Anti-D immunoprophylaxis and Rh factor: when should it be done?

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Philippe Gloaguen
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Rh factor, what anti-D immunoprophylaxis is and when it should be done

L'immunoprofilassi anti-D consists in the administration of specific immunoglobulins against the Rh factor (anti-D immunoglobulin), which prevents the production of maternal antibodies against the red blood cells of the fetus. It is simply a 'intramuscular injection on the shoulder. But when should it be done and under what conditions?

In this article

  • Who should do it and when
  • Routine immunoprophylaxis

Who should do it and when?

Immunoprophylaxis must be performed within 72 hours of delivery from all women who have an Rh negative factor and have had a Rh positive baby. In this way, any fetuses from future pregnancies are protected.

Prophylaxis is necessary because, even if there has been no contact between maternal and fetal blood during pregnancy, certainly this contact occurs during delivery.

The first pregnancy becomes a matter of 'certain immunization' due to the contact between the blood of the mother and the baby during childbirth

Also for Rh negative women, immunoprophylaxis is also indicated before childbirth, when there may be contact between maternal and fetal blood, for example in the case of abortion (spontaneous or induced) or threat of abortion, invasive investigations (such as amniocentesis and CVS), extrauterine pregnancy, abdominal trauma, obstetric procedures such as maneuvers for the cephalic version of the fetus.

In all cases of a possible immunizing event, immunoprophylaxis goes without sayingalways performed within 72 hours of the event itself.

Routine immunoprophylaxis

In recent years, also in Del Paese, as is already the case in other countries, the practice (suggested by the guidelines for physiological pregnancy of the Ministry of Health) of carrying out aroutine immunoprophylaxis as early as 28/30 weeks, for all Rh negative women. This is because it has been observed that a substantial number of primiparous produce antibodies against the baby's blood possibly RH positive already in the third trimester of pregnancy (ie before delivery).

For performing anti-D immunoprophylaxis fasting is not required.


  • Guidelines for physiological pregnancy of the Ministry of Health;
  • Documentation center on perinatal and reproductive health of Emilia of the city;
  • Recommendations for the prevention and treatment of haemolytic disease of the newborn of the Del Paesena Society of transfusion medicine and immunohematology;
  • consultancy by gynecologist Giuseppe Noia, associate professor at the Catholic University of the Sacred Heart of the city and head of the Fetal Diagnosis and Therapy Center of the Gemelli Hospital of the city.

  • rh factor
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