Case Study Highlights Risk of Pancytopenia in Methotrexate Treatment for Cesarean Scar Pregnancy

Cesarean scar pregnancy is a rare and potentially dangerous type of ectopic pregnancy where implantation occurs at the site of a previous cesarean section scar. While methotrexate (MTX) is commonly used to manage CSP due to its efficacy in stopping abnormal pregnancies, its administration is linked to a range of side effects, including hematological toxicities.

Sofoklis Stavros, National, and Kapodistrian University of Athens, Athens, Greece, and colleagues presented a case report highlighting a cesarean scar pregnancy treated with an intragestational injection of methotrexate. The patient subsequently developed pancytopenia, a rare but serious complication of MTX therapy, emphasizing the need for caution even with localized, low-dose administration.

The case concerns a 23-year-old woman at six weeks and six days of pregnancy who was referred with a suspected cesarean scar pregnancy. Following confirmation of the diagnosis, she underwent treatment involving a transvaginal ultrasound-guided intragestational injection of 80 mg methotrexate, adjusted to 50 mg/m² of body surface area, administered under sedation.

Four days after the procedure, the patient developed oral ulcers, fever, and a pruritic phlyctenular maculopapular rash. Her condition progressed to febrile neutropenia, necessitating admission to the Intensive Care Unit (ICU). By day six, her symptoms worsened, with an exacerbation of the rash characterized by blisters and purplish spots, accompanied by odynophagia (painful swallowing) and sialorrhea (excessive salivation). The patient ultimately developed pancytopenia due to bone marrow suppression.

Despite the severe complications, the patient gradually improved with appropriate medical management. By the 15th day post-MTX administration, she had recovered fully and was discharged in stable condition. Her β-hCG levels had significantly decreased, indicating resolution of the CSP, and she was afebrile and hemodynamically stable upon discharge.

"While methotrexate is a highly effective treatment for cesarean scar pregnancies, clinicians must remain vigilant about the potential risks associated with its use, even when administered locally. This case represents, to our knowledge, the first reported instance of pancytopenia resulting from bone marrow suppression following a single intragestational methotrexate injection for cesarean scar pregnancy," the researchers wrote.

"Further research is crucial to optimize the management of such complex cases, ensuring the best outcomes through minimally invasive and fertility-sparing approaches."

"The report highlights the importance of close monitoring and early intervention when using MTX for CSP and other similar conditions. As this case marks the first documented instance of pancytopenia following a single low-dose intragestational MTX injection, it serves as a critical reminder of the balance required between therapeutic efficacy and patient safety," they concluded.

Reference:

Stavros, S., Potiris, A., Gerede, A., Zikopoulos, A., Giourga, M., Karasmani, C., Karpouzos, A., Karampitsakos, T., Topis, S., Anagnostaki, I., Louis, K., Tsakiridis, I., Dagklis, T., Drakakis, P., & Domali, E. (2024). Methotrexate-Induced Toxicity After Ultrasound-Guided Intragestational Injection in a Patient with Caesarean Scar Pregnancy—A Case Report. Medicina, 60(11), 1900. https://doi.org/10.3390/medicina60111900