or the first group. The same thing happens if the father has I (0) and the mother has IV (AB). When a baby is born to parents with II (A) and IV (AB), he has a 50 percent chance of getting the second blood group. But the child may also have III (B) or IV (AB). And if one of the parents is a carrier of II (A), and the other is III (B), it is unrealistic to calculate the blood group of their offspring. Any option is possible. It is interesting that a person with the fourth blood group, no matter who he marries, will never have an heir with the first. The Rh factor is also determined genetically: - A couple with positive Rh factors can have a baby with or without the antigen. - If the parents have this indicator with a minus sign, the baby will also have a similar one. - With different Rh factors, the baby will inherit one of the parents. When planning a large family, a young couple should take into account the inheritance of both the blood type and the Rh factor. If there are doubts about paternity or the need for a blood transfusion, one cannot take into account only a theoretical calculation. A laboratory study is required. Parents and children take tests, the blood type is calculated as accurately as possible.
