Optimal pregnancy outcome in a minimal-stimulation in vitro fertilization program

We sought to provide a cost-beneficial approach to in vitro fertilization for infertile patients who could not afford the standard treatment with in vitro fertilization and to determine the optimal level of minimal ovarian stimulation to achieve acceptable pregnancy rates.

We performed a retrospective cohort study of 216 patients who underwent "minimal stimulation" in vitro fertilization between January 1994 and December 1998. During the first half of this study, various minimal ovarian stimulation protocols were performed in our private, free-standing center for in vitro fertilization. More recently, more ovarian stimulation, including a 4-day protocol featuring gonadotropin-releasing hormone agonist flare (ultrashort flare), was used. Clinical pregnancy outcome, multiple gestation, complications, and maternal age were compared between the first and second halves of this study.

The average ages of patients in the first half (phase 1) and the second half (phase 2) were similar, 32.4 +/- 0.3 versus 32.6 +/- 0.3 years, respectively. An average of 3.5 oocytes per retrieval was obtained in phase 1 versus 5.9 oocytes in phase 2. Failure to retrieve oocytes occurred in 3% of all cases. The mean number of embryos transferred per patient was 2.0 in phase 1 versus 2.4 in phase 2. In phase 1, 16.1% of patients failed to have viable embryos for transfer, in comparison with 9.7% in phase 2. The overall clinical pregnancy rate per retrieval was 16.9% in phase 1 versus 36. 6% in phase 2. Multiple gestation occurred in 5.0% of clinical pregnancies in phase 1 but increased to 33% in phase 2, with 9 sets of twins and 6 sets of triplets. The implantation rate was 9.3% for phase 1 versus 23.3% for phase 2. The clinical pregnancy rates per retrieval for phase 2 patients were 41.6% in women < or =34 years old and 25.6% for those > or =35 years old. No case of ovarian hyperstimulation syndrome was noted.

Minimal ovarian stimulation in the setting of in vitro fertilization offers a cost-beneficial alternative to standard treatment with in vitro fertilization in infertile patients who are <35 years old and in women <40 years old who have adequate oocyte reserve. More stimulation improves outcome. Minimalstimulation in vitro fertilization provides an alternative for those patients who cannot afford standard in vitro fertilization or who are concerned with exposure to high dosages of fertility medications.