The outcome of singleton pregnancies after IVF/ICSI in women before and after hysteroscopic resection of a uterine septum compared to normal controls

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Abstract

Objective(s)

To evaluate the effect of hysteroscopic resection of a large uterine septum (Class V according to the American Fertility Society (AFS) classification) and of a small partial uterine septum (Class VI according to AFS classification or arcuate uterus) on the abortion rate in pregnancies after IVF and ICSI.

Study design

The retrospective matched control study included 31 women who conceived following IVF or ICSI before hysteroscopic resection of a large (12 women) or small partial (19 women) uterine septum and 106 women who conceived following IVF or ICSI after hysteroscopic resection of a large (49 women) or small partial (57 women) uterine septum. For each pregnancy in the study group, we found two consecutive pregnant control women from the IVF/ICSI registry who had a normal uterus and were matched for age, BMI, stimulation protocol and the use of IVF or ICSI and for various infertility causes. The abortion/pregnancy rate was the main outcome measure. Data on the septum length were obtained during hysteroscopic resection by comparing the length of the 1.4 cm long yellow tip of the electric knife to the length of the resected septum.

Results

The abortion rate before hysteroscopic metroplasty was significantly higher, both in women with a small partial septum (78.9% before resection vs. 23.7% in the normal controls, OR 12.08) and a large septum (83.3% before resection vs. 16.7% in normal controls, OR 25.00) compared to women with a normal uterus. After the surgery, the abortion rate was comparable to the abortion rate in women with normal uterus: in both women with a small partial and women with a larger septum.

Conclusion(s)

Similar to a large uterine septum, a small partial uterine septum is an important and hysteroscopically preventable risk factor for spontaneous abortion in pregnancies after IVF and ICSI.

Introduction

While a uterine septum (AFS Class V, according to the American Fertility Society (AFS) classification) [1] is accepted as an anomaly that often causes spontaneous abortion or premature delivery, the role of a small partial uterine septum is still debatable. In 1988, the AFS classification committee had difficulty deciding how to include a small partial septum. Because the uterus is externally unified, the anomaly could be classified as a form of a partial septate uterus. However, since in contrast to other malformations it appeared to behave benignly, it was thought that it should be classified separately as an arcuate uterus (AFS Class VI), until data can be generated that can be used to determine whether it should remain in the classification of abnormal uterine malformations or is a variant of normal anatomy. [1] According to this classification an uterus with a small partial septum and an arcuate uterus are synonyms.

Some authors still believe that a small partial septum is a variant of normal anatomy with no impact on reproduction [2], [3], [4]. On the other hand, data have been generated showing an increased incidence of spontaneous abortions [5], [6], [7] and of preterm births [8] in women with a small partial uterine septum, too.

It is difficult to evaluate the influence of a small partial uterine septum on the outcome of a pregnancy, since not all women with a small partial septum have reproductive problems and because a small partial septum often remains undiagnosed [9].

In the absence of clear evidence on how a small partial uterine septum influences natural pregnancy, we can examine assisted reproductive technology. Our previous reports have suggested that, as with a large uterine septum, a small partial septum increases the risk of spontaneous abortion [9], [10], [11]. In previous reports, we have compared the outcomes of pregnancies in the same women before and after hysteroscopic resections of the uterine septum. In order to test our findings further, we designed a matched control study that compares the abortion rates in pregnancies after IVF and ICSI. The abortion/pregnancy rates in women with a large uterine septum (AFS Class 5) and a small partial uterine septum (arcuate uterus or AFS Class 6) are compared to the abortion/pregnancy rates in women without uterine anomalies.

Section snippets

Materials and methods

The retrospective matched control study was conducted using data from the IVF/ICSI database of the University Women's Hospital, Ljubljana. The database includes detailed information related to IVF/ICSI procedures, as well as pregnancy outcomes.

We included in this study women who had conceived following an IVF/ICSI procedure during the period from January 1993 to December 2004. The study groups contained pregnant women after IVF or ICSI prior to and after hysteroscopic resection of a large or

Results

Of the original population of 159 women before or after hysteroscopic resection of a large or small partial septum, with a biochemical diagnosis of pregnancy, 137 women were included in the study groups after excluding extrauterine pregnancies, multiple pregnancies and cases with an empty gestational sac. There were 31 pregnancies before hysteroscopic resection of a large or a small partial uterine septum and 106 pregnancies after the surgery. They were compared to 274 pregnancies in matched

Discussion

Despite the known classification of Mullerian anomalies [1], differentiation between a small partial uterine septum or arcuate uterus and an incomplete septate uterus is subjective and quantification is lacking [13].

To our knowledge, from the literature we have researched, authors have used three methods to quantify the septum. The first is ultrasound measurement and comparing the mean cornual myometrial thickness with the fundal midsagittal myometrial thickness. The second method was

Acknowledgements

The authors would like to thank to coworkers: Mr. Sašo Drobnič MD, Mr. Andrej Vogler MD, Ph.D., Mr. Branko Zorn MD, Ph.D., Mrs. Lili Bačer-Kermavner B.Sc., Mrs. Jerneja Kmecl B.Sc., Mrs. Brigita Valentinčič dipl. biol., Mrs. Jožica Mivšek biol., Mrs. Blanka Gradišek and Mrs. Andreja Peterlin and especially to Mr. Martin Cregeen and Mrs. Mojca Pirc for language editing. The work was supported by the Ministry of Education, Science and Sports and by the Ministry of Health of the Republic of

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