The Society for Maternal-Fetal Medicine (SMFM) and the American Society of Clinical Oncology (ASCO) recently released a consensus statement and clinical practice guideline, respectively, on managing cancer during pregnancy. The SMFM consensus statement, Cancer in Pregnancy, was released in early March of 2026, while the ASCO clinical practice guideline, Management of Cancer During Pregnancy, was released in December of 2025.
Today, we’re taking a look at the consensus statement from SMFM alongside overlapping portions of the clinical practice guideline from ASCO. With the ASCO guideline featuring over 60 individual recommendations, for brevity, we’re comparing the recommendations that align with the 14 SMFM recommendations. The full-text versions of the consensus statement and clinical practice guideline are available at the links below.
Guidelines for Comparison
| Item | Cancer in Pregnancy | Management of Cancer During Pregnancy |
|---|---|---|
| Authoring Organization | Society for Maternal-Fetal Medicine | American Society of Clinical Oncology |
| Published | March 2026 | December 2025 |
| Links | Summary / Full Text | Summary / Full Text |
Key Comparisons Between the SMFM and ASCO Guidance on Cancer During Pregnancy
The most obvious differences between the two publications are type and scope. The SMFM consensus statement features 14 recommendations, while the ASCO clinical practice guideline features 67 recommendations. The SMFM statement provides two recommendations on diagnosis, while the ASCO clinical practice guideline provides seventeen recommendations on diagnosis alone.
The SMFM and ASCO guidance on cancer during pregnancy both feature recommendations on diagnosis, surgery, chemotherapy, thromboprophylaxis, delivery, and more.
Regarding surgery, SMFM recommends that surgery for cancer not be withheld at any point during the gestational period. ASCO recommends surgery when clinically indicated, with a few caveats including a focus on the prevention of maternal hypoxia, avoiding supine positioning after 20 weeks' gestation, using regional anesthesia when feasible, and coordinating with a multidisciplinary team.
Regarding thromboprophylaxis, SMFM recommends thromboprophylaxis for active hematological or gynecological cancers during pregnancy, and to consider it for patients with nonhematological or nongynecological cancers during pregnancy, based on individual risk factors. ASCO’s recommendation regarding thromboprophylaxis focuses on postpartum patients and recommends VTE prophylaxis with low molecular weight heparin for at least six weeks to reduce the risk of clotting.
The following side-by-side comparison table showcases the similarities and differences between the SMFM and ASCO recommendations on cancer during pregnancy.
| Topic | SMFM Consensus Statement Recommendations | ASCO Clinical Practice Guideline Recommendations |
|---|---|---|
| Diagnosis | We suggest that ultrasonography and non-contrast MRI be used as first-line imaging techniques in the evaluation of a pregnant person with suspected cancer. Although non-contrast MRI and ultrasonography are first-line diagnostic imaging modalities in pregnancy, we recommend that CT with or without contrast, gadolinium contrast for MRI, and 18-FDG-PET/CT not be withheld from a pregnant person if clinically indicated. | For pregnant patients with a palpable mass or signs or symptoms suspicious for, but without confirmation of malignancy, clinicians should immediately refer for diagnostic imaging with clear communication to the imaging facility that the patient is pregnant to ensure appropriate imaging protocols. Ionizing radiation-based procedures should only be used when clinically necessary, following the “as low as reasonably achievable” (ALARA) principle to minimize fetal exposure. Clinicians should order ultrasound as the first-line imaging tool whenever possible due to its safety and absence of radiation exposure. Clinicians may use MRI without contrast when further staging or clarification is necessary. Clinicians should avoid routine use of gonadal and fetal shielding devices during X-ray–based diagnostic imaging, as they provide minimal benefit, can reduce radiological image quality, and may increase scatter, potentially exposing embryo or fetus to higher radiation levels. Clinicians may use X-rays of the head and neck, chest, or extremities when clinically indicated, as fetal radiation exposure is minimal. Clinicians may use mammography as an adjunct to ultrasound in pregnant patients with suspicious breast findings. When mammography is performed, bilateral imaging is recommended as part of the diagnostic workup to avoid missing bilateral disease. For pregnant patients requiring advanced imaging for malignancy, clinicians should avoid abdominal CT, abdominal X-ray, PET-CT, bone scintigraphy, and other radionuclide studies unless essential for diagnosis, staging, and/or treatment planning. If required or indicated, timing should be individualized considering the urgency of diagnosis, the potential impact of delayed cancer detection or inaccurate staging, and the risks to both the patient and her