Fig. 20.1
Septate uterus and its variants according to the new ESHRE/ESGE classification system (From Grimbizis et al. [14], with permission)
Septate uterus is further subdivided in partial septate (Class U2a) characterized by a septum partly dividing the uterine cavity above the level of internal cervical os and complete (Class U2b) characterized by a septum fully dividing the uterine cavity up to the level of internal cervical os (Fig. 20.1). Septate uterus could be also combined or not with cervical anomalies (septate cervix, double cervix unilateral cervical aplasia or cervical aplasia) and / or vaginal anomalies [14, 15] (Fig. 20.1). An interesting Class of the new ESHRE/ESGE classification system is the bicorporeal septate uterus (Class U3c); it is characterized by the combined presence of a fusion and abortion defect with an external midline fundal indentation of more than 50 % and a width of the uterine wall at that level of more than 150 % of the midline uterine wall thickness [14, 15] (Fig. 20.1). This is not a clear septate uterus but the septate element could be partially treated hysteroscopically.
Prevalence in the General and Selected Populations
The prevalence of septate uterus in selected populations grab the attention of several investigators since differences from that observed in the general population could highlight a possible clinical adverse effect on reproductive potential of women bearing this anomaly.
An initial effort has been published in 2001; according to this the prevalence of uterine anomalies has been found to be ~4 % in the general population, ~4 % in infertile patients and ~12 % in patients with recurrent pregnancy losses [1]. The indirect conclusion was that uterine anomalies and especially septate uterus could be responsible for an adverse pregnancy outcome but not for infertility. However, the major limitation of this review was the fact that, for the estimation of the pooled incidence in the various populations, the researchers took into account all the studies without any attention to the method used to diagnose the anomaly.
In order to treat this limitation and to draw more reliable conclusions, another group of investigators [2] tried initially to find out the diagnostic accuracy of the various available methods used for the diagnosis of uterine anomalies; any technique having >90 % accuracy in the diagnosis and differential diagnosis of the uterine anomalies is defined as high accuracy method. Endoscopy, hydro-sonography (HSG) and three-dimensional ultrasound (3D US) were found to be methods of high accuracy [2]. Taking into account only the high accuracy studies, the prevalence of uterine anomalies was found 6.2 % in the general population, 6.8 % in infertile population and 16 % in recurrent aborters [2]. Even this more sophisticated study failed to reveal a significant difference between general and infertile population highlighted again the difference in the recurrent aborters.
Three years later, another group has tried again to answer to the same question [3]; meanwhile more studies using high accuracy methods have been published. In their systematic review of high accuracy studies, the prevalence in the general population was found to be 5.5 % (CI 3.3–8.5 %), in infertile population 8 % (CI: 5.3–12 %), in recurrent aborters 13.3 % (CI: 8.9–20 %) and in women having infertility and recurrent pregnancy losses the impressive incidence of 24.5 % (CI: 18.3–32.8 %) [3]. It seems, therefore, that with the accumulation of more data and experience in the diagnosis of uterine anatomy with the newer available techniques, their incidence in infertile population became clearer that it could be higher although not yet statistically significant.
Another parameter studied for the estimation of the specific role of septate uterus, apart from that of uterine anomalies in general, on the reproductive potential of the women was the distribution and the incidence of the various anomaly’s types in the different populations.
Thus, in the review of Saravelos et al. [2] taking into account the high accuracy studies, the incidence of septate uterus in the general population was found to be 2 %, in infertile population 3.5 % and in recurrent aborters 5 %; the high incidence of uterine anomalies in the general population was mainly due to the presence of “arcuate” uteri. It could be concluded; therefore, that septate uterus could play a role both for the achievement and the evolution of pregnancy. The same tendency was observed for bicornuate uterus and the others more severe anomalies.
Chan et al. [3] observed a similar tendency for septate uterus. In their systematic review, the incidence of septate uterus in the general population was found to be 2.3 %, in infertile population 3 %, in recurrent aborters 5.3 % and patients with infertility and recurrent abortions 15.4 %; the high incidence of uterine anomalies in the general population was again found to be due to the presence of “arcuate” uteri.
It seems, therefore, that the prevalence of septate uterus is ~2 % in the general population, above 3 % in infertile patients and above 5 % in recurrent aborters; the existence of both infertility and pregnancy adverse outcome is associated with an incidence of ~15 %. This is an indirect indication that septate uterus could adversely affect the reproductive potential of the woman. It should be noted, however, that with the old AFS classification [5] the borders in the differential diagnosis between septate and arcuate uterus are not clear and the adoption of the new ESHRE/ESGE classification system could further elucidate this “hot” issue.
