From the moment an egg is fertilized, it is determined what blood type the child will receive. This may be blood group A, B, AB or O. However, there is an additional distinction: the Rhesus factor. This is a protein linked to the red blood cells and occurs in 85% of people. Normally this protein does not cause any problems. However, if a Rhesus negative woman becomes pregnant for the second time with a Rhesus positive baby, this can have far-reaching consequences. What does the Rhesus factor mean, how can a second pregnancy lead to jaundice in the baby and why does it sometimes mean a miscarriage or stillbirth?
Dangers of Rhesus factor baby
- Different blood types
- Positive and negative blood groups
- Separate blood group system pregnancy
- Impact of pregnancy
- Complications
- Rhesus factor and antibody D
Different blood types
When a fetus develops in the womb, it is determined which blood group it has. It is often acquired through inheritance from the parents. Either it is the same blood group or a combination thereof is created. The blood groups are classified into four main types, being A, B, AB and O. This means that blood group A contains antibodies from blood group B and antigen from blood group A. The opposite applies to blood group B. In AB, the antigen from A and B contains antibodies, while blood group O has antibodies A and B. It determines which blood types one can receive and to whom it can be donated. An additional distinction within the blood groups is the Rhesus factor. What influence can it have on the development of the child and why is it harmful during the second pregnancy?
Positive and negative blood types
A specific distinction that occurs within blood groups is the Rhesus factor. This is an antigen, which is also linked as a protein to red blood cells in the Rhesus monkey. In the vast majority of people, this protein is also found in the blood and is also called antigen D. In that case one is Rhesus positive or A+, B+, AB+ or O+. Yet the specific Rhesus protein is absent for 14.75% of the population. In that case it is Rhesus negative or A-, B-, AB- or O-. If a normal healthy person with blood group A- comes into contact with A+, antibody D is produced, so that the resistance is able to cope with it. This normally has no negative consequences for adults, but this is different if the woman is pregnant.
Separate blood group system pregnancy
If the woman is pregnant, the woman’s blood system will be separated from the baby. This provides additional protection against unwanted influences and also makes it possible for the child to have a different blood group. The placenta is responsible for this. It forms the transfer point where nutrition from one blood stream is transferred into the other blood stream. This way the child can be well fed. The problem, however, is that antibody D is not blocked by the placenta.
Impact of pregnancy
If a Rhesus negative woman becomes pregnant, there is a real chance that the child will be born with Rhesus positive blood. This circumstance is not a problem for the first pregnancy as a separate blood system applies. This will change when the child is born. Blood from the child can come into contact with the mother’s blood through the cut umbilical cord and/or placenta. This results in the mother’s immune system producing antibody D to neutralize the influence of Rhesus-positive blood. Even then, this circumstance is not harmful, unless the mother becomes pregnant again with a Rhesus-positive fetus. In that case, the antibody D can be transferred to the baby without a barrier, causing red blood cells to be broken down.
Complications
Breakdown of healthy red blood cells is of course a certainly harmful situation. The capacity to transport oxygen therefore decreases, and blood waste products accumulate in the body. The residual substance of hemoglobin is bilirubin. On the one hand, advanced jaundice occurs, causing the child to look completely yellow. On the other hand, high concentrations of bilirubin pose a danger to brain cells and their neurological development. As a result, several processes are damaged at an early stage, so that the child’s development and growth partly stops or progresses poorly. At high concentrations of this toxin it can sometimes lead to miscarriage, but also death before birth. In other words, the child is then born dead. That circumstance could potentially endanger the mother’s life as well.
Rhesus factor and antibody D
If a Rhesus negative woman has already been pregnant with a Rhesus positive child, there is a real chance that there has been blood contact. A blood test can determine whether antibody D is present in the woman’s blood. If that is the case, it is not wise to become pregnant a second time, because the previous problems have major complications. If you have any questions or would like to have additional children, always consult your GP, gynecologist or other medical specialist.
