Modifiable and non-modifiable risk factors for preterm delivery among adolescent and young adult cancer survivors.

PURPOSE: A cancer diagnosis in adolescence and young adulthood (AYA, ages 15-39) may affect future pregnancy outcomes. Previous studies have reported an increased risk of preterm delivery (< 37 weeks of gestation) after maternal cancer treatment. In this analysis, we evaluated whether non-cancer characteristics modify the association between an AYA cancer history and preterm birth.

METHODS

North Carolina Central Cancer Registry records (2000-2013) were linked to state birth certificate files (2000-2014) to identify births to AYA cancer survivors (n = 1,980). A comparison cohort of births to women without a cancer diagnosis was selected from birth certificate files (n = 11,860). Log-binomial regression was used to estimate risk ratios (RR) and 95% confidence intervals (CI) for preterm delivery. Effect modification by early prenatal care (1st trimester; yes/no), race/ethnicity (white/black/other), previous live births (0/1+), maternal age (< 25/25-29/30-34/35+), smoking during pregnancy (any/none), and education (high school or less/some college/Bachelor's degree or higher) was evaluated using likelihood ratio tests (LRT).

RESULTS

Overall, preterm births were more common among AYA survivors than the comparison group (RR = 1.24, CI 1.07-1.43). The association was stronger among those who did not receive early prenatal care (RR = 1.73, CI 1.26-2.37) than among those who did (RR = 1.15, CI 0.98-1.35; LRT p = 0.03). Maternal age < 25 was also associated with a greater increase in preterm birth (< 25: RR = 1.80, CI 1.27-2.54; LRT p = 0.07). Associations did not vary strongly by other factors evaluated.

CONCLUSIONS

An AYA cancer diagnosis may be associated with an increased risk of preterm birth, particularly among women who are younger and receive late or no prenatal care.