embryo or fetus. Dose-reduction techniques should be applied to reduce fetal exposure. Clinicians should avoid GBCAs unless absolutely necessary due to potential fetal exposure and risks of neonatal rheumatic and inflammatory conditions or stillbirth. If there are no safer alternatives and GBCA use is unavoidable, clinicians should use the lowest possible dose. For pregnant patients requiring iodinated contrast for imaging, clinicians should be aware of the risk of neonatal hypothyroidism. When no safer alternatives are available and iodinated contrast is unavoidable, its use should be carefully evaluated through transdisciplinary collaboration. Neonates exposed to iodinated contrast in utero should have thyroid function evaluated through standard newborn screening for congenital hypothyroidism at birth. For pregnant patients requiring imaging for thyroid cancer, radioactive iodine is contraindicated. Clinicians should use ultrasound as the first-line imaging tool. For pregnant patients with suspected malignancy, clinicians should not rely solely on serum tumor markers for cancer diagnosis, as physiological changes during pregnancy can alter some marker levels and reduce sensitivity and specificity. When tumor markers are tested, results should be interpreted with caution and in conjunction with other assessments. When biopsy is planned, clinicians should prioritize core needle biopsy or excisional biopsy over fine-needle aspiration, to preserve tissue architecture and reduce diagnostic delays. This is an important consideration in all patients, but especially in pregnancy, where timely diagnosis can be critical for optimizing maternal and fetal outcomes. For pregnant patients who would benefit from sentinel lymph node evaluation, clinicians should perform SLNB, with technetium-99m (Tc-99) preferred over blue dye to reduce the risk of maternal anaphylaxis. When clinically appropriate, a 1-day, low-dose Tc-99 protocol can be used to minimize fetal radiation exposure. For pregnant patients with suspected cervical cancer, clinicians may perform colposcopy during any trimester when necessary to establish a diagnosis. Endocervical curettage should be avoided to reduce preterm labor risks. For pregnant patients requiring GI endoscopy for suspected cancer, clinicians may perform endoscopic procedures, with transdisciplinary discussions about risk and timing. For pregnant patients with abnormal noninvasive prenatal screening results that may be suggestive of possible cancer, clinicians should evaluate with appropriate workup. |
| Thromboprophylaxis | We recommend initiating thromboprophylaxis for all patients with active hematological or gynecological cancers during pregnancy and considering thromboprophylaxis for all patients with nonhematological or nongynecological cancers during pregnancy, based on individual risk factors. | For postpartum patients with cancer, clinicians may initiate VTE prophylaxis with low molecular weight heparin for at least 6 weeks to reduce clotting risks. Decisions regarding VTE prophylaxis should be individualized based on factors such as a history of VTE, cancer type and stage, obstetric mode of delivery, immobility, ongoing cancer therapy, and benefits versus risks. |
| Surgery | We recommend that surgery for the treatment of cancer not be delayed or withheld from a pregnant patient at any gestational age in pregnancy. | Surgeons should perform surgery on pregnant patients with cancer when clinically indicated, implementing strategies to optimize maternal and fetal outcomes. To minimize risks, the surgical team should prevent maternal hypoxia, avoid supine positioning after 20 weeks' gestation, use regional anesthesia when feasible, and coordinate with a multidisciplinary team to guide perioperative management. |
| Chemotherapy | We recommend that chemotherapy generally be administered after 12 weeks of gestation, provided that the patient desires to continue the pregnancy and that delaying treatment until after 12 weeks of gestation is not expected to significantly change the pregnant patient's prognosis compared with initiating treatment immediately after diagnosis. | For pregnant patients with cancer requiring systemic therapy, if the patient intends to continue the pregnancy, clinicians should try to avoid administering conventional cytotoxic chemotherapy during the first trimester due to high teratogenic or abortifacient risks. Clinicians may administer alkylating agents such as cyclophosphamide, ifosfamide, and dacarbazine in the second and third trimesters. Clinicians should not administer methotrexate in any trimester due to its teratogenic and abortifacient effects. Alternative treatments should be offered, or therapy should be delayed until after delivery. Before initiating fluoropyrimidine chemotherapy such as 5-FU and capecitabine in pregnant patients with cancer, the Panel recommends genetic testing to identify those with DPD deficiency due to genetic variations in the DPYD gene, to mitigate the risk of serious adverse reactions. Clinicians may administer 5-FU and capecitabine in the second and third trimesters, with DPYD