Rh Disease

Mismatched blood types between mother and child can trigger a disease known as Rh disease, according to the National Organization for Rare Disorders (NORD). Rh disease only occurs when the mother's blood type is Rh-negative and the baby's blood is Rh-positive, according to NORD. While Rh disease can severely affect the fetus, the March of Dimes (MOD) says it does not affect the mother. Luckily, this disease is on the decline thanks to detection and treatments. Rh disease once affected 16,000 babies a year in this country, but now, according to MOD, about 4,000 infants are born with it each year. The numbers could drop even further if all women who needed the treatment took advantage of it.

Causes

The majority of people in the world have Rh-positive blood. This means their blood has an inherited protein found on the surface of red blood cells. The protein is called the Rh factor. A minority of people lack the Rh factor because they are Rh-negative. MOD breaks down the numbers of Rh-negative people like this:

• 15 percent of the white population
• 5-8 percent of the African American and Hispanic populations
• 1-2 percent of the Asian and Native American populations

While being Rh-negative doesn't have any implications for the adult, an Rh-negative woman's baby is at risk of having the disease if the baby is Rh-positive, according to MOD.

Diagnosis

According to MOD, every woman should have a blood test during her first prenatal visit (Read about "Laboratory Testing" "Prenatal Care"), or even before pregnancy. This will determine whether she is Rh-negative. It can also be crucial in finding out if she has become sensitized.

Sensitization can occur when an Rh-negative mother and an Rh-positive father conceive an Rh-positive baby. A baby has a 50/50 chance of being Rh-positive if the father is Rh-positive and the mother is Rh-negative. If the fetus is Rh-positive and some of the fetus' Rh-positive blood cells get into the mothers blood system, most likely during delivery and birth (Read about "Childbirth"), her body considers them invaders and fights them off by producing antibodies against them. (Read about "The Immune System") There is usually no impact on a woman's first baby if there is an Rh problem since the mother has not yet produced large numbers of antibodies. However, now that she is sensitized, she can pass those antibodies on via the placenta during future pregnancies. Testing of the father's blood may also be warranted to determine if he is positive or negative. If he is negative then there is no danger to the baby who will also be Rh-negative.

There will also probably be tests to determine if the baby is Rh-positive or negative, according to MOD. An amniocentesis (Read about "Pregnancy Testing") can be done to discover if the baby is Rh-positive or negative. It may also be used to determine if the fetus is developing anemia (Read about "Anemia"), which is a serious complication of Rh disease. In addition, according to MOD, an experimental test of the mother's blood may be able to find out if the fetus is Rh-positive or negative. However, it is not yet widely used in the United States. Doppler ultrasound (Read about "Ultrasound Imaging") may also be used to check if the baby is developing anemia.

Complications

Rh disease can be extremely dangerous to an infant whose mother has not undergone treatment. The following is a list of potential complications the baby could suffer, according to MOD.

• death
• brain damage
• jaundice (Read about "Jaundice")
• anemia
• heart failure

Treatment for Mother

An Rh-negative woman who is unsensitized can be treated with shots of a blood product called Rh immune globulin or Rhlg. This, according to MOD, is to help prevent sensitization. A healthcare provider may recommend that if the baby is Rh-positive, the mother receive the injection at 28 weeks of pregnancy and within four days of delivery, miscarriage or ectopic pregnancy. Some specialists also recommend an Rh-negative woman receive Rh immune globulin if a significant trauma occurs during pregnancy, such as a fall or an auto accident. Once a woman is sensitized however, there is no way to turn back the clock, according to MOD.

No injection would be needed if the baby is Rh-negative.

Treatment for Baby

If the baby is close to full term, and tests show he or she is developing anemia, then inducing labor may be the recommendation by the physician. This would prevent the mother's antibodies from destroying too many of the baby's blood cells. Anemia, which used to be fatal, is now treated with blood transfusions and can even be done in the uterus, via the umbilical cord, as early as 18 weeks. After delivery, if the baby has jaundice, he may undergo phototherapy, which is referred to as blue light therapy. Sometimes, Rh disease is so mild, no treatment is needed. In today's world, 90 percent of treated babies can survive Rh disease, according to MOD.

Related Information:

    Pregnancy Resource Center

    Healthy Pregnancy