Adverse birth outcomes among offspring born to women diagnosed with cancer: a population-based cohort study

Abstract

With increasing cancer incidence and survival rates, the prevalence of maternal cancer and its effect on adverse birth outcomes are important for prenatal care and oncology management. However, the effects of different types of cancer at different gestational stages have not been widely reported. To describe the epidemiological characteristics of pregnancy-associated cancers (during and one year after pregnancy) and evaluate the association between adverse birth outcomes and maternal cancers. Of 983,162 children, a history of maternal cancer, including pregestational cancer, pregnancy-associated cancer and subsequent cancer, was identified in 16,475 cases using a health information network. The incidence and 95% confidence interval (CI) of pregnancy-associated cancer were calculated with the Poisson distribution. The adjusted risk ratio (RRadj) with 95%CI of the association between adverse birth outcomes and maternal cancer were estimated using the multilevel log binomial model. A total of 38,295 offspring were born to mothers with a cancer history. Of these, 2,583 (6.75%) were exposed to pregnancy-associated cancer, 30,706 (80.18%) had a subsequent cancer diagnosis, and 5006 (13.07%) were exposed to pregestational cancer. The incidence of pregnancy-associated cancer was 2.63/1000 pregnancies (95%CI: 2.53-2.73‰), with cancer of the thyroid (1.15‰), breast (0.25‰), and female reproductive organs (0.23‰) being the most common cancer types. The increased risks of preterm birth and low birth weight were significantly associated with cancer diagnosed during the second and third trimester of pregnancy, while increased risks of birth defects (RRadj=1.48, 95%CI: 1.08-2.04) were associated with cancer diagnosed in the first trimester. An increased risk of preterm birth (RRadj=1.16, 95%CI: 1.02-1.32), low birth weight (RRadj=1.24, 95%CI: 1.07-1.44), and birth defects (RRadj=1.22, 95%CI: 1.10-1.35) was observed in thyroid cancer survivors. Careful monitoring of fetal growth should be implemented for women diagnosed with cancer in the second and third trimester, to ensure timely delivery and balance the benefits of neonatal health and cancer treatment. The higher incidence of thyroid cancer and increased risk of adverse birth outcomes among thyroid cancer survivors suggested that the regular thyroid function monitoring and regulation of thyroid hormone levels are important in maintaining pregnancy and promoting foetal development among thyroid cancer survivors before and during pregnancy.