Assisted reproduction outcomes after embryo transfers requiring a malleable stylet.

ObjectiveThis retrospective case-control study was undertaken to assess the impact of a malleable stylet application on embryo transfer (ET) outcome.MethodsThe Wallace malleable stylet was used when the soft inner catheter could not negotiate the internal os during ultrasound-guided ET. Patients having an age ≤37 years, with three embryos replaced were included in the analysis. Implantation rate, clinical pregnancy rate and live birth rate were the main outcome measures.ResultsThe Wallace malleable stylet was applied in 164 (29.6%) of the 553 ETs evaluated. Implantation rate, clinical pregnancy rate and live birth rate showed a 5.6% (19.4% vs. 13.8%), a 10.8% (41.9% vs. 31.1%) and a 9.9% (37.3% vs. 27.4%) absolute difference, respectively, in favor of ETs not requiring the stylet. These differences were statistically significant (P < 0.05).ConclusionsETs requiring stylet are associated with lower implantation, clinical pregnancy and live birth rates.