Birth outcomes among offspring of adult cancer survivors: A population‐based study

Do cancer and cancer treatment influence patients' subsequent pregnancies and outcomes for the offspring? In this study, we compared birth outcomes in 3,915 female and male survivors and 144,653 controls from the general population with similar parity, by merging data from the Cancer Registry and the Medical Birth Registry of Norway. The cancer survivors were diagnosed at age 16–45 in the period 1967–2004. Subgroups of nulliparous survivors (childless before cancer) and primiparous (one pregnancy before and one after cancer) were analyzed, using logistic regression to compare birth outcomes with controls, focusing perinatal death, congenital anomalies, preterm birth (<37 gestational weeks) and low birth weight (LBW, <2,500 g). We adjusted for maternal age, birth period and educational level. Nulliparous female survivors' offspring had increased risk of preterm birth (OR = 1.30 [95% CI 1.05–1.61]) but similar risks of LBW and perinatal death as their controls. Primiparous female survivors differed from their controls, with higher frequency of preterm birth (OR = 1.89 [95% CI 1.40–2.56]) and LBW at term (OR = 2.02 [95% CI 1.15–3.55]). A borderline significant increase of perinatal death was seen among offspring of primiparous female survivors, with OR = 1.92 (95% CI 0.98–3.76). Offspring of male survivors did not differ from their controls. For all cancer types combined, no increased risk of congenital anomalies was seen among either female or male survivors' offspring. Pregnant female cancer survivors should be offered close follow‐up, as there is an increased risk of adverse birth outcomes, in particular among those with higher parities.