Position Statement on Rho(d) Immune Globulin Administration in the First Trimester

This position statement is based on the American College of Obstetricians and Gynecologists (ACOG) Clinical Practice Update published in December 2024 and available online ahead of print in October 2024 (ACOG Clinical Practice Update: Rh D Immune Globulin Administration After Abortion or Pregnancy Loss at Less Than 12 Weeks of Gestation. Obstet Gynecol 2024;144:e140–e143).

The American Society for Reproductive Medicine supports the recommendations in the ACOG Clinical Practice Update regarding Rho(d) immune globulin administration in the first trimester. These recommendations are specific to bleeding, pregnancy loss, and abortion before 12-0/7 weeks of gestation.

Patients at <12-0/7 weeks of gestation who experience vaginal bleeding, pregnancy loss (spontaneous or managed with surgery or medication), or abortion do not require routine Rh testing and RhIg prophylaxis is not recommended. Historically, the risk of Rh D alloimmunization has been estimated to be 1.5%–2% in susceptible women after spontaneous miscarriage and 4%–5% after dilation and curettage. Contemporary evidence suggests that the true risk is substantially lower before 12 weeks. Recent studies indicate that Rh alloimmunization before 12 weeks is highly unlikely as fetal red blood cell concentrations in the maternal circulation were below the estimated sensitization threshold in 99.8% of participants (1). Although a single dose of anti-D immune globulin given to susceptible Rh D–negative women within 72 hours of delivery at term reduced the rate of Rh D alloimmunization by 80%–90%, there are no data to support alloimmunization reduction for bleeding, miscarriage, or abortion before 12-0/7 weeks (2, 3).

Although it is not routinely indicated, Rh testing and RhIg administration can be considered on an individual basis upon patient request in the context of a shared decision-making discussion about the potential benefits and risks. Such circumstances may occur with strong patient preference for treatment, where institutional policies differ, or when circumstances are more complex.

For patients at or beyond 12-0/7 weeks of gestation who are experiencing vaginal bleeding or pregnancy loss, routine Rh testing and RhIg prophylaxis continues to be recommended for Rh-negative, unsensitized patients.

Acknowledgements 

This report was developed under the direction of the Practice Committee of the American Society for Reproductive Medicine (ASRM) as a service to its members and other practicing clinicians. Although this document reflects appropriate management of a problem encountered in the practice of reproductive medicine, it is not intended to be the only approved standard of practice or to dictate an exclusive course of treatment. Other plans of management may be appropriate, taking into account the needs of the individual patient, available resources, and institutional or clinical practice limitations. The Practice Committee and the Board of Directors of ASRM have approved this report. This document was reviewed by ASRM members, and their input was considered in the preparation of the final document. The following members of the ASRM Practice Committee participated in the development of this document: Clarisa Gracia, M.D., M.S.C.E.; Rebecca Flyckt, M.D.; Karl Hansen, M.D., Ph.D.; Tarun Jain, M.D.; Suleena Kalra, M.D., M.S.C.E.; Bruce Pier, M.D.; Denny Sakkas, Ph.D.; Belinda Yauger, M.D.; Torie C. Plowden, M.D., MPH; Ryan Smith, M.D.; Mark Trolice, M.D., MBA; Suneeta Senapati, M.D.; Robert Brannigan, M.D.; Amy Sparks, Ph.D., H.C.L.D.; Jared Robins, M.D.; Chevis N Shannon, Dr.PH., M.B.A., M.P.H.; Jessica Goldstein, R.N. The Practice Committee acknowledges the special contributions of Belinda Yauger, M.D., in the preparation of this document. All Committee members disclosed commercial and financial relationships with manufacturers or distributors of goods or services used to treat patients. Members of the Committee who were found to have conflicts of interest on the basis of the relationships disclosed did not participate in the discussion or development of the document.

References

1. Horvath S, Huang Z-Y, Koelper NC, Martinez C, Tsao PY, Zhao L, et al. Induced abortion and the risk of Rh sensitization. JAMA 2023;330:1167–74.
2. Practice Bulletin No. 181: Prevention of Rh D alloimmunization. Obstet Gynecol 2017;130:e57–70.
3. Society for Maternal-Fetal Medicine, Prabhu M, Louis JM, Kuller JA; SMFM Publications Committee. Society for Maternal-Fetal Medicine Statement: RhD immune globulin after spontaneous or induced abortion at less than 12 weeks of gestation. Am J Obstet Gynecol 2024;230:B2–5.