(726) Fertility treatments in twins pregnancy: Does it increase the risk for future childhood malignancy?

Controversy exists in the literature regarding the association between fertility treatments in singleton pregnancies and long-term risk for childhood neoplasms.  Data regarding fertility treatments in twins and long-term childhood malignancy is scarce. Therefore, we sought to find whether twins conceived following fertility treatments (i.e. in-vitro fertilization and ovulation induction) are at an increased risk for childhood malignancy.

Study Design:

A population-based retrospective cohort study, comparing the risk for future childhood malignancy in twins conceived by fertility treatments and those who were conceived spontaneously, was conducted. Deliveries occurred between the year 1991-2021 in a tertiary medical center. A Kaplan-Meier survival curve was used to compare the cumulative incidence of childhood malignancies and a Cox proportional hazards model was constructed to control for confounders.

Results:

During the study period, 11,986 twins met the inclusion criteria; 2910 (24.3%) were born following fertility treatments. Those twins were at a significantly higher risk for preterm birth before 37 weeks gestation (OR 1.51, 95% CI 1.39-1.65; p < 0.001) and 34 weeks gestation (OR 1.36, 95% CI 1.22-1.55; p < 0.001). No statistically significant differences were noted between the groups comparing the rate of childhood malignancies (P=0.93, Table). Likewise, the cumulative incidence over time was comparable between the groups (log-rank, p=0.87, Figure). In a Cox regression model, controlling for maternal and gestational age, no significant differences in childhood malignancies were noted between the groups (adjusted HR=0.82, 95% CI 0.49-1.39, p=0.47). 

Conclusion:

Twins conceived following fertility treatments are not at an increased risk for childhood malignancies.