I-38: Uterine Abnormally and Infertility

Congenital anomalies of the Müllerian ducts especially uterine abnormalities can affect negatively the different stages of fertility interfering with sperm migration, embryo implantation, normal placentation, fetal growth and achievement of a successful pregnancy. They are present in 2-10% of all women, three times greater in patients with recurrent pregnancy loss and lead to infertility and adverse pregnancy outcomes in 25% of cases. In general population mean incidence is 3-4%. In women with fertility problems, the incidence is slightly higher at 3-6%. In general, women with recurrent abortions have an incidence of 5-10%, with the highest incidence of Müllerian defects occurring in patients having third-trimester miscarriages (>25%). The most commonly reported anomalies are septate(35%),bicornuate (26%), arcuate (18%), , unicornuate (2.4-13%) , didelphys (10%). Beside pregnancy complications some uterine anomalies can lead to dysmenorrhea and endometriosis which could further lead to infertility issues. Anomalies mostly result from a defect of development or midline fusion of the Müllerian ducts, their failure to connect with the urogenital sinus or unsuccessful canalization during embryogenesis. These patients have usually normal ovaries and ovarian functions. The septate uterus results from failure of resorption of two fused ducts which leads to the formation of a partial or complete fibromuscular septum. Septate uterus is associated with the highest incidence of reproductive failure. Miscarriage rates up to 90% have been reported which are thought to be the result of poor blood supply in the septum. The preferred treatment modality is hysteroscopic metroplasty which can reduce the miscarriage rate to 14% with 80% term live birth rates compared to 3% before. Controversy exists regarding performing metroplasty in infertile women versus no treatment but in unexplained infertility and also in candidates for IVF with a septate uterus it can be beneficial. The arcuate uterus results from near-complete resorption of the uterovaginal septum. It is characterized by a small intrauterine indentation shorter than 1 cm and located in the fundal region. Compared with other Müllerian malformations, arcuate uterus is clinically benign despite an infrequent association with adverse obstetric outcomes, and may not affect reproductive outcomes. Nevertheless some studies in repeated IVF failures show beneficial effects of resection of the small septum which is thought to have a fibrous tissue structure and abnormal vascularization. The uicornuate uterus results when the Müllerian ducts fail to develop completely or partially. There are four types including unicornuate uterus with a communicating rudimentary horn, with a noncommunicating rudimentary horn, with or without a cavity and an isolated unicornuate uterus. They are usually associated with urinary tract and skeletal anomalies and also relatively poor reproductive results. The highest live birth rates are observed in women with a rudimentary horn with or without a cavity. The bicornuate uterus is the result of incomplete fusion in the Müllerian ducts. Most women have no fertility problem. There is higher mid-trimester pregnancy loss and preterm birth risk after conception.It rarely needs surgical treatment unless in patients with recurrent pregnancy loss,mid-trimester loss, premature birth and unexplained infertility. Uterus didelphys refers to the complete failure of fusion of the Müllerian ducts which results in duplication of the uterine corpus and cervix. It has a relatively good prognosis for fertility with some increase in adverse pregnancy outcomes. Uterine anomalies on the whole should be diagnosed and treated by different modalities not only to improve the patient’s fertility but to maintain the conception when it happens.