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Rh factors happy

30 November 2016

happy-mummyRh factors happy; Mummy and baby happy!

Rh factor is known as the Rhesus factor; a type of protein that is present of the surface of the red blood cell [1]. There are two types of Rh factor differentiated by positive and negative. Rh factor is inherited by parents to their offspring where the probability of offspring to be inherited with Rh positive and negative is 50% respectively if the mother is Rh positive and father is Rh negative or vice versa. On the other hand, both parents with Rh factor negative will give their offspring a 100% of Rh negative inheritance. The probabilities and when the precaution step shall be taken as below [2]:

Mother’s Rh Factor Father’s Rh Factor Baby’s Rh Factor Precautions
+ve +ve +ve None
-ve -ve -ve None
+ve -ve +ve/-ve None
-ve +ve +ve Rh Anti-D IG Injection

Antibody screening shall be done via blood test to identify mothers’ and babies’ Rh factor. This is to avoid Rh factor incompatibilities which will end up giving a negative impact to both mothers and babies like haemolytic diseases leading to jaundice, lethargy and low muscle tone [4]. Mothers’ antibodies will identify babies’ blood cells as foreign substances if both of their Rh factors are different. For instance, mother with Rh negative and baby with Rh positive causes isoimmunisation [2]; mothers’ blood produce antibodies against “foreign substances”. Attacking of antibodies on babies’ blood cells will lead to destroyed red blood cells and augmented amount of bilirubin leading to jaundice after birth.

Anti-D antibody injection can be given to patients with criteria as below:

  1. At around 28th week of pregnancy to prevent Rh sensitization for the rest of the pregnancy.
  2. Within 72 hours after the delivery of the Rh-positive baby.
  3. After a miscarriage, abortion or ectopic pregnancy [1].

As prevention is better than cure, getting a jab containing immunoglobulin with anti-D antibodies to the Rh factor will be a good move [1,3]. Anti-D antibodies will neutralise the Rh positive antigens by the babies. After the neutralisation, mothers’ blood will not synthesise any antibodies to attack the babies’ blood cells as they are neutralised and no foreign substances identified. This injection can be taken each time when the women is pregnant if she meets the criteria of Rh factor incompatibilities. It can also be taken after delivery to minimise the risk to the upcoming babies of hers [4].

By Pharmacy Department, Sri Kota Specialist Medical Centre

References

  1. Karanth, S. H. Jaafar, S. Kanagasabai, N. S. Nair, A. Barua, 2013, Anti-D Administration After Spontaneous Miscarriage For Preventing Rhesus Alloimmunisation, US National Library of Medicine, 28(3).
  2. I. Amarasinghe, G. Kapila, P. Asoka, R. Prasad, R. Chathura, Management of Rhesus Negative Mother, SLCOG National Guidelines, P42-62.
  3. Louis, P. D. Ronald, S. B. Gary, 1984, Clinical Experience With The Prevention of Rh-Isoimmunization: A Historical Comparative Analysis, American Journal of Reproductive Immunology, 5(2), 84-89.
  4. Chilcott, M. L. Jones, K. Forman, J. Wray, C. Beverly, P. Tappenden, 2003, A Review Of The Clinical Effectiveness And Cost-Effectiveness Of Routine Anti-D Prophylaxis For Pregnant Women Who Are Rhesus-Negative, National Centre of Biotechnology Information, 7(4).