How Uterine Anomalies Can Affect Fertility
Congenital uterine anomalies are abnormal shapes of the uterus that develop before birth. The uterus forms as two primitive structures called the Mullerian ducts that fuse together to form the fallopian tubes, uterus, and upper vagina between weeks 6 and 20 of fetal development. When a uterus develops differently it is called a uterine anomaly.
There are several types of congenital uterine anomalies. The anomalies are characterized by the American Society of Reproductive Medicine (ASRM) based on the Mullerian duct development. Types of congenital uterine anomalies include:
- Septate: a normal external uterine surfaces but two endometrial cavities
- Bicornuate: an abnormal, indented external uterine surface and two endometrial cavities
- Arcuate: a normal external uterine surface with a 1 cm or less indentation into the endometrial cavity
- Unicornuate: only one half of the uterus has developed
- Didelphys: the two halves of the uterus remain separate
The septate uterus and bicornuate uterus are the most common anomalies, while the arcuate uterus is considered a variation of normal development.
The uterus is responsible for many of the crucial steps in the process of reproduction, including sperm migration, embryo implantation, fetal nourishment, development and growth, and, finally, labor. As a result, any malformations can have an impact on reproductive outcomes. In fact, up to 25% of women who have had recurrent miscarriages and/or deliveries of premature babies have been diagnosed with a uterine anomaly. Yet, it should be noted that many women with uterine anomalies do experience normal obstetric outcomes. While the adverse effect of uterine anomalies on pregnancy is well-documented, the role of these anomalies on fertility remains elusive and evidence is lacking. There are, however, several theories that have been proposed to explain the effects of congenital uterine anomalies on fertility.
Embryo implantation is affected by the shape and integrity of the uterine cavity. If a congenital uterine anomaly is present, this can possibly affect the ability of an embryo to implant, resulting in pregnancy loss. Additionally, several studies have suggested that the effects on fertility caused by uterine anomalies could be mediated through other infertility factors. For example, patients with uterine anomalies are more likely to have infrequent or no periods. They are also more likely to have endometriosis.
Because evidence on the effect of uterine anomalies on fertility remains incomplete, it is important that infertile women who are found to have a congenitally malformed uterus be counseled and offered options including surgical treatment depending on the particular anomaly and their reproductive history. For example, women with a septate uterus can undergo surgery to correct the malformation, whereas women with bicornuate, unicornuate, or didelphic uteri rarely require surgical treatment.
Individuals who are having trouble getting pregnant and want to explore the possibility of a uterine anomaly should contact RMA of New York to make an appointment. The physicians at RMA of New York will work with patients to identify an accurate diagnosis and subsequent treatment plan that aligns with patients’ family building goals.