P-765 Association between oocyte retrieval technique and number of oocytes retrieved
Authors: Ginsburg E , Lanes A , Gordon C 
Published: June 2022

Abstract

Study question
Is there an optimal oocyte retrieval (OR) technique to retrieve a maximum number of oocytes and mature oocytes (MII)?

Summary answer
While certain OR techniques were associated with higher egg to follicle ratios, this did not correlate with more MII oocytes.

What is known already
While there are multiple studies assessing embryo transfer technique and associated outcomes, as well as practice committee guidelines on performing embryo transfers, there are no data on optimal OR techniques and associated outcomes. Studies have compared laparoscopic, transabdominal, transvesicular and transvaginal OR techniques, and transvaginal OR has become the standard of care. However, there are no data on the preferred transvaginal OR technique for retrieving the most oocytes and MII oocytes per follicle cohort.

Study design, size, duration
This was a retrospective study where nine attending physicians completed a survey on OR techniques. Responses were confirmed by fellow trainees not involved in the study who had worked with each physician for at least one year. Number of oocytes/follicle cohort, MIIs/follicle cohort and MIIs/oocytes retrieved (%MII) were assessed for each attending’s technique. Data were stratified by number of follicles on ultrasound on day of trigger (&lt;6, 6-10, &gt;10).

Participants/materials, setting, methods
The parameters evaluated: spatial plane in which the probe was held, direction of retrieval, order of retrieval (by follicle size, or not), retrieval of both large and very small follicles, re-sticking follicles, reversing the probe to retrieve the opposite side, and curetting the follicles or not. The technique with the highest outcome ratio was the referent technique. Adjusted relative risks were calculated controlling for BMI and infertility diagnosis.

Main results and the role of chance
Physicians had different survey responses, resulting in nine techniques, despite eight physicians training at the same institution. Patient demographics were equivalent between techniques. For &lt;6 follicles, three techniques resulted in significantly fewer oocyte/follicle (0.97 +/- 0.48, 0.95 +/- 0.66, and 0.90 +/- 0.41) compared to the top-performing technique (TPT) (1.11 +/- 0.55). There were no significant differences in MII/follicle or %MII. For 6-10 follicles, two techniques resulted in significantly fewer oocyte/follicle (0.95 +/- 0.39 and 0.93 +/- 0.35) compared to the TPT (1.06 +/- 0.42). A different technique had significantly higher %MII (0.77 +/- 0.19) compared to two other techniques (0.74 +/- 0.21 and 0.72 +/- 0.22) within the 6-10 follicle group. For &gt;10 follicles, two techniques resulted in significantly fewer oocyte/follicle (1.01 +/- 0.42 and 1.07 +/- 0.40) compared to the TPT (1.15 +/- 0.41). These two techniques also resulted in fewer MII/follicle (0.75 +/- 0.33 and 0.81 +/- 0.34) compared to the same TPT (0.87 +/- 0.34). There were no significant differences in %MII for this group. There was no consistent TPT across follicle number groups or for all outcome variables. The parameters most associated with TPT were re-sticking and curetting follicles.

Limitations, reasons for caution
While statistically significant, some outcome ratios are similar with wide confidence intervals, limiting the clinical significance of these outcomes. We did not evaluate pregnancy and live birth rates so the results from our study cannot be directly correlated to IVF success.

Wider implications of the findings
There does not appear to be a clear TPT, even for patients with few follicles. Providers who perform OR in a similar fashion to physicians at our institution should feel confident that they obtain equivalent oocyte yields as others.

Trial registration number
Not Applicable