Impact on Fertility and Pregnancy Outcome
An initial effort to elucidate the impact of uterine anomalies, and more specifically of septate uterus on reproductive outcome, has been done by reviewing the available data from observational studies [1]. In unselected populations of women with uterine anomalies, the observed abortion rates ranged form 26 to 36 % which is twice higher to the ~15 % expected for the general population, the preterm delivery rates ranged from 14 to 18 % which is three times higher to the ~5 % observed in the general population, the term delivery rates ranged from 44 to 57 % and the live birth rates from 55 to 65 % [16–18].
An interesting observation was also that the expected poor pregnancy outcome seems to be exactly the same in the first and in the subsequent pregnancies thus excluding a possible favorable effect of the pregnancy on future prognosis of women bearing uterine anomalies, which was an old belief of the obstetricians [1, 16, 19]. Furthermore, by reviewing the available published data from ~500 pregnancies of ~200 women with septate uterus, the pooled observed abortion rate was even poorer reaching 44 %, the preterm delivery rate was 22 %, the term delivery rate 35 % and the live birth rate ~50 % [1]. The obvious conclusion of this group of researchers was that septate uterus is associated with poor reproductive outcome.
However, the major limitation of the prevalence and the observational studies is that they could provide only indirect evidence and not reliable conclusions. Those conclusions could be drawn only from a systematic review of comparative studies. Thus, in a systematic review of the available comparative studies [20], it was found that septate uterus was associated with a statistically significant decrease by 15 % in the conception rates (RR: 0.86, 95 % CI: 0.77–0.96), a statistically significant almost threefold increase in the abortion rates (RR: 2.89, 95 % CI: 2.02–4.14) and a statistically significant increase almost by twofold in preterm delivery rates (RR: 2.14, 95 % CI: 1.48–3.11) (Fig. 20.2).
Fig. 20.2
Reproductive outcome in women with septate and “subseptate” uterus: lower conception rates, higher abortion and preterm delivery rates (Data from Chan et al. [20])
Further to these efforts, in a more recent meta-analysis of the available studies [21], it was also found that the probability of conception, assisted or spontaneous, in women with congenital uterine anomalies (CUA) is decreased by ~15 % (RR: 0.86, 95 % CI: 0.74–1.00). Concerning the evolution of pregnancy, the probability of 1st and/or 2nd trimester miscarriages (RR: 1.68, 95 % CI: 1.31–2.17), preterm (<37 weeks) (RR: 2.21, 95 % CI: 1.59–3.08) and premature delivery (<34 weeks) (RR: 3.81, 95 % CI: 1.48–9.83) was found significantly increased. Furthermore, it is interesting that these researchers found that malpresentation at delivery (RR: 4.75, 95 % CI: 3.29–6.84), low birth weight babies (<2,500 g) (RR: 1.93, 95 % CI: 1.50–2.49), placental abruption (RR: 2.47, 95 % CI: 1.28–4.77) and perinatal mortality (RR: 2.43, 95 % CI: 1.34–4.42) were significantly increased in women with CUA as compared to women without CUA [21].
Another group of researchers [22] studied prospectively the conception rates of infertile patient with septate uterus and otherwise unexplained infertility after septum resection compared to those of couples with unexplained infertility only; conception rates were found to be almost double in the group of infertile patients who underwent septotomy, thus supporting that notion that the presence of septum adversely affects fecundity.
Although most of the comparative studies available in the literature and included in the pre-mentioned meta-analyses are still retrospective, all the evidence coming from the systematic evaluation of the prevalence, observational and comparative studies is in the same direction. It could be concluded, therefore, that the reproductive outcome is impaired in women with CUA.
Women with CUA and more specifically those with septate uterus have lower chances for conception although this needs still further investigation. Furthermore, those women experience between two and threefold increase in the probability of miscarriage and another two to threefold increase in the probability of preterm delivery and they have an additional adverse effect on fetus intrauterine growth, obstetric complications and perinatal mortality.
Techniques
Procedure Description (Surgical Steps)
Correction of septate uterus is nowadays feasible to be done in an easy and safe way with the use of operative hysteroscopy and aims at unifying the uterine cavity by cutting or resecting the septum. Treatment in cases of complete of partial septate uterus without any cervical involvement (ESHRE/ESGE Class U2C0V0) is started from the distal part of the uterine septum after clear visualization of the tubal ostia and continued upwards with progressive horizontal incisions in the midline. It is ended when a normal cavity is obtained and the hysteroscope could be moved freely from one tubal ostium to the other without any indentation (straight or slightly curved fundus with <50 % indentation at the midline level).
In cases of complete septate uterus associated with septate cervix (U2C1V0) two treatment alternatives has been proposed. The first one is the incision of the cervical septum with scissors followed by hysteroscopic resection of the intrauterine part. The second option is the incision of the uterine septum only leaving the cervical part intact in order to avoid cervical incompetence; in this treatment proposal, incision starts at the level of isthmus cutting the septum and unifying only the uterine cavity. In cases of complete septate uterus with double normal cervix (U2C2V0), the unification of the uterus cavity is the only treatment alternative and, thus, incision is always started from the level of uterine isthmus just above the internal cervical os.
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