Your pregnancy: Rhesus factor
MOST if not all antenatal visits start with routine blood tests. These tests allow health care practitioners to obtain information on the expectant mother’s bill of health in addition to facilitating the identification of her blood group and Rhesus factor status.
Rhesus factor, or Rh factor as it is also known, is described by Dr Keisha Buchanan, obstetrician-gynaecologist at ICON Medical, as a protein that is present on the surface of some red blood cells. Most people present with Rh positive blood types, while in a lesser number are those who are Rh negative, which means they are without this protein attachment.
Why is knowing your Rhesus factor status so important, and how could it affect your pregnancy?
“Most women will be Rhesus positive, for example, A positive, O positive, or B positive, and hence will not be at risk of these complications. For those women who are Rhesus negative, for example O negative, a simple blood test will be done to check for the development of these antibodies,” Dr Buchanan said.
She pointed out that having an abnormal blood type such as an absence of the Rhesus factor in the mother can lead to complications arising in the baby’s blood.
“Fortunately, cases of rhesus factor negative women are rare. This can be as rare as one in 1,000 women and these women, when they become pregnant, if their babies present an Rh positive status, then it is possible that the complication Rhesus isoimmunisation will come into play,” Dr Buchanan said.
Rhesus isoimmuniation is an incompatibility disorder where the mother’s blood type is not compatible with that of the foetus. This incompatibility results in antibodies from the mother’s blood destroying the baby’s red blood cells when they come into contact during pregnancy and after birth.
Dr Buchanan said that this complication generally does not affect the woman’s first pregnancy, and is preventable in others that may follow as only one treatment is administered as required.
She said this complication could offset a number of complications both for mother and child including foetal anaemia, jaundice in the baby, premature delivery and in the more severe cases, heart failure and death. As scary as these possibilities may be, Dr Buchanan, while stressing the importance of early blood tests, said that women who have to contend with the possibility of these complications should not be fearful since the condition is treatable and available medications have proven very effective.
“To prevent the development of these antibodies, a medication called Rho (D) immune globulin is given at 28 weeks and 36 weeks during the pregnancy and within three days after delivery to mothers who are Rh negative. It should also be administered within 36 hours after abdominal trauma or vaginal bleeding in pregnancy in order to prevent the antibody development,” Dr Buchanan explained.
Importantly, Dr Buchanan said that is crucial that women who are Rh negative and are miscarrying are also treated with Rho (D) immune globulin because they are also at risk of developing the Rhesus isoimmuniation-causing antibodies.
