Survivors of childhood and adolescent cancer are less likely than those without a history of these cancers to become pregnant, according to a new study. Childhood and adolescent cancer survivors were also at an elevated risk for severe maternal and cardiac morbidity, and at greater risk for preterm birth. Though, once pregnant, survivors of childhood and adolescent cancer were equally likely to carry a pregnancy over 20 weeks, as those without a history of cancer.
Treatment for cancer can impact fertility for women. Previous studies report conflicting data on the extent of this risk; most rely on self-report, and are not population-based, introducing bias. Many studies to date about female cancer survivors focus on fertility preservation, and few to date have focused on what happens during pregnancy for survivors of childhood and adolescent cancer.
This recently published population-based cohort study used cancer registries to analyse the health records of 4062 female survivors aged 21 years and younger who had been diagnosed with childhood and adolescent cancer in Canada between 1985 and 2012. Childhood cancer survivors were matched 1:5 to women without childhood or adolescent cancer.
Overall in the study, by age 30 years, 22.3% of cancer survivors had a recorded pregnancy, compared with 26.6% of women without childhood cancer. A lower likelihood of pregnancy was associated with a brain tumour, alkylator chemotherapy, cranial radiation, and hematopoietic stem cell transplantation (HSCT).
Once pregnant, the researchers found that cancer survivors were as likely to carry the pregnancy longer than 20 weeks gestation and to have a live birth. However, 9.4% of babies born to cancer survivors were preterm, which was 50% higher than in women not treated for childhood cancer.
The authors found no increase in risk for preeclampsia, caesarean delivery, or gestational diabetes in cancer survivors. However, survivors were twice as likely as controls to develop a serious complication. Overall, 87 out of about 4,062 cancer survivors experienced a serious complication. Serious complications included heart problems, postpartum haemorrhage requiring blood transfusion, or puerperal sepsis during or after birth. Twenty-four cancer survivors required an ICU admission. Survivors treated with an allogenic HSCT were at greatest risk for serious morbidity, with their risk of preterm birth eight times that of the comparison group. Older age at cancer diagnosis was associated with a higher risk of serious complication.
This was a retrospective study, and authors note the limitation that data was not available for women who were attempting to conceive.
In summary, they found cancer survivors were as likely as cancer-free women to carry the pregnancy 20 weeks or longer. However, survivors of childhood or adolescent cancer are less likely to achieve a pregnancy and are at higher risk for severe maternal morbidity and preterm birth. Due to the higher risk of serious complications among survivors of childhood or adolescent cancer, these survivors may benefit from more intensive obstetrical and neonatal monitoring. This is especially important for cancer survivors who have undergone a HSCT.
Study: Obstetrical and Perinatal Outcomes in Female Survivors of Childhood and Adolescent Cancer: A Population-Based Cohort Study. Zgardau A, et al. Journal of the National Cancer Institute, Volume 114, Issue 4, April 2022, Pages 553-564, https://doi.org/10.1093/jnci/djac005