A 35-year-old woman visits your clinic after several unsuccessful attempts at ovulation induction (OI) elsewhere (including 2 cycles of Clomid). You start her on Follistim, 50 IU/d, with microtitration. She produces one follicle; no pregnancy results. In her second cycle, you switch her to Bravelle, 75 IU/d; she produces 2 mature follicles and has a positive pregnancy, which results in a missed abortion due to a trisomy. In the third cycle, you give her Bravelle at 150 IU/d for the first 3 days, then reduce the dose to 75 IU/d. She produces 4 mature follicles; no pregnancy results. What is the next step for this patient?