Reproductive Implications and Management of Congenital Uterine Anomalies: Scientific Impact Paper No. 62

Congenital uterine anomalies (CUAs) are malformations of the uterus (womb) that develop during fetal life. When a female baby is in her mother's uterus, her uterus develops as two separate halves from two tubular structures called Müllerian ducts, which fuse together before she is born. Anomalies that occur during the baby's development can be variable, from complete absence of the uterus through to more subtle anomalies, which are classified into specific categories. While conventional ultrasound is good at detecting CUAs, 3D ultrasound is used to confirm a diagnosis. If a complex uterine anomaly is suspected, additional investigations may be used, including MRI scanning, laparoscopy (where a camera is inserted into the cavity of the abdomen) and/or hysteroscopy (where a camera is placed in the uterine cavity). As there can be a link between CUAs and anomalies of the kidney and bladder, scans of these organs are also usually requested. Although CUAs are present at birth, adult women typically do not have any symptoms, although some may experience painful periods. Most cases of CUA do not cause difficulties in becoming pregnant, and the outcome of pregnancy, in most cases, is good. However, these uterine anomalies are often discovered during investigations for infertility or miscarriage. Moreover, depending upon the type and severity of CUA, there may be increased risk of first and second trimester miscarriages, preterm birth, fetal growth restriction (smaller and lighter babies for the stage of pregnancy), pre-eclampsia (development of high blood pressure and protein in urine after the 20th week of pregnancy) and fetal malpresentation (baby not facing head-first down the birth canal) at birth. Surgical treatment may be considered for those who have had recurrent miscarriages and have a septate uterus, i.e. the uterine cavity is divided by a partition. In this case, surgery may reduce the chances of miscarriage. However, women should be informed that there is inconclusive and conflicting evidence regarding the improved likelihood of live births in this context. Further evidence from large randomised controlled trials are required to provide conclusive evidence-based recommendations for surgical treatment for septate uterus. Surgical treatment for other types of CUAs is not usually recommended as the risks outweigh potential benefits, and evidence for any benefits is lacking. Women with CUAs may be at an increased risk of preterm birth even after surgical treatment for a septate uterus. These people, if suspected to be at an increased risk of preterm birth based on the severity of CUA, should be followed up using an appropriate protocol for preterm birth as outlined in UK Preterm Birth Clinical Network Guidance.