Rhesus disease only affects the baby. It will not cause any symptoms for the mother.
The symptoms of rhesus disease will depend on how severe it is. Around 50% of babies diagnosed with rhesus disease will have mild symptoms that are easily treatable.
Symptoms in an unborn baby
If your baby develops rhesus disease while still in the womb, they may become anaemic, because their red blood cells are being destroyed faster than usual by the antibodies. If your baby is anaemic, their blood will be thinner and flow more quickly. This will be measured using a type of ultrasound scan known as a Doppler ultrasound.
If the anaemia is severe then it can lead to complications, such as swelling or foetal heart failure. Read more about the complications of rhesus disease.
Symptoms in a newborn baby
The two main problems caused by rhesus disease in a newborn baby are haemolytic anaemia and jaundice. In some cases the baby may also have low muscle tone (hypotonia) and be lacking in energy (lethargic).
If a baby has rhesus disease, they won't always have obvious symptoms when they are born. Symptoms can develop up to three months afterwards.
You can read more about how rhesus disease is diagnosed.
Haemolytic anaemia
Haemolytic anaemia occurs when red blood cells (the cells that transport oxygen in the blood) are destroyed. This happens because the antibodies from the woman’s RhD-negative blood have crossed the placenta and are inside her baby’s blood. The antibodies attack the baby’s RhD-positive blood and destroy the red blood cells. In the newborn baby this may cause:
- increased breathing rate
- poor muscle tone
- poor feeding
- jaundice (see below)
Jaundice
Jaundice occurs as a result of haemolytic anaemia. Jaundice in newborn babies will turn the baby’s skin and the whites of their eyes a yellowy colour. In babies with dark skin, it will be noticed mainly in the whites of their eyes. Their body fluids can also often become yellow in colour.
Jaundice is caused by a build-up of a chemical called bilirubin in the blood.
Bilirubin is a yellow substance that is made naturally in the body when red blood cells are broken down. The bilirubin is carried in the bloodstream to the liver where it is removed from the blood so that it can be passed out of the body in urine. If there is too much bilirubin in the blood, or if the liver cannot get rid of it, the excess of bilirubin will cause jaundice.
In newborn babies, the liver might not process the bilirubin as effectively as it can later in life. This is the reason why up to 50% of newborn babies get mild jaundice. However, in rhesus disease, haemolytic anaemia means that more red blood cells than normal are destroyed. This increases the amount of bilirubin that is released into the blood and the baby's liver is unable to deal with it. The bilirubin levels in the baby’s blood remain high, causing jaundice.
