The role of sonographic endometrial patterns and endometrial thickness in the differential diagnosis of ectopic pregnancy

Conventional and modern markers of pregnancy of unknown location: Update and narrative review

Pregnancy of unknown location (PUL) is a temporary pathologic or physiologic phenomenon of early pregnancy that requires follow up to determine the final pregnancy outcome. Evidence indicated that PUL patients suffer a remarkably higher rate of adverse pregnancy outcomes, represented by ectopic gestation and early pregnancy loss, than the general population. In the past few decades, discussion about PUL has never stopped, and a variety of markers have been widely investigated for the early and accurate evaluation of PUL, including serum biomarkers, ultrasound imaging features, multivariate analysis, and the diagnosis of ectopic pregnancy based on risk stratification. So far, machine learning (ML) methods represented by M4 and M6 logistic regression have gained a level of recognition and are continually improving. Nevertheless, the heterogeneity of PUL markers, mainly caused by the limited sample size, the differences in population and technical maturity, etc., have hampered the management of PUL. With the advancement of multidisciplinary integration and cutting-edge technologies (e.g. artificial intelligence, prediction model development, and telemedicine), novel markers, and strategies for the management of PUL are expected to be developed. In this review, we summarize both conventional and novel markers (represented by artificial intelligence) for PUL assessment and management, investigate their advancements, limitations and challenges, and propose insights on future research direction and clinical application.

An endometrium of type C along with an endometrial thickness of < 8 mm are risk factors for ectopic pregnancy after stimulated cycles with fresh embryo transfer

BACKGROUND

The study investigated whether specific ultrasonographically observed endometrial features (including endometrium type and thickness) were linked to ectopic pregnancy after stimulated cycles with fresh embryo transfer.

METHOD

Of 6246 pregnancy cycles after fresh embryo transfer, 6076 resulted in intrauterine pregnancy and 170 in ectopic pregnancy. The primary outcome of the study was ectopic pregnancy, with the main variables being endometrium type and endometrial thickness. Univariate and subsequent multiple-stepwise logistic regression analyses were used to identify the risk factors of ectopic pregnancy.

RESULTS

1. Compared with patients with an endometrial thickness ≥ 8 mm, the adjusted odds ratio for those with an endometrial thickness < 8 mm was 3.368 (P < 0.001). The adjusted odds ratio for women with a type-C endometrium was 1.897 (P = 0.019) compared with non-type C. 2. A larger dose of gonadotropin used during controlled ovarian hyperstimulation was a protective factor against ectopic pregnancy (P = 0.008). 3. The GnRH antagonist protocol (P = 0.007) was a risk factor for ectopic pregnancy, compared with the use of GnRH agonists.

CONCLUSION

(1) An endometrial thickness < 8 mm coupled with a type C endometrium significantly increased the risk of ectopic pregnancy after fresh embryo transfer. (2) A thin endometrial thickness and a type C endometrium could be further related to an abnormal endometrial receptivity/peristaltic wave. (3) Patients at a high risk of ectopic pregnancy should therefore be given special attention, with early diagnosis during the peri-transplantation period may assist in the prevention of ectopic pregnancy.

The correlation between endometrial thickness and the criteria for MTX treatment for ectopic pregnancy

