Where is endometrial cavity

Meanwhile, another study found that hydrosalpinx had no adverse effect on embryo development There is an opinion that ECF, which is secreted by the genital tract and does not arise from the fallopian tube, has no effect on embryo implantation 6. Transient ECF is not associated with hydrosalpinx or any identifiable pelvic pathology and is thought to have no negative effect on the IVF pregnancy rate Our data showed that the toxic effects of hydrosalpinx on embryos and gametes may further aggravate the adverse effects of uterine effusion, which consistent with previous studies There are two different views about the ingredients that may be contained in ECF.

Some studies have speculated that the presence of ECF dilutes putatively beneficial factors in the uterus following ET There are also changes in the expression levels of genes associated with uterine receptivity e.

However, other studies suggest that growth factors from hydrosalpinx fluid might play a positive role during implantation 11 , The clinical pregnancy and live birth rates of patients with ECF were significantly worse than those of the controls. We also explored the impact of ECF on obstetric outcomes.

The main indices of obstetric outcome including gestational age, birth weight, fetal gender, dysplasia, and number of fetuses showed no significant differences between the groups.

After implantation, the environment in the uterus changes accordingly. The formation of pinopodes promotes the absorption of fluid in the uterine cavity. This may be the mechanism by which uterine effusion does not continue to affect the growing embryo. We also found a higher incidence of gestational diabetes in the ECF group, which is considered to be one of the causes of polyhydramnios The results of previous studies have shown that endometrial fluid contains significantly different protein compositions during the implantation and non-implantation cycles, and that endometrial fluid during the non-implantation cycle increases inflammation and impaired glucose metabolism We speculate that persistent uterine effusion may itself be an indicator of a non-implantable endometrial state.

However, the possible causal relationship between short-term changes in blood glucose levels and the accumulation of ECF requires further study. To our knowledge, this is the first report on the relationship between ECF and such obstetric outcomes. Another study developed a flow chart for how to deal with ECF in different situations; briefly, cryopreservation of the embryos should be considered when there is a large amount of ECF or when this issue is combined with a complex intrauterine environment Clearly, further research into the treatment of ECF is needed.

According to our study, we believe the presence of ECF is an indicator of adverse pregnancy outcomes even when the amount is less than 3. Our previous experience shows that in addition to transvaginal sonographic ECF aspiration, moderate curettage of the uterus is also effective.

We also found that some Chinese traditional herbal medicines such as Leonurus cardiaca might help with the absorption of effusions in some cases. We recommend processing ECF immediately to avoid postponing ET, which places economic and psychological pressures on patients.

There were some limitations in our research. Firstly, during the follow-up, some patients could not be contacted for various reasons or could not provide accurate and useful information after being contacted, including some patients diagnosed with ECF in the early phase of data collection. This missing information might have affected the statistical evaluation of the results. Also, in terms of the amount of uterine effusion, there was only one approximate value in the patient information recorded by our hospital, and there was no accurate numerical value to analyze the relationship between the volume of ECF and pregnancy outcomes in a systematic manner.

These limitations need to be improved in future research. The clinical significance of this issue is far-reaching, and should arouse the attention of clinicians and be studied extensively. The mechanism of ECF accumulation, as well as the relationship between its amount, timing, and pregnancy outcomes requires further in-depth studies.

Thus, the presence of ECF might be an indicator for the occurrence adverse pregnancy outcomes. The decision to treat uterine effusions should accord with individual patient conditions. The mechanism of ECF production and treatment requires further research. The authors thank Elsevier Language Editing Services for help in revising the manuscript. We are very grateful to our patients and all participants for their involvement in the process of data collection.

We thank Dr. The authors have no conflicts of interest to declare. Ethical Statement : The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Figure 1 Experimental flow chart. Using this information and known endometrial cavity volumes and lateral and vertical dimensions, it is possible to calculate the anteroposterior AP dimensions and get a complete evaluation of all possible dimensions of the endometrial cavity.

These are singular observations and not part of any other study. The AP dimensions of the endometrial cavity of the uterus were calculated using the formula for the volume of the prolate ellipsoid to complete a three-dimensional picture of the endometrial cavity. Calculations confirm ultrasound imaging which shows large variations in cavity size and shape.

Known cavity volumes and length and breadth measurements indicate that the AP diameter may vary from 6. These measurements confirm the difficulty of getting a fixed-frame intrauterine device IUD to accommodate to a space of highly variable dimensions.

This is especially true of three-dimension IUDs. A one-dimensional frameless IUD is most likely to be able to conform to this highly variable space and shape. The endometrial cavity may assume many varied prolate ellipsoid configurations where one or more measurements may be too small to accommodate standard IUDs. A one-dimensional device is most likely to be able to be accommodated by most uterine cavities as compared to two- and three-dimensional devices.

These materials were rigid and difficult to insert and their geometrical shape would have caused significant to extreme distortion of the endometrial cavity. This was naturally accompanied by pain, bleeding, and discomfort, and even infection. The plastics revolution of the s helped Lippes design the Lippes Loop IUD which was made of polyethylene impregnated with barium sulfate. It was malleable and would retain its shape and could be withdrawn into an inserter tube and injected into the endometrial cavity where it would resume its original shape.

These dimensions are too large for the dynamic uterine cavity in vivo. Although the insertion procedure was much more tolerable than that of the earlier devices, the experience during subsequent usage was still problematical due to distortion of the uterine cavity by the oversized loops.

This was true even of the smallest size. The greater the size of the device, the greater the amount of MBL. A frame is like a skeleton — it gives stability and the ability to withstand collapsing and gravitational forces, which is why vertebrates have them.

Invertebrates, like the octopus, do not have skeletons frames and cannot withstand these forces but can resist compressive forces by molding their bodies to fit very small and changing spaces. In order to successfully occupy a hollow muscular organ like the uterus, an IUD does not need to be able to resist collapsing and gravitational forces — it needs to be able to adapt to small liquid potential spaces. An IUD needs to be able to fit and adapt to these small liquid filled spaces which are continually changing with uterine muscular activity and contractions.

Ideally, it needs to be able to mold and change its shape effortlessly to that of the endometrial cavity; in other words, it ideally really needs to be frameless and without a skeleton. Just how small and changeable is the endometrial cavity? The uterus itself most closely approximates the geometrical shape of a prolate ellipsoid.

Additionally, since we can eliminate the cervix and the cervical canal which are not part of the endometrial cavity , the endometrial cavity itself can be assumed to also take the shape of a prolate ellipsoid, and in fact removal of the cervix ensures that the cavity more closely approximates a prolate ellipsoid than does the whole uterus. The volume of a prolate ellipsoid is given by the following formula:.

Endometrial cavity volume has been measured and varies between 5 and 10 mL. Transfundal endometrial cavity width varies widely from as little as 7 mm in very narrow cavities to the more usual 22—34 mm depending on parity.

There is a wide variation in uterine measurements, but it is possible to calculate boundary values which will accommodate most sizes and volumes. Table 1 gives representative values for a range of volumes and for a range of endometrial cavity widths and lengths. It was obtained by using extreme values of volume and lateral longitudinal uterine cavity measurements to calculate AP dimensions using the prolate ellipsoid formula given in the previous section.

For example, in a low-volume endometrial cavity of length 40 mm and width 38 mm, the equation shows that the AP diameter would be 6 mm. During uterine contraction, the endometrial cavity is distorted even further, which can reduce the value of these dimensions.

An IUD which has 2 or 3 dimensions needs a large enough size to anchor but should not be so large as to cause problems. The external longitudinal and internal circular muscle fibers of the uterus are a continuation of the tubal muscle fibers. In addition, there are circular fibers which sweep around the uterus in both clockwise and counterclockwise directions.

This arrangement of the muscle fibers means that the endometrial cavity dimensions will change in all three axes L, W, AP , ie, there will be three-dimensional change in the endometrial cavity. While not all IUD-related problems are related to dimensional incompatibility between the IUD and the endometrial cavity, it is likely that mismatch between the size of the IUD and the uterine cavity is certainly not optimal and can only be detrimental to device performance.

This is because it would have to be compatible with the length, width, and AP diameter of the endometrial cavity. Figure 1 shows a severely distorted uterine cavity due to a manifest discrepancy between the IUD and the endometrial cavity. Severe distortion causing bleeding and pain 13 due to incompatibility of the large T-shaped IUD and the narrow uterine cavity.

Notes: Forceful uterine contractions displace the IUD in the cervical canal prior to expulsion. Figure provided courtesy of Dr Wildemeersch. Our previous models have only examined static two-dimensional changes. While it is difficult for framed devices to accommodate to changing lateral and sometimes linear dimensions, it is virtually impossible for them to simultaneously adapt to changing AP dimensions as well, since they would be subject to changes of force in three dimensions.

This produces a three-dimensional squeeze which, at worst, is possibly responsible for secondary perforation 15 but leads to the user experiencing pain and discomfort, often accompanied by embedment Figure 3. Transverse arms embedded in the side wall of the uterus caused by disharmony of the IUD with the uterine cavity. There are two main limitations to the dimensional approach toward IUD design. First, the size of the endometrial cavity is very variable, so an IUD of any one size is not able to fit a wide range of cavities.

Second, the uterus will sometimes show tolerance to what appear to be ill-fitting devices. This technique requires insertion training and is tissue invasive. Evidently, a one-dimensional frameless IUD that is self-adherent to the endometrial cavity would appear to be optimal, but this may not be technically feasible.

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