retrieved oocytes, number of cryopreserved oocytes, and oocyte maturity at cryopreservation. Characteristics of the variables across different age groups (A < 35, B ¼ 35–37, C ¼ 38–40, D > 40) were analyzed by statistical anal- ysis. Results: Following the completion of an informed IRB consent and all in- dicated screening and counseling procedures, 91 cycles of elective oocyte cryopreservation were initiated in 78 patients. Of these controlled ovarian hyperstimulation cycles initiated, 36 cycles were cancelled due to poor ovar- ian response (fewer than 4 mature follicles) and did not reach oocyte retrieval (39.6%). The mean patient age of the cycles cancelled was 39.0  1.6, with only one patient being cancelled more than one time. Of the 55 cycles (44 patients) that completed ovum retrieval, the ages ranged from 23–42 years, with a mean of 37.2  3.9. The mean number of oocytes retrieved was 13.1  7.8, and ranged from 2–47, while the number of oocytes cryopre- served was 12.9  7.6. Of the 55 cycles that reached retrieval, a quantity of R10 mature oocytes was retrieved and cryopreserved in 18 (32.7%). A de- tailed breakdown of the results is included for each of the patient age groups (A–D) in the table and on the figure below. Age Group A B C D Cycles Cryopreserved 8 16 25 6 Age— mean  SD 30  5.1 36.4  0.7 39  0.8 41.3  0.5 Cryopreserved oocytes per cycle— mean  SD 15.8  8.2 13.3  7.0 12.8  8.4 8.5  1.5 Mature MII oocytes— mean  SD 10.5  8.0 9.1  5.5 9.2  7.7 5.7  1.5 Immature MI oocytes— mean  SD 3.1  2.2 3.7  2.9 2.9  3.6 2.3  1.5 Immature GV oocytes— mean  SD 2.1  2.0 0.5  0.7 0.6  0.8 0.5  0.6 Cycles with R10 MII oocytes 50% 44% 28% 0% Oocytes cryopreserved by age group (p<.001) 0 2 4 6 8 10 12 MII MI GV Maturity of oocytes Mean number of oocytes A B C D Conclusions: Our preliminary experience with offering elective oocyte cryopreservation for fertility preservation resulted in 91 cycles being initi- ated. Our high cycle cancellation rate of 39.6% is probably due to the in- creased age of our patient population presenting for this elective procedure and is demonstrated by the mean age of those patients who were cancelled (39.0  1.6). Of the 44 patients who completed the 55 cycles analyzed in our study, the mean number of oocytes retrieved across all patients was 13.1, yet only 32.7% of cycles yielded the optimal R10 mature oocytes for cryopreservation. The results, when broken down by age group, demon- strate that there is a decline in total oocytes available for cryopreservation as age increases (Table). Additionally, the number of mature oocytes available for cryopreservation significantly declines when analyzing across the patient age groups (p< .001) (Figure). The number of cycles having R10 mature oo- cytes for cryopreservation, initially at 50% of cycles in the youngest age group, declines dramatically after the age of 37. Our analysis of the elective oocyte cryopreservation cycles suggests that the age of the patient signifi- cantly affects the cancellation rate, as well as both the quantity and maturity of the oocytes available for cryopreservation. These findings suggest that patients are presenting after the age at which this elective procedure could most optimally serve. Education and counseling of the younger female pop- ulation, for which this new technique is most advantageous, will have to be further developed for the greatest benefit to fertility preservation P-26 Volumetric Measurement of Pituitary Adenomas Using the Slice-O- Matic Software Program, a Novel Approach to Evaluation of Pituitary Tumors. M.J. Kalan, H. Hosein, R.H. Fogel, K. Stearns, K. Kulig, R.J. Paulson, R.Z. Sokol. Department of OB/GYN, University of Southern California; Department of Radiology, University of Southern California; Division of Biokinesology and Physical Therapy at The School of Dentistry, Department of Orthopaedic Surgery, University of Southern California, Los Angeles, CA. Backround: During treatment of prolactinomas, the decrease seen in pro- lactin level is often much greater than that seen in tumor size. We speculate that this discrepancy may be attributable to imprecise tumor measurement us- ing standard measurement techniques. Because prolactinomas are often ir- regularly shaped, measurements based on ovoid formulas may not be accurate. Thus, we applied the Slice-O-Matic (SOM) software program (To- moVision, Canada), which calculates volumes on 3D images constructed from 2D studies, to evaluate prolactinoma volumes in patients treated with bromocriptine. Objective: To determine if volumetric analysis using SOM correlates more closely with decreases in prolactin levels compared to analysis using stan- dard measurement techniques. Materials and Methods: Subjects from the LACþUSC reproductive endo- crinology clinic who were diagnosed with prolactinoma on MRI, treated with bromocriptine, and then had a follow-up MRI were identified. Pre- and post- treatment prolactin levels were determined by chart review. MRIs were re- viewed by a radiologist who quantified tumor size by height, width, and depth, as well as by SOM. Volume was calculated using the standard ovoid formula and compared to the volume generated by SOM. Results: Five subjects met inclusion criteria. Tumors measured by SOM were significantly larger than those measured by standard technique (684 mm 3 vs 408 mm 3 p< .05). A statistically significant correlation between change in tumor volume as measured by SOM and percent decrease in serum prolactin was demonstrated (r ¼ 0.92, p< .05). However, no statistically sig- nificant correlation was noted between change in tumor volume as measured by standard technique and decrease in serum prolactin (r ¼ 0.82, p¼ .08). Conclusions: Prolactinoma volume determined by SOM is significantly greater than volume determined by standard techniques. The decrease in pro- lactin levels during bromocriptine therapy correlates well with the decrease in prolactinoma volume as determined by SOM. SOM may provide a more accurate estimation of prolactinoma size than standard measurement techniques. P-27 Frozen Anonymous Oocyte Donor Cycles: Predictors of Success. S.B. Hudson, D.L. Walker, L.L. Tatpati, D.E. Morbeck. Division of Reproductive Endocrinology & Infertility, Department of Obstetrics & Gynecology, Mayo Clinic, Rochester, MN. Background: While anonymous oocyte donation (AOD) yields high preg- nancy rates, some recipients fail to conceive with their initial AOD cycle but are successful with a different donor. Objective: We chose to analyze donors that failed to yield a pregnancy in a recipient who later proved fertile with a second donor. We compared the donor’s failed AOD cycles to successful donation cycles to determine if cycle characteristics were predictive of outcome. Materials & Methods: IRB-approved retrospective analysis of AOD cycles of donors that failed to yield a pregnancy in a recipient compared to cycles of the same donors in other recipients yielding pregnancy. Results: Cycle outcome measures and embryo characteristics were ana- lyzed for the two groups. Analysis of retrieval and transfer outcomes are found in Table 1 and 2, respectively. FERTILITY & STERILITY Ò S21