ASCO issues evidence-based guidance for treating blood cancers during pregnancy

A new clinical practice guideline from the American Society of Clinical Oncology (ASCO) provides evidence-based recommendations for managing cancer during pregnancy, including detailed guidance for hematologic malignancies such as leukemia and lymphoma. The guideline emphasizes that pregnant patients with blood cancers can often receive timely, standard-of-care treatment without compromising fetal outcomes and that survival rates can be comparable to those of nonpregnant patients when established protocols are followed.^1,2

The guideline, published in the Journal of Clinical Oncology, was developed by an international, multidisciplinary expert panel following a systematic review of the literature. Mikkael Sekeres, MD, MS, chief of the Division of Hematology at Sylvester Comprehensive Cancer Center at the University of Miami Miller School of Medicine, served as a coauthor.

“I am deeply honored to lend my voice to this collaborative guideline,” said Sekeres. “Being part of a team dedicated to improving care for pregnant patients with cancer is both humbling and inspiring. It’s a privilege to help shape recommendations that can make a real difference for families facing these challenging diagnoses at a vulnerable time in their lives.”

Evidence base and scope of the guideline

According to the guideline authors, a cancer diagnosis occurs in approximately 1 in 1,000 to 2,000 pregnancies, with hematologic malignancies accounting for roughly one-quarter of cases. To inform recommendations, the panel conducted a systematic review that identified 450 eligible studies, the majority of which consisted of observational studies, case series, and case reports. Although randomized trial data are lacking due to the routine exclusion of pregnant patients from oncology trials, the available evidence provides clinically meaningful insight into maternal and fetal outcomes when cancer treatment is administered during pregnancy.

The guideline emphasizes that management should be grounded in a values-based informed consent process, balancing maternal survival—which is essential to fetal survival—with potential fetal risks. Treatment decisions should be revisited throughout pregnancy as gestational age and clinical circumstances evolve.

Diagnosis and imaging considerations

For pregnant patients with suspected hematologic malignancy, the guideline recommends prompt diagnostic evaluation rather than deferral. Ultrasound and magnetic resonance imaging without contrast are recommended as first-line imaging modalities to minimize fetal exposure to ionizing radiation. When tissue confirmation is required, core needle biopsy and bone marrow biopsy are considered safe and effective across all trimesters and should not be delayed.

The guideline advises that diagnostic imaging involving ionizing radiation should follow the “as low as reasonably achievable” principle. Available evidence indicates that fetal radiation doses from most standard diagnostic procedures fall well below thresholds associated with deterministic fetal harm, supporting the use of clinically indicated imaging when necessary.

Systemic therapy and timing of treatment

ASCO recommends that systemic anticancer therapy generally be deferred until the second trimester because of the increased risk of fetal harm during early organogenesis. After the first trimester, however, several standard chemotherapy agents commonly used to treat leukemia and lymphoma—including anthracyclines, vinca alkaloids, and cytarabine—may be administered when clinically indicated.

Certain therapies are contraindicated throughout pregnancy, regardless of gestational age. These include methotrexate, hormonal therapies, human epidermal growth factor receptor 2–targeted agents, vascular endothelial growth factor inhibitors, poly (ADP-ribose) polymerase inhibitors, antibody-drug conjugates, immune checkpoint inhibitors, and cellular therapies.

“I’ve cared for a few pregnant patients with cancer during my career. And each time, treating blood cancers during pregnancy means weighing the needs of two patients. It’s about precision, compassion, and making sure every decision is informed by the patient’s goals, and the best available evidence,” said Sekeres.

Multidisciplinary care and delivery planning

The guideline underscores the importance of a multidisciplinary approach involving hematologists, obstetricians, maternal-fetal medicine specialists, neonatologists, pharmacists, and nursing staff. For patients who continue their pregnancy, delivery is generally recommended at or after 37 weeks’ gestation, with the final chemotherapy dose scheduled 2 to 4 weeks before delivery to reduce the risk of maternal and neonatal myelosuppression.

Supportive care measures—including transfusion support, infection prevention strategies, antimicrobial therapy, and granulocyte colony-stimulating factor when indicated—are considered appropriate to protect maternal health during treatment.

“Every plan should be tailored to the individual. Sometimes treatment begins during pregnancy, sometimes we can delay it until delivery, and other times delivery is timed to allow for therapy to start,” said Sekeres. “The patient’s values and wishes guide every decision.”

Maternal and child outcomes

Long-term follow-up data summarized in the guideline suggest that children exposed to chemotherapy for hematologic malignancies after the first trimester generally do not experience increased rates of congenital anomalies or cognitive impairment. However, risks such as preterm birth, low birth weight, and transient neonatal cytopenias have been reported, underscoring the need for close fetal monitoring and pediatric follow-up.

“Luckily, children of pregnant women with cancer tend to thrive. But we never lose sight of the emotional storms our patients and families endure throughout the process,” Sekeres said. “Psychosocial support is the shelter that helps them weather the storm.”

“Every case is unique,” he added, “but our guiding principle is always the same: do what’s best for both patients. With the right team and the right information, families can move forward with confidence, even when the path is challenging.”

The ASCO guideline reinforces that pregnancy alone should not preclude evidence-based cancer care and provides clinicians with a structured framework to support informed, individualized decision-making for pregnant patients with blood cancers.

References

1. University of Miami Miller School of Medicine. New ASCO guideline maps care for pregnant women with blood cancers. December 12, 2025. Accessed December 18, 2025. https://www.eurekalert.org/news-releases/1109839
2. Loren AW, Lacchetti C, Amant F, et al. Management of Cancer During Pregnancy: ASCO Guideline. Journal of Clinical Oncology. Published online December 11, 2025. doi:https://doi.org/10.1200/jco-25-02115