Work

Inadequate absorption of intramuscular anti-D immunoglobulin in a pregnant woman with a high body mass index

Year: 2025

Type: article

Abstract: Introduction: The D antigen is highly immunogenic, and alloanti-D antibodies in maternal blood may cause haemolytic disease of the foetus and newborn. Prophylactic administration of anti-D immunoglobulin (Ig) to D-negative pregnant women significantly reduces the risk of alloimmunisation. However, absorption after intramuscular (IM) injection may be impaired in obese women. Case description: who received three IM injections of anti-D Ig during pregnancy and after caesarean section. Despite confirmed administration, her indirect antiglobulin tests (IATs) remained negative or only borderline positive. Investigations excluded weak/partial D variants, foetomaternal haemorrhage, chimerism, and other causes. Due to her high BMI, we hypothesised that the injections were administered into subcutaneous fat, resulting in minimal absorption. After intravenous administration of anti-D Ig, the IAT became strongly positive, confirming correct drug delivery. Conclusion: This case highlights the importance of considering maternal BMI in the administration of anti-D Ig. In obese women, inadequate IM administration may compromise prophylaxis. Intravenous administration or the use of alternative injection sites should be considered. LEARNING POINTS: Subcutaneous tissue thickness plays a crucial role in the absorption of intramuscular anti-D immunoglobulin.Women with high body mass index are at risk of inadequate intramuscular administration, which may result in subtherapeutic serum anti-D levels.The intravenous route or careful selection of injection site (e.g., deltoid) should be considered in obese patients.

Source: European Journal of Case Reports in Internal Medicine

DOI: 10.12890/2025_005868

Authors: Ivica Marić, Klara Železnik

Institution: Blood Transfusion Centre of Slovenia

Language: English

Topic: Intramuscular injections and effects

Subfield: Emergency Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $323