Effect of alfentanil dosage during oocyte retrieval on fertilization and embryo quality

ObjectiveA possible negative effect of pain-relieving analgesics used during oocyte retrieval on fertilization and embryo development has been discussed. This study examines whether alfentanil dosage adversely affects fertilization and/or embryo quality.Study designIn a retrospective observational study the effect of different doses of alfentanil on two primary endpoints, fertilization rate and good quality embryo (GQE) rate, were compared in 663 women.ResultsIn group A (≤0.5 mg alfentanil) and group B (>0.5 mg alfentanil) mean fertilization rate was 0.6 ± 0.3 versus 0.6 ± 0.2 (P = 0.678, adjusted P = 0.937, 95% CI for the difference −0.041; 0.044) and mean GQE rate was 0.6 ± 0.3 versus 0.5 ± 0.3 (P = 0.207, adjusted P = 0.179, 95% CI for the difference −0.015; 0.078), respectively. A paired comparison of 65 women who underwent repeated IVF cycles found that, compared with ≤0.5 mg alfentanil, doses of >0.5 mg alfentanil had no adverse effects on fertilization rate (mean difference 0.05 ± 0.3, P = 0.231, 95% CI −0.02; 0.12) or GQE rate (mean difference −0.02 ± 0.4, P = 0.970, 95% CI −0.12; 0.09).ConclusionThe amount of alfentanil is not associated with adverse effects on fertilization rate, embryo development, or clinical pregnancy rate, which is reassuring and indicates that women can be offered adequate pain relief.