Most studies suggest that cancer treatment during pregnancy is associated with an increased risk of preterm birth. In a large population-based registry study of more than 2 million children born in Denmark and Sweden, maternal diagnosis of cancer 1 year prior to and up to birth was significantly associated with preterm birth (relative risk ratio [RRR], 1.77; 95% confidence interval [CI], 1.64-1.90).8 Another registry study of a population in Sweden also demonstrated an increased risk of preterm births with small-for-gestational-age (SGA; relative risk, 3.0; 95% CI, 2.1-4.4).1 This study also found an increased risk for stillbirths associated with SGA. Studies report a mean gestational age at birth of approximately 35 weeks or a median of 36 weeks, with most delivered by cesarean section at this time due to oncologic reasons.9,10
The estimated rates of congenital malformations in children exposed to chemotherapy range from 3% to 7.8% among newborns born to mothers with cancer, whereas the birth defect rate for the general population in the United States is approximately 3%.2,11 However, for some agents, this rate may be higher; thus, these agents are typically avoided during pregnancy. For example, exposure to TKIs such as imatinib is associated with higher rates of skeletal, renal, and gastrointestinal malformations.5
A study of outcomes of children (median age of 22 months) of mothers who were diagnosed with cancer during pregnancy demonstrated few long-term problems.10 The majority of mothers received treatment during pregnancy, including 74.4% with chemotherapy, 8.5% with radiotherapy, 10.1% with surgery alone, and 1.6% with other drugs. There was no difference in birth weight, cognitive development, or cardiac function up to 36 months after birth between children born to mothers with cancer compared with those born to mothers without cancer.
Depending on the cancer type, maternal outcomes for most women diagnosed with cancer may be similar to women who are not pregnant during diagnosis and treatment of cancer. For example, women treated for breast cancer or Hodgkin lymphoma during pregnancy demonstrated similar survival outcomes as women who were not pregnant.2,5 However, this may differ for women who must delay appropriate treatment until delivery.
Cancer diagnosis during pregnancy is very rare, occurring in approximately 0.109% of women (based on data from a US study including 775,709 pregnancies from 2001 to 2013).4 Most diagnostic procedures are safe to perform. For many patients, cancer treatment with chemotherapy can begin in the second or third trimester with low risk of harm to the fetus. Treatment with agents such as endocrine therapy, anti-HER2 agents, anti-EGFR therapies, TKIs, and rituximab should be avoided. Radiotherapy is contraindicated. Surgery can be performed with low risk to the fetus.
- Lu D, Ludvigsson JF, Smedby KE, et al. Maternal cancer during pregnancy and risks of stillbirth and infant mortality. J Clin Oncol. 2017;35(14):1522-1529.
- Shachar SS, Gallagher K, McGuire K, et al. Multidisciplinary management of breast cancer during pregnancy. Oncologist. 2017;22(3):324-334.
- Murphy JE, Shampain K, Riley LE, Clark JW, Basnet KM. Case 32-2018: A 36-year-old pregnant woman with newly diagnosed adenocarcinoma. N Engl J Med. 2018;379(16):1562-1570.
- Cottreau CM, Dashevsky I, Andrade SE, et al. Pregnancy-associated cancer: a U.S. population-based study [published online October 10, 2018]. J Womens Health (Larchmt). doi: 10.1089/jwh.2018.6962
- Lishner M, Avivi I, Apperley JF, et al. Hematologic malignancies in pregnancy: management guidelines from an international consensus meeting. J Clin Oncol. 2016;34(5):501-508.
- Song Y, Liu Y, Lin M, Sheng B, Zhu X. Efficacy of neoadjuvant platinum-based chemotherapy during the second and third trimester of pregnancy in women with cervical cancer: an updated systematic review and meta-analysis. Drug Des Devel Ther. 2018;13:79-102.
- Burotto M, Gormaz JG, Samtani S, et al. Viable pregnancy in a patient with metastatic melanoma treated with double checkpoint immunotherapy. Semin Oncol. 2018;45(3):164-169.
- Momen NC, Arendt LH, Ernst A, et al. Pregnancy-associated cancers and birth outcomes in children: a Danish and Swedish population-based register study. BMJ Open. 2018;8(12):e022946.
- Masturzo B, Parpinel G, Macchi C, et al. Impact of cancer in the management of delivery: 10 years of variations. J Matern Fetal Neonatal Med. 2018;20:1-6. doi: 10.1080/14767058.2018.1536117
- Amant F, Vandenbroucke T, Verheecke M, et al. Pediatric outcome after maternal cancer diagnosed during pregnancy. N Engl J Med. 2015;373:1824-1834.
- Danet C, Araujo M, Bos-Thompson MA, et al. Pregnancy outcomes in women exposed to cancer chemotherapy. Pharmacoepidemiol Drug Saf. 2018;27(12):1302-1308.