Reproductive Outcomes in Women With Uterine Anomalies

Paul C. Lin, M.D.

In This Article

Arcuate Uterus and Septate Uterus

Pregnancy outcomes are very similar when compared with known historical controls.[1,2,11] Not all the studies included data on live birth rates, preterm delivery rates, and ectopic rates ( Table 1 ). In two of the three studies that looked at reproductive outcome of the arcuate uterus, Acien[1] showed significant reduction in liveborn rates and increase in miscarriage rates. The study is vague on the difference between the arcuate uterus and the uterine septum. Therefore, interpretation of the results is difficult. Another study showed that a septal length <1 cm has a similar reproductive outcome to septi that were completely resected.[12] By definition, an arcuate uterus has an intrauterine indentation of <1 cm. Overall, the arcuate uterus probably does not have an impact on reproduction and obstetrical outcomes.

The impact of a septate uterus is most apparent on miscarriages. Of patients with a uterine septum, 25.5% had a miscarriage, and surgical treatment is most effective.[2] Data on the reproductive outcome are abundant. Table 1 includes a compilation of the multiple studies that looked at untreated septate uterus.[2,13] Kupesic[13] compiled 13 studies looking at uterine septum and reproductive outcome but did not include data on live birth rates and ectopic rates, unfortunately. The septate uterus has a major impact on pregnancy retention, with a signficant chance of miscarriage. The heterogeneity of subjects in each study is apparent, as live birth rates can be a respectable 58.1%.

The impact of a uterine septum on infertility is less clear. Two observational studies of a total of 47 infertile subjects found 53.2 % achieved pregnancy after hysteroscopic resection. No control group or symptomatic untreated subjects with septate uteri were included.[14,15] The diagnosis is usually found on a HSG during the standard infertility evaluation. Differentiation between the uterine septum and the bicornuate uterus cannot be made definitively with the HSG alone. Further evaluation of the fundal contour must be done with laparascopy, MRI, or US because therapy is very different.

The incidence of both complete and partial uterine septi is 33.6%, and it is the most common uterine anomaly.[2] Therapy originally involved wedge resection of the uterine septum, but because of improved surgical equipment and better optics, hysteroscopic resection is fairly routine and technically simple to perform. It is, in fact, an incision rather than an excision of the septum. Pregnancy outcome has been shown to significantly improve. A retrospective cohort study of women undergoing hysteroscopic resection of a uterine septum demonstrated a significant decrease in miscarriage rates from 80% to 17% and an increase in the live birth rates from 18% to 91%.[14]

Poor pregnancy outcome is believed, in theory, to be due to the septum's poor implantation environment. The septum provides a scanty vascular supply for the implanting embryo because of disruption by the septum of orderly arranged vessels in the intermediate myometrial layer of the uterus.[16] A small study looked at the site of implantation of pregnancies in subjects with uterine septum and found that the 8 of 12 pregnancies that miscarried were found on the uterine septum. The other 4 pregnancies that did not miscarry were on the lateral wall of the uterus.[17] Despite the poor numbers, this study confirms what we suspect: implantation of pregnancy that occurs on the uterine septum has a high likelihood of miscarriage.

Because of its technical simplicity and significant impact on improving reproductive capacity, I advocate surgical removal of the uterine septum, especially in women diagnosed with recurrent pregnancy losses. Resection may also be considered in infertile couples where no other obvious etiology is apparent.


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