A comparison of four systems for uterine septum diagnosis and indication for surgical correction

Existing guidelines do not settle on a specific length to indicate surgical incision of subseptations because of differences in the four published diagnostic methods: AFS-10 mm classification, 1988/2003, ESHRE-ESGE classification, 2013, ASRM criteria, 2016- and 5.9-mm length cut-off, 2017. With this review and data analysis we sought to identify the classification method with the most accurate association with early pregnancy loss, as to identify a subseptation length cut-off to indicate surgical correction.

We performed an exhaustive literature search of PubMed (MEDLINE), Embase, and Cochrane Library databases until April 20, 2020 (limited to articles published in English) of the terms "uterine septum," "arcuate uterus," "subseptation," "Müllerian anomalies," from 1980-2020. After identifying all the available classifications for uterine subseptations, we performed a secondary data analysis of our departmental database on uterine subseptations and compared the identified classification criteria. Measurement of the subseptation's length was obtained on 2-D and 3-D ultrasound in accordance with the different methods. The incidence of uterine subseptations according to each method's specifications was compared among the groups and the association with pregnancy loss was evaluated.

The database comprised 125 women with uterine subseptations and all four diagnostic systems identified septate uteri within it. The 5.9-mm cut-off diagnosed 89 septate, and 36 normal uteri and was the most inclusive while the ASRM cut-off was the most restrictive one, diagnosing 92/125 as arcuate uteri, only 8/125 as septate, and 25 in the gray zone. The AFS-10 mm criteria diagnosed 92/125 as arcuate, and 33 (26.4%) as septate uteri. Subseptations were inconsistently diagnosed by the ESHRE-ESGE classification, as some subseptations longer than 10 mm would be classified as normal uteri. Five/24 women had had one previous early loss and 19/24 had recurrent pregnancy loss. The 5.9-mm system was the most sensitive, while the ASRM was the least sensitive in predicting pregnancy loss (71.2% vs. 9.5% of septate uteri).

The proposed 5.9-mm cut-off was the most sensitive in diagnosing a septate uterus and in predicting an associated early pregnancy loss. Conversely, the AFS-10 mm and the ASRM were the most restrictive, potentially missing treatment for hazardous subseptations. This update highlights the major weaknesses in the current diagnosis of uterine subseptations and indication for surgical treatment. Standardization of clinical practice is essential for reproductive clinicians and efforts should be made to prevent even one further early pregnancy loss to uterine subseptations.