116: The cost-effectiveness of various fetal surveillance strategies in pregnancies complicated by advanced maternal age

Abstract

Advanced maternal age is associated with an increased incidence of intrauterine fetal demise (IUFD). Various strategies of antepartum surveillance have been proposed to decrease the incidence of IUFD, however these are associated with increased medical interventions. We designed a model to examine the cost-effectiveness of various antepartum surveillance strategies. A decision-analytic model with a Markov process was built using TreeAge Pro and incorporated probabilities, costs, and utilities from the literature. We compared the strategies of - starting at 37 weeks gestation - two times weekly non-stress testing (NST), one time weekly NST, and no scheduled antenatal surveillance. We assumed that a non- reactive NST was followed by a biophysical profile (BPP) and then either delivery or return to scheduled surveillance. This model was then applied to a theoretical cohort of 100,000 women, the cost-effectiveness threshold was set to $100,000 per quality-adjusted life year (QALY), and the robustness of the model was assessed with sensitivity analysis. In our model, two times weekly NST resulted in 34,304 positive tests and 487 indicated deliveries, which was 232 more then the one time weekly strategy. The two times weekly strategy resulted in 53 fewer IUFDs compared to the no additional surveillance strategy and 18 fewer IUFDs then the one time weekly strategy (table). In one-way sensitivity analysis, the two times weekly strategy was the cost-effective option up to a NST cost of $357, and up to a BPP cost of $4,418. The two times weekly strategy was the cost-effective strategy with an ICER of $36,610. In pregnancies complicated by advanced maternal age, two times weekly NST is the cost-effective strategy resulting in decreased IUFDs at the expense of increased medical interventions.