Rh or Rhesus factor is a protein on the surface of red blood cells. It is present in about 85% of the population.
If you have the protein your blood is classified as Rh positive. If the protein is lacking your blood is classified as Rh negative.
If the mother's blood lacks the Rh factor she is Rh negative. And if her partner is Rh positive their baby has a 50% chance of being Rh positive. During her first pregnancy some of the baby's red blood cellsA concave disk containing hemoglobin surrounded by a lipoid membrane. It is the major cellular element of the circulating blood and it serves primarily to transport oxygen. The number of red blood cells is about 4 and 4.5 million per cubic millimeter in women (4.5 and 5 million per cubic millimeter in men).
The average lifespan of a red blood cell is between 110 and 115 days after which it is removed from the bloodstream. New red blood cells are produced at about the rate of 1% daily to keep levels constant. Red blood cells originate in the marrow of long bones. Also called erythrocytes.
Visit our comprehensive glossary for more pregnancy terms and definitions. containing the Rh factor may cross into the maternal blood stream during the last trimester.
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The mother's immune system, recognizing that a foreign substance has entered the bloodstream, creates antibodiesA protein immunoglobulin which is produced naturally by the body and is essential to the immune system by working to combat foreign bodies, germs or bacteria. They are produced by thelymphoid tissue and consist of different classes each of which is designed to fight specific antigens. They include agglutinins, bacteriolysins, opsonins and preciptin.
Visit our comprehensive glossary for more pregnancy terms and definitions. to attack those blood cells. Doctors call this sensitization to Rh positive blood isoimmunization. In most cases the numbers of antibodies made during the first pregnancy are not enough to cause a problem. But the antibodies remain in the mother's bloodstream ready to attack future Rh positive red blood cells.
A subsequent pregnancy with a Rh positive baby will trigger the mother's immune system again, and this time it makes enough of them that some of them will cross the placentaThe placenta is a large disk shaped membrane responsible for providing nourishment to the fetus during pregnancy. It consists of three parts, the fetal part made up from the chorion membrane surrounding the fetus, the maternal part, formed from the decidua basalis layer of the uterine lining, and the intervillous space between the two plates. It is connected to the fetus by the umbilical cord and consists of tissue from both the mother and the embryo.
Its function is complex. It has been described as a simple organ that combines the functions of a kidney-dialysis machine, heart and lung machine and intravenous drip. It consists of enormous numbers of blood vessel branches that permit the exchange of nutrition and oxygen, from the mother's bloodstream to the fetus and the removal of wastes to the mother to be excreted. The placenta's remarkable quality is that it does so without the blood of the mother mixing with that of the baby.
It also is responsible for the production of vital hormones including, estrogen, progesterone, and human chorionic gonadotropin. After birth, the placenta is delivered, and is sometimes referred to as the afterbirth.
Visit our comprehensive glossary for more pregnancy terms and definitions. and attack the Rh positive red blood cells in the baby, a condition called hemolysis. Hemolysis results in the fetus becoming anemic and jaundiced as the liver converts the broken down blood cells into various non-toxic substances.
About fifteen percent (3 in 20) pregnancies have Rh incompatibility. If a Rh immune globulin (RhoGAM) injection is not administered the risk of becoming sensitized is eleven percent (1 in 9) following a delivery, five percent (1 in 20) following amniocetesis or ectopic pregnancy or three percent (1 in 33) after a miscarriage or induced abortion.
During your first prenatal visit you will receive a panel of tests including rh-titer screening. If it is discovered that you are Rh-negative, special precautions will be taken to prevent hemolytic disease of the newborn by administering an injection of Rh-immune globulin or RhoGAMRhoGAM or Rho(D) Immune globulin is a passive immunizing agent which is administered to Rh-negative mothers after abortion, miscarriage, ectopic pregnancy or regular delivery of the baby. Adverse reactions include anaphylaxis.
Visit our comprehensive glossary for more pregnancy terms and definitions. into the muscle in your arm, thigh or buttocks. There are no side effects although the muscle around the injection may become sore.
Rh-immune globulin is a special vaccine designed to treat Rh disease. It contains antibodiesA protein immunoglobulin which is produced naturally by the body and is essential to the immune system by working to combat foreign bodies, germs or bacteria. They are produced by thelymphoid tissue and consist of different classes each of which is designed to fight specific antigens. They include agglutinins, bacteriolysins, opsonins and preciptin.