genotype-guided treatment modification when indicated. Gemcitabine may also be administered in the second and third trimesters. Clinicians may administer platinum agents such as carboplatin, cisplatin, and oxaliplatin in the second and third trimesters. Carboplatin is preferred over cisplatin due to lower fetal ototoxicity risks when compared with cisplatin. Clinicians may administer anthracyclines such as doxorubicin, epirubicin, and daunorubicin in the second and third trimesters. Clinicians should avoid the use of idarubicin in all trimesters, due to risk of congenital malformations, fetal cardiotoxicity, and pregnancy loss. If no other anthracycline is felt to be an appropriate substitute, the patient should be counseled about limited safety data for using idarubicin in pregnancy. Clinicians may administer topoisomerase inhibitors such as irinotecan and etoposide in the second and third trimesters. Clinicians may administer vinca alkaloids such as vincristine, vinblastine, and vinorelbine in the second and third trimesters. Clinicians may administer taxanes such as paclitaxel and docetaxel in the second and third trimesters. |
| Medications for Chemotherapy Side Effects | We recommend intravenous methylprednisolone, 62.5 mg (corresponding to 10 mg of dexamethasone), or oral prednisolone, 30 mg (corresponding to 6 mg of dexamethasone), as first-line therapy for chemotherapy-induced nausea when corticosteroids are indicated. | Clinicians may offer antiemetics such as ondansetron or metoclopramide for treatment-induced nausea and vomiting. Use of other antiemetic agents such as prochlorperazine, olanzapine, and NK1 receptor antagonists should be guided by multidisciplinary consultation, as efficacy for treatment-induced nausea and vomiting and/or fetal safety data remain limited. Glucocorticoids, preferably prednisolone or methylprednisolone, may be used when needed. Clinicians may offer G-CSF to reduce the risk of febrile neutropenia when clinically indicated, such as with myelosuppressive chemotherapy. Decisions should be based on individual risk factors, gestational age, and benefits versus risks. |
| Fetal Ultrasound Surveillance | We recommend serial fetal growth surveillance every 3–4 weeks in pregnancies with an active cancer diagnosis, regardless of treatment. We recommend initiation of antenatal fetal surveillance starting at 32 weeks of gestation in pregnancies with an active cancer diagnosis, regardless of treatment, unless indicated earlier for maternal or fetal reasons. | For pregnant patients undergoing cancer treatment, clinicians should schedule fetal monitoring that includes at least every three-to-four-week ultrasounds starting at 22-24 weeks to assess fetal growth, amniotic fluid levels, and placental function. |
| Delivery | To improve long-term neurodevelopmental outcomes of children exposed to chemotherapy in utero, we suggest avoiding clinician-initiated preterm delivery when possible. We recommend that planned delivery prior to 37 weeks of gestation in pregnant patients with cancer generally be avoided unless indicated for medical or obstetrical reasons. We recommend that chemotherapy treatment generally be stopped by 34 weeks of gestation to allow 3–4 weeks for recovery of myelosuppression before spontaneous labor or planned delivery, except for weekly paclitaxel, which can be administered up to 35 or 36 weeks, as only 1–2 weeks are necessary for recovery before delivery. We recommend that the mode of delivery be determined by routine obstetrical indications for most patients with cancer in pregnancy. We recommend a placental pathology examination in all cases of cancer during pregnancy, regardless of cancer type or treatment. | Obstetricians and oncologists should collaborate closely to plan delivery at or after 37 weeks of gestation to minimize prematurity risks, unless maternal or fetal health conditions require earlier intervention. Clinicians should plan to administer the last chemotherapy dose 2-4 weeks, or one complete cycle, prior to delivery, to minimize the risks of maternal and neonatal myelosuppression at delivery. Clinicians should prioritize vaginal delivery, as per standard practice and considerations, unless standard obstetric conditions or malignancies such as cervical or vulvar cancer necessitate cesarean section to optimize maternal and neonatal outcomes. Clinicians may administer a single course of antenatal corticosteroids to promote fetal lung maturation for pregnant patients with delivery planned or imminent prior to 37 weeks. A histological evaluation of the placenta is recommended immediately after delivery in pregnant patients with a cancer diagnosis to guide oncological evaluation in the neonate. If placental metastases are detected, consult with a neonatologist for follow-up of neonate. |
| Additional Considerations | We recommend that cancer be considered as part of the differential diagnosis for pregnant patients with multiple chromosomal aneuploidies or single autosomal monosomy detected by cfDNA screening that is discordant with fetal findings. | N/A |
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