Different influence of incongruent follicular development on in vitro fertilization-embryo transfer and gamete intrafallopian transfer pregnancy rates.

Objective: To compare the influence of incongruent (asymmetric) follicular development on treatment outcome in IVF-ET and GIFT cycles.

Design: A retrospective comparative study.

Setting: Tertiary referral center for infertility.

Patient(s): Five hundred forty-three consecutive assisted reproduction cycles (428 IVF-ET and 115 GIFT) in 422 infertile patients.

Intervention(s): Controlled ovarian hyperstimulation (COH) and IVF-ET or GIFT.

Main Outcome Measure(s): The incongruity ratio as a parameter of the asymmetry in follicular development and pregnancy rate (PR).

Result(s): For GIFT cycles, the PRs were 37.8% and 15.7% in cycles with congruent and incongruent follicular development, respectively. However, for IVF-ET cycles, the PR was not affected by incongruent follicular development: 28.2% and 29.0%, respectively. An inverse relationship was observed between the degree of incongruity and the estimated probability of pregnancy in GIFT cycles but not in IVF-ET cycles. Neither the side of the dominant ovary nor the degree of incongruity were consistent in consecutive cycles.

Conclusion(s): Incongruent follicular development during COH has a significantly negative influence on the outcome of GIFT cycles but not on the outcome of IVF-ET cycles. The reason for this difference is not clear. We recommend considering IVF-ET instead of GIFT if incongruent follicular development occurs.