Visit our comprehensive glossary for more pregnancy terms and definitions. that bind with any red blood cellsA concave disk containing hemoglobin surrounded by a lipoid membrane. It is the major cellular element of the circulating blood and it serves primarily to transport oxygen. The number of red blood cells is about 4 and 4.5 million per cubic millimeter in women (4.5 and 5 million per cubic millimeter in men).
The average lifespan of a red blood cell is between 110 and 115 days after which it is removed from the bloodstream. New red blood cells are produced at about the rate of 1% daily to keep levels constant. Red blood cells originate in the marrow of long bones. Also called erythrocytes.
Visit our comprehensive glossary for more pregnancy terms and definitions. that have crossed the placentaThe placenta is a large disk shaped membrane responsible for providing nourishment to the fetus during pregnancy. It consists of three parts, the fetal part made up from the chorion membrane surrounding the fetus, the maternal part, formed from the decidua basalis layer of the uterine lining, and the intervillous space between the two plates. It is connected to the fetus by the umbilical cord and consists of tissue from both the mother and the embryo.
Its function is complex. It has been described as a simple organ that combines the functions of a kidney-dialysis machine, heart and lung machine and intravenous drip. It consists of enormous numbers of blood vessel branches that permit the exchange of nutrition and oxygen, from the mother's bloodstream to the fetus and the removal of wastes to the mother to be excreted. The placenta's remarkable quality is that it does so without the blood of the mother mixing with that of the baby.
It also is responsible for the production of vital hormones including, estrogen, progesterone, and human chorionic gonadotropin. After birth, the placenta is delivered, and is sometimes referred to as the afterbirth.
Visit our comprehensive glossary for more pregnancy terms and definitions. from your baby. The vaccine will prevent your immune system from becoming stimulated and producing its own antibodies.
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RhoGAMRhoGAM or Rho(D) Immune globulin is a passive immunizing agent which is administered to Rh-negative mothers after abortion, miscarriage, ectopic pregnancy or regular delivery of the baby. Adverse reactions include anaphylaxis.
Visit our comprehensive glossary for more pregnancy terms and definitions. is administered during week twenty eight of your pregnancy. The antibodies in the vaccine only last 3 months, so you may receive additional injections before delivery.
If your baby is born Rh positive you will receive an injection of RhoGAM within 72 hours of delivery, even if this is your first pregnancy. If you are Rh negative and have amniocentesis you will receive the vaccine, and Rh negative women will be administered RhoGAM after a miscarriage, abortion or ectopic pregnancy.
Women who plan to be sterilized postpartum are also administered the vaccine in case the sterilization procedure fails, they require a blood transfusion or they reverse the procedure in future.
If a woman does become Rh sensitized her doctor will discover Rh antibodies when the Rh titer is drawn. In this case RhoGAM will not be effective and not be administered.
If there are large amounts of Rh antibodies the doctor will perform an amniocentesis. The amniotic fluidThe liquid, which is produced by both the fetal membranes and the fetus that surrounds the baby during pregnancy. The liter of fluid at term serves to protect the fetus during pregnancy and also provide active chemical exchange.
The amniotic fluid consists of maternal and fetal plasma in varying concentrations. The pH of the fluid is almost neutral and clear, although lipids and desquamated fetal cells can make it cloudy.
Visit our comprehensive glossary for more pregnancy terms and definitions. will be tested for bilirubinThe broken down red blood cells converted into non-toxic substances in the liver from the hemoglobin. Newborns may have levels of pigment too high for the liver to convert. Also known as bile pigment.
Visit our comprehensive glossary for more pregnancy terms and definitions. and the severity of the effects on the baby will be determined.
For the rest of the pregnancy the course of the hemolytic disease will be monitored with ultrasound. If the effects are mild a normal delivery at term may be possible. If the effects are more severe, then delivery a few weeks before the delivery date may be required.
It some case it is necessary for the fetus to receive a blood transfusion while still in the uterus. Using ultrasound guidance the doctor will insert a needle through the maternal abdomen and uterus into the umbilical cordA flexible structure that connects the fetus to the placenta during pregnancy. It carries blood, oxygen, nourishment and waste to the placenta. It is first formed during the fifth week of pregnancy and contains the yolk sac and body stalk.
Visit our comprehensive glossary for more pregnancy terms and definitions..
Babies born with severe anemia may require an exchange transfusion after delivery. Rh negative blood will be used so that they are not affected by the Rh antibodies produced by the mother and circulating in the baby's bloodstream.
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