Reply: T-shaped uterus after oral contraception-considering myometrial contractions, endometrial volume and 3D saline contrast sonohysterography in diagnosis.

Abstract

We thank Drs Leone and Cammarata for their interest in our systematic review and for sharing their important observations on the possibility of overdiagnosis of T-shaped uterus in women taking oral contraceptives (OC). The authors observed that, in a patient with a normal uterus, a T-shaped appearance was noted after commencement of oral contraceptives (OC), while, in a patient with an apparent T-shaped uterus during OC use, normal uterus was noted after discontinuation of OC. The authors highlighted the transient nature of this uterine morphology and the risk of overdiagnosis and unnecessary intervention. Indeed, the diagnosis/overdiagnosis of specific anatomic entities under the term ‘congenital uterine anomaly’, similarly to the false assumption based on biased before–after studies that correcting the uterine cavity shape to a perfect triangle is beneficial, expands the market for unnecessary hysteroscopic interventions1, 2. The Congenital Uterine Malformation by Experts (CUME) group suggested three sonographic uterine measurements which can be used to distinguish between three types of uterine morphology in the presence of lateral indentation but no significant internal fundal indentation: normal uterus; borderline T-shaped uterus; and T-shaped uterus3, 4. In contrast to the previous arbitrary classifications of T-shaped uterus, such as that of the American Fertility Society (AFS) which provided no strict definition and limited the diagnosis to women with diethylstilbestrol exposure in utero, and that of the European Society of Human Reproduction and Embryology and the European Society for Gynaecological Endoscopy (ESHRE/ESGE) which does not provide specific cut-offs for thickened lateral walls and narrow uterine cavity and, thus, can result in misdiagnosis of a normal uterus as T-shaped based on subjective judgment of the lateral wall as thickened, the CUME classification provides detailed cut-offs to allow an accurate and reliable diagnosis of T-shaped uterus. However, the diagnosis of T-shaped uterus by the CUME or any other criteria does not imply that surgical intervention is justified in clinical practice1, 3. Our systematic review revealed that T-shaped uterus is a highly debatable morphological entity that is mostly diagnosed subjectively, and that there is a high risk of labeling a normal uterus as T-shaped. Moreover, it is uncertain whether T-shaped uterus is a congenital uterine anomaly or just a variant of normal morphology, and whether this condition has any impact on reproductive and obstetric outcomes1. Even though some studies have described ‘improved’ pregnancy rates after surgical treatment for T-shaped uterus, no study has been able to prove that this is a result of the intervention rather than regression towards the mean, as it is known that there is a higher probability of successful pregnancy after previous miscarriage rather than subsequent pregnancy loss. Hence, it should be highlighted that the diagnosis of T-shaped uterus implies only expectant management or use of this information for research purposes to increase reliable knowledge about this morphologic entity1, 3. The uterus is a hollow muscular organ, similar to a balloon with a thick wall, yet, a considerable part of the uterus is the endometrium, which lines the inside of the uterus. Indeed, the diagnosis of T-shaped uterus may be a result of myometrial contractions and the uterus may appear to be normal after repetition of the examination5. Also, these circular contractions may explain partly the OC-related diagnosis of T-shaped uterus described by Drs Leone and Cammarata. However, we speculate that it is possible that the T-shape of a uterine cavity is related to low endometrial volume (similar to an empty balloon) and that when the endometrial volume is higher, the cavity distends losing its T-shape (Figure 1). We also suggest that the prevalence of the condition is likely to be influenced by the phase of the menstrual cycle. Repeating the scan after detection of T-shaped uterus in order to rule out the potential effect of uterine contractions, and performing the diagnosis in the secretory phase may limit the overdiagnosis of T-shaped uterus3, 5. Also, in uncertain cases, we suggest that saline contrast sonohysterography (SCSH) is a more reliable tool for precise diagnosis. We speculate that the reproducibility of the diagnosis of T-shaped uterus at different timepoints is not high, and that variability in uterine muscle tension, assessment on different days of the menstrual cycle, examination before and after pregnancy and assessment at different ages would result in the appearance and disappearance of T-shaped uterus in the same individuals. We hope that use of the CUME classification and 3D ultrasound with repeat scans at different timepoints, as well as three-dimensional SCSH, will help increase our knowledge and provide trustworthy evidence about the natural history of this condition and prevent overdiagnosis. Sonologists should inform women diagnosed with a T-shaped uterus that reproductive medicine scientific societies do not recommend surgical correction, even in women with recurrent pregnancy loss6. The authors declare no competing interests.