Answer for BIR CoW 12 Oct 2025
INCOMPLETE SEPTATE UTERUS
Findings
Uterus measures 3 x 5.6 x 7.8cm and appears normal in size. There is two endometrial cavities noted separated by T2 hypointense septum measuring 1.3 cm extending upto the lower uterine segment with single cervical canal. Angle between the endometrial cavity is 64° (Acute). Internal indentation of about 1.9cm noted. External fundal contour is maintained and appears normal. Bilateral ovaries appears normal IMPRESSION: Two endometrial cavities separated by T2 hypointense septum extending upto the lower uterine segment with single cervical canal and acute angle between the endometrial cavity showing no external contour abnormality. Features of Incomplete septate uterus.
Discussion
SEPTATE UTERUS: A septate uterus is thought to occur from failure of resorption of the uterine septum at approximately the 20th week of gestation. The composition of the uterine septum is variable, ranging from a highly vascular muscular septum to a less vascularized fibrous septum, with implications for pregnancy. Specifically, the more vascularized muscular septum may result in changes to uterine motility and thus cause preterm delivery or miscarriage, while the less vascularized fibrous septum may interfere with implantation. A septate uterus is the most common MDA, accounting for 55% of cases, and is associated with high rates of both first- and second-trimester miscarriage, preterm delivery, and fetal malpresentation. The literature does not support a direct relationship between a septate uterus and infertility; however, there is a lack of consensus on the treatment of patients with infertility and a septate uterus. Current evidence for efficacy of metroplasty for infertility is limited owing to nonuniform definition, diagnosis, and surgical approaches for a uterine septum. There are key differences between the ASRM and ESHRE/ESGE classification systems in the definition of a septate uterus. In both classification systems, a horizontal line of reference known as the interstitial or interostial line is established in the mid-coronal plane of the uterus, connecting the uterine ostia of the fallopian tubes. The external indentation is defined as the depth from a line that connects the apex of the right and left uterine horns with the lowest point of the indentation of the uterine fundus in the midline, whereas the internal indentation is defined as the depth from the interstitial line to the lowest point of the indentation of the uterine cavities. Teaching Point According to the ASRM 2016 guidelines, a normal or arcuate uterus is defined according to the depth of internal indentation of less than 1 cm and an angle of internal indentation of greater than 90°. A septate uterus is defined according to internal indentation of greater than 1.5 cm and less than 90°. A bicornuate uterus is defined according to external indentation of the fundal contour of greater than 1 cm In the ESHGRE/ESGE classification system, external and internal indentation criteria are defined relative to the uterine wall thickness on a midcoronal plane image as the distance between the interostial line and the external uterine contour. When a coronal plane image is not available, the mean of the anterior and posterior wall thickness on a mid sagittal plane image is used as an alternative. According to ESHRE/ESGE criteria, a septate uterus is any uterus with a “normal outline and an internal indentation at the fundal midline exceeding 50% of the uterine wall thickness”. A completely septate uterus is characterized by a septum extending to the internal cervical os, and a partial septate (ie, subseptate) uterus is characterized by an incomplete septum that terminates above the internal cervical os An important change introduced in the EHRE/ESGE classification system was the reclassification of more than one-half of the women who were classified as having an arcuate uterus according to the 1988 American Fertility Society criteria as having a partially septate uterus. An expert panel has suggested that use of the ESHRE/ESGE guidelines likely results in overestimation of the prevalence of septate uteri, while use of the ASRM guidelines likely results in underestimation, leaving a substantial portion of uteri in a “gray zone.” To rectify this, the panel proposed a new set of classification criteria known as the Congenital Uterine Malformation by Experts (CUME) in 2017, which recommended decreasing the threshold depth of internal indentation to less than or equal to 10 mm for diagnosis of a septate uterus. These seemingly minor changes to classification criteria can have a substantial effect on public health. Authors of one study noted that patients who received a diagnosis from the same group of observers showed a prevalence of septate uteri of 5% when the ASRM criteria were used, 12% when the CUME criteria were used, and 31% when the ESHRE/ESGE criteria were used.