Ectopic pregnancy (EP) occurs in approximately 2% of all pregnancies. A common method of treatment is methotrexate therapy, considered in haemodynamically stable patients. Endometrial thickness has been investigated as a tool for diagnosing EP. The objective of this study was to evaluate the association between endometrial thickness and the criteria for MTX treatment, in an attempt to facilitate outcome prediction. We retrospectively collected data from records of patients diagnosed with EP between 2012 and 2014 including information regarding the mode of treatment and outcome. The endometrial thickness was compared between cases that met the criteria for MTX treatment and those who did not. Of 267 cases of EP that were reviewed, 108 patients were treated with MTX. The MTX treatment success rate was 88%. Endometrial thickness was found to be significantly and inversely associated with criteria for MTX treatment. In conclusion, an association was found between the endometrial thickness and the criteria for selection of MTX treatment for EP. This may be a useful tool in treatment selection for EP.Impact StatementWhat is already known on this subject? Transvaginal sonography along with β-human chorionic gonadotrophin (β-hCG) monitoring is the standard for evaluation of suspected ectopic pregnancy (EP). The most specific sonographic finding for EP is the presence of a live extra uterine pregnancy. In research conducted with the purpose of finding intrauterine sonographic findings associated with EP, this condition has been shown to be correlated with a thinner endometrial lining, compared with that of an intrauterine pregnancy.What the results of this study add? The results of this study add information on the subject of methotrexate treatment success rates in correlation with the endometrial thickness.What the implications are of these findings for clinical practice and/or further research? The findings of this study contribute to the process of treatment selection for ectopic pregnancy by emphasising the association between a thick endometrium and the lower success rates of MTX treatment.

Use of haemostatic gel in the management of cervical pregnancy: a case report

PURPOSE

This case report aimed to describe haemostatic agents with systemic methotrexate (MTX) as an effective management for cervical pregnancy with bleeding.

CASE PRESENTATION

A 34-year-old nulligravida patient was referred due to vaginal spotting and lower abdominal discomfort, and was diagnosed with a cervical pregnancy at 6 weeks of gestation. The patient was treated with a multi-dose MTX regimen, and the bleeding was successfully controlled with haemostatic agents, which were applied at the bleeding site of the cervix. After completion of MTX treatment, beta human chorionic gonadotropin (β-hCG) decreased to undetectable range. Furthermore, patients could preserve her uterus and maintain fertility.

CONCLUSION

Haemostatic agents can be regarded as an effective option for vaginal bleeding due to cervical pregnancy.

Endometrial thickness as a predictor of ectopic pregnancy in 1125 in vitro fertilization-embryo transfer cycles: a matched case-control study

PURPOSE

The ectopic pregnancy (EP) rate after in vitro fertilization-embryo transfer (IVF-ET) is higher than after spontaneous conception. The reason for the increased risk of EP is not clear. We aimed to determine the risk factors associated with EP in patients undergoing IVF-ET.

METHODS

This was a 1:4 matched case-control study that enrolled 225 EP patients and 900 matched intrauterine pregnancy patients from the ART center of Northwest Women's and Children's Hospital from January 2014 to April 2018. Conditional logistic regression was used to analyze the association between risk factors and EP, and a receiver-operating characteristic (ROC) curve was generated for the predictors of EP.

RESULTS

Our findings showed that tubal factor (OR 1.61; 95% CI 1.12-2.31) and pelvic surgery other than cesarean section (OR 2.04; 95% CI 1.26-3.29) were associated with a higher risk of EP (p = 0.001). An endometrial thickness > 12 mm prior to embryo transfer (OR 0.27; 95% CI 0.13-0.56) and the number of transferable embryos (OR 0.71; 95% CI 0.65-0.78) were protective factors against EP (p < 0.001). The other factors did not have a significant effect on the probability of developing ectopic pregnancy. The area under the curve of the endometrial thickness and the number of transferable embryos for EP prediction were higher than those for tubal factor and pelvic surgery other than cesarean section.

CONCLUSIONS

An endometrial thickness > 12 mm is a strong protective factor against ectopic pregnancy. Attention should be paid to women with specific characteristics who have undergone IVF-ET.

Effect of endometrial thickness on ectopic pregnancy in frozen embryo transfer cycles: an analysis including 17,244 pregnancy cycles

OBJECTIVE

To investigate whether endometrial thickness (EMT) influences the incidence of ectopic pregnancy (EP) in frozen embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SETTING

Academic tertiary-care medical center.

