[Prevention of Rh D alloimmunization in the first trimester of the pregnancy: French College of Obstetricians and Gynecologists guidelines for clinical practice]

Objective: To provide recommendations for the prevention of Rh D alloimmunization in the first trimester of pregnancy.

Materials and methods: The quality of evidence of the literature was assessed following the GRADE methodology with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on Pubmed, Cochrane, EMBASE, and Google Scholar databases. The quality of evidence was assessed (high, moderate, low, very low) and a recommendation was formulated: (i) strong, (ii) weak, or (iii) no recommendation. The recommendations were reviewed in two rounds with reviewers from the scientific board of the French College of the OB/GYN (Delphi survey) to select the consensus recommendations.

Results: The three recommendations from PICO questions reached agreement using the Delphi method. It is recommended not to administer Rh D immunoglobulin before 12 weeks of gestation to reduce the risk of alloimmunization in case of abortion or miscarriage, in RhD negative patients when the genitor is RhD positive or unknown (Weak recommendation. Very low-quality evidence). It is recommended not to administer Rh D immunoglobulin before 12 weeks of gestation to reduce the risk of alloimmunization in cases of bleeding in an ongoing intrauterine pregnancy (Weak recommendation. Very low-quality evidence). The literature data are insufficient in quality and quantity to determine if the injection of Rh D immunoglobulin reduces the risk of alloimmunization in the case of an ectopic pregnancy (No recommendation. Very low-quality evidence).

Conclusion: Even though the quality of evidence from the studies is very low, it is recommended not to administer Rh D immunoglobulin in case of abortion, miscarriage or bleeding before 12 weeks of amenorrhea. The quality of evidence was too low to issue a recommendation regarding ectopic pregnancy.