REFERENCES:
Müllerian Duct Anomalies: Role in Fertility and Pregnancy https://doi.org/10.1148/rg.2021210022
Findings
Uterus measures 3 x 5.6 x 7.8cm and appears normal in size. There is two endometrial cavities noted separated by T2 hypointense septum measuring 1.3 cm extending upto the lower uterine segment with single cervical canal. Angle between the endometrial cavity is 64° (Acute). Internal indentation of about 1.9cm noted. External fundal contour is maintained and appears normal. Bilateral ovaries appears normal IMPRESSION: Two endometrial cavities separated by T2 hypointense septum extending upto the lower uterine segment with single cervical canal and acute angle between the endometrial cavity showing no external contour abnormality. Features of Incomplete septate uterus.
Discussion
SEPTATE UTERUS: A septate uterus is thought to occur from failure of resorption of the uterine septum at approximately the 20th week of gestation. The composition of the uterine septum is variable, ranging from a highly vascular muscular septum to a less vascularized fibrous septum, with implications for pregnancy. Specifically, the more vascularized muscular septum may result in changes to uterine motility and thus cause preterm delivery or miscarriage, while the less vascularized fibrous septum may interfere with implantation. A septate uterus is the most common MDA, accounting for 55% of cases, and is associated with high rates of both first- and second-trimester miscarriage, preterm delivery, and fetal malpresentation. The literature does not support a direct relationship between a septate uterus and infertility; however, there is a lack of consensus on the treatment of patients with infertility and a septate uterus. Current evidence for efficacy of metroplasty for infertility is limited owing to nonuniform definition, diagnosis, and surgical approaches for a uterine septum. There are key differences between the ASRM and ESHRE/ESGE classification systems in the definition of a septate uterus. In both classification systems, a horizontal line of reference known as the interstitial or interostial line is established in the mid-coronal plane of the uterus, connecting the uterine ostia of the fallopian tubes. The external indentation is defined as the depth from a line that connects the apex of the right and left uterine horns with the lowest point of the indentation of the uterine fundus in the midline, whereas the internal indentation is defined as the depth from the interstitial line to the lowest point of the indentation of the uterine cavities. Teaching Point According to the ASRM 2016 guidelines, a normal or arcuate uterus is defined according to the depth of internal indentation of less than 1 cm and an angle of internal indentation of greater than 90°. A septate uterus is defined according to internal indentation of greater than 1.5 cm and less than 90°. A bicornuate uterus is defined according to external indentation of the fundal contour of greater than 1 cm In the ESHGRE/ESGE classification system, external and internal indentation criteria are defined relative to the uterine wall thickness on a midcoronal plane image as the distance between the interostial line and the external uterine contour. When a coronal plane image is not available, the mean of the anterior and posterior wall thickness on a mid sagittal plane image is used as an alternative. According to ESHRE/ESGE criteria, a septate uterus is any uterus with a “normal outline and an internal indentation at the fundal midline exceeding 50% of the uterine wall thickness”. A completely septate uterus is characterized by a septum extending to the internal cervical os, and a partial septate (ie, subseptate) uterus is characterized by an incomplete septum that terminates above the internal cervical os An important change introduced in the EHRE/ESGE classification system was the reclassification of more than one-half of the women who were classified as having an arcuate uterus according to the 1988 American Fertility Society criteria as having a partially septate uterus. An expert panel has suggested that use of the ESHRE/ESGE guidelines likely results in overestimation of the prevalence of septate uteri, while use of the ASRM guidelines likely results in underestimation, leaving a substantial portion of uteri in a “gray zone.” To rectify this, the panel proposed a new set of classification criteria known as the Congenital Uterine Malformation by Experts (CUME) in 2017, which recommended decreasing the threshold depth of internal indentation to less than or equal to 10 mm for diagnosis of a septate uterus. These seemingly minor changes to classification criteria can have a substantial effect on public health. Authors of one study noted that patients who received a diagnosis from the same group of observers showed a prevalence of septate uteri of 5% when the ASRM criteria were used, 12% when the CUME criteria were used, and 31% when the ESHRE/ESGE criteria were used.
REFERENCES:
Müllerian Duct Anomalies: Role in Fertility and Pregnancy https://doi.org/10.1148/rg.2021210022
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!