Role of saline infusion sonography in uterine evaluation before frozen embryo transfer cycle

ObjectiveTo determine the role of saline infusion sonography (SIS) in uterine evaluation before a frozen embryo transfer (FET) cycle.DesignRetrospective cohort analysis.SettingUniversity hospital.Patient(s)Thirty-six patients who had uterine evaluation by SIS before FET cycle.Intervention(s)The SIS was performed in the follicular phase of the menstrual cycle before the actual FET cycle.Main Outcome Measure(s)The SIS findings, clinical pregnancy rate (PR), ongoing PR, and correlation between positive SIS findings with and without subsequent treatment and pregnancy outcome.Result(s)Positive SIS findings were found in 11/36 patients (30.5%), which included uterine septum (9.0%), endometrial polyp (45.4%), intramural fibroid with normal cavity (9.0%), cystic endometrial changes (9.0%), cervical stenosis (18.1%), and calcification with normal cavity (9.0%). The overall clinical PR in all groups was 51.4%, with an ongoing PR of 45.7%. Patients with positive SIS finding who underwent subsequent hysteroscopic correction (7/11) had a clinical PR of 85.7% as compared to 54.1% in patients with normal uterine cavity (24/35). Patients with positive SIS findings and no operative hysteroscopy (4/11) had a clinical PR of 50% and pregnancy loss rate of 100%.Conclusion(s)Obtaining an SIS before the FET cycle can be helpful in the detection of uterine abnormalities. If time since uterine evaluation has been more than 1–2 years, performing an SIS is recommended as subsequent correction of the anomalies may improve FET outcome.