Rh Immunoglobulin Uptake With Opt-Out Versus Opt-In Policy in Patients Obtaining Abortion Care at Less Than 12 Weeks...

RhD immune globulin (RhIg) administration in cases of first-trimester bleeding events has historically been recommended to prevent RhD sensitization based on expert opinion and indirect evidence. Emerging evidence has shown that this practice does not improve fetal outcomes, and many medical organizations no longer recommend RhIg administration in the first trimester. We aimed to quantify RhIg uptake by RhD-negative patients at less than 12 weeks gestation receiving abortion care in a clinic system switching from an opt-out to an opt-in policy for RhIg administration. Secondarily, we aimed to analyze characteristics associated with receiving RhIg.

In this retrospective cohort study, we compared RhIg administration in all RhD-negative patients accessing abortion care at less than 12 weeks gestation from August 15, 2021, to August 14, 2022 (pre), and August 15, 2022, to August 15, 2023 (post), in an abortion care clinic system. We compared characteristics to determine differences in those receiving RhIg versus not. RhD-negative patients at greater than 12 weeks gestation were utilized as a comparison. RhIg continues to be recommended to all patients at greater than 12 weeks gestation.

A total of 1,497 RhD-negative patients underwent an abortion at less than 12 weeks gestation, 691 (46.2%) in the pre period and 806 (53.8%) in the post period. The rates of RhIg uptake were 76.1% pre versus 10.4% post (p < .01). In the first 6 months, 88.8% received RhIg and monthly uptake decreased as the official policy change approached. Factors associated with receiving RhIg in the post period were higher gestational age and being Hispanic or Latine. In the comparison group, there was 88.6% uptake in the pre period and 71.4% in the post period.

The rate of RhIg uptake significantly decreased after the policy change, with evidence of an anticipatory effect before the official change. When RhIg was routinely recommended, 23.9% of patients at less than 12 weeks gestation did not receive it. After the policy change to opt-in administration, 10.4% of patients still received RhIg. Further studies on patient risk tolerance surrounding RhIg are warranted.