Assisted reproduction outcomes after embryo transfers requiring a malleable stylet

OBJECTIVE: This retrospective case-control study was undertaken to assess the impact of a malleable stylet application on embryo transfer (ET) outcome. METHODS: The 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. RESULTS: The 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). CONCLUSIONS: ETs requiring stylet are associated with lower implantation, clinical pregnancy and live birth rates.