PATIENT(S)

A total of 16,556 patients were enrolled between January 2010 and December 2017, comprising 16,701 intrauterine, 488 ectopic, and 45 heterotopic pregnancy cycles after FET.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

EP was the primary outcome. EMT was the main measured variable. Data were analyzed with the binary logistic general estimating equations model to calculate the adjusted odds ratio (aOR) for EP.

RESULT(S)

After adjusting for confounders, EMT remained statistically significant as an independent risk factor for EP. Compared with women with an EMT of ≥14 mm, the aORs for women with EMT in the ranges 7-7.9, 8-9.9, and 10-11.9 mm were 2.70 (95% confidence interval [CI], 1.65-4.40), 2.06 (95% CI, 1.33-3.20), and 1.66 (95% CI, 1.07-2.58), respectively. Hormone replacement treatment for endometrial preparation during FET increased the risk of EP after adjustment for confounding variables.

CONCLUSION(S)

EMT is inversely proportional to EP rate in FET cycles and is therefore a potential quantitative marker of endometrial receptivity and uterine contractibility in an FET cycle. The predictive validity of EMT value must be evaluated in further studies.

The diagnostic role of the β-hCG discriminatory zone combined with the endometrial pattern for ectopic pregnancy in Chinese women

Previous studies have regarded the discriminatory serum β-hCG zone (DSZ) as a valuable tool for the diagnosis of ectopic pregnancy (EP). However, the wide range of the DSZ makes achieving a clinical diagnosis of EP difficult, and these reports do not indicate whether the DSZ is suitable for an EP diagnosis in Chinese women. Several studies have indicated that the endometrial pattern in patients with EPs is different from that in patients with intrauterine pregnancies (IUPs). The aims of this study were to define the DSZ cutoff value for Chinese women, test whether the endometrial pattern is a suitable predictor for EP, and assess the diagnostic value of these indicators. We enrolled participants with IUPs or EPs with abdominal pain and/or vaginal bleeding, and serum β-hCG level measurements and transvaginal ultrasound (TVS) were performed to assess the diagnostic value of the indicators for EP. The sensitivity and specificity for identifying an EP were improved by combining the DSZ, endometrial thickness and trilaminar pattern indexes. The results of this study might be helpful toward providing further options for the diagnosis of EP, especially for patients without hemoperitoneum or colporrhagia.

Evaluation of sonographic endometrial patterns and endometrial thickness as predictors of ectopic pregnancy

OBJECTIVE

To evaluate whether endometrial patterns and thickness could be used for the prediction of ectopic pregnancy (EP).

METHODS

A prospective study was conducted in a center in India between October 2007 and December 2008. It included 100 women with an early pregnancy confirmed by urine pregnancy testing but for whom an intrauterine gestational sac was not visualized on transvaginal ultrasonography (TVS). The women were divided into an EP group and an intrauterine pregnancy (IUP) group depending on the final diagnosis. The endometrial pattern and endometrial thickness were determined by TVS. Sensitivity and receiver operating characteristic curve analyses were performed to determine the predictive value.

RESULTS

A heterogenous hyperechoic or trilaminar endometrial pattern was noted in 53 (77%) of 69 women in the EP group and 12 (39%) of 31 in the IUP group, and a homogenous hyperechoic pattern in 3 (4%) women in the EP group and 13 (42%) in the IUP group. An endometrial thickness of less than 9.8 mm was predictive of EP (P<0.001), and an endometrial pattern other than homogenous hyperechoic had a sensitivity and a negative predictive value of 81.3% for the diagnosis of EP.

CONCLUSION

Evaluation of endometrial thickness and pattern by TVS helps to identify women with a pregnancy of unknown location for close supervision.

Accuracy of first-trimester ultrasound in diagnosis of tubal ectopic pregnancy in the absence of an obvious extrauterine embryo: systematic review and meta-analysis

OBJECTIVES

To determine the accuracy of ultrasound in the diagnosis of a tubal ectopic pregnancy in the absence of an obvious extrauterine embryo.

METHODS

This was a systematic review conducted in accordance with the PRISMA statement and registered with PROSPERO. We searched MEDLINE, EMBASE and The Cochrane Library for relevant citations from database inception to July 2014. Studies were selected in a two-stage process and their data extracted by two reviewers. Accuracy measures were calculated for each ultrasound sign, i.e. empty uterus, pseudosac, adnexal mass and free fluid in the pouch of Douglas, alone and in various combinations. Individual study estimates were plotted in summary receiver-operating characteristics curves and forest plots for examination of heterogeneity. The quality of included studies was assessed.

RESULTS

Thirty-one studies including 5858 women were selected from 19,959 citations. Following meta-analysis, an empty uterus on ultrasound was found to predict an ectopic pregnancy with a sensitivity of 81.1% (95% CI, 42.1-96.2%) and specificity of 79.5% (95% CI, 68.9-87.1%). The corresponding performance of the pseudosac, adnexal mass and free fluid were: 5.5% (95% CI, 3.3-9.0%) and 94.2% (95% CI, 75.9-98.8%); 63.5% (95% CI, 48.5-76.3%) and 91.4% (95% CI, 83.6-95.7%); and 47.2% (95% CI, 33.2-61.7%) and 92.3% (95% CI, 85.6-96.0%), respectively.

CONCLUSION

Visualization of an empty uterus, adnexal mass, free fluid or a pseudosac has poor sensitivity for the diagnosis of a tubal pregnancy when an obvious extrauterine embryo is absent, but it has good specificity. We can therefore infer that ultrasound is more useful for 'ruling in' a tubal pregnancy than 'ruling out' one. However, the findings were limited by the poor quality of some included studies and heterogeneity in the index test and reference standard.

First-trimester diagnosis and management of Cesarean scar pregnancies after in vitro fertilization-embryo transfer: a retrospective clinical analysis of 12 cases

BACKGROUND

Although Caesarean scar pregnancy (CSP) is rare, it can cause life-threatening complications. The increasing rate of Cesarean delivery plus rapid development of in vitro fertilization-embryo transfer (IVF-ET) may increase the occurrence of CSP as well as the ratio of heterotopic CSP (HCSP)/CSP. Therefore, early diagnosis and management of CSP are necessary to avoid serious complications. And the purpose of this article is to evaluate the importance and feasibility of the first-trimester diagnosis and management of CSP after IVF-ET.

METHODS

All the 12 cases were secondary infertility patients who had a history of Cesarean section and underwent IVF-ET in our reproductive center. All cases with CSP were diagnosed using transvaginal color Doppler sonography (TVS). Medical, surgical and expectant managements were implemented, and the management results were traced.

RESULTS

Patients with CSP (n = 12) were diagnosed from January 2011 to April 2015, 6 (50 %) of which were HCSP. The prevalence of CSP was 1:1688 pregnancies. The gestational age ranged from 5 + 3 to 7 + 4 weeks in all CSP, and from 5 + 6 to 7 + 4 weeks in HCSP at diagnosis. Five patients received successful surgical treatment. The success rate of medical and expectant management was 50 % (1/2) and 100 % (5/5), respectively. One patient with failed medical management needed an emergency laparotomy to evacuate CSP. The uterus was preserved in all 12 patients.

CONCLUSIONS

The Caesarean section and IVF-ET may increase the ratio of HCSP/CSP. TVS is a noninvasive and effective tool for use in diagnosing CSP. CSP should be carefully excluded in patients who have had a history of Caesarean section. Early diagnosis of CSP in the first trimester may contribute towards the preservation of uterus as well as intrauterine pregnancy (IUP) in HCSP.

Avoiding misdiagnosing an early intrauterine pregnancy as an ectopic pregnancy

In women at risk for an ectopic pregnancy, every effort should be made to exclude the presence of an intrauterine pregnancy before embarking on an irreversible treatment for ectopic pregnancy. The diagnosis of ectopic pregnancy, unless directly visualized with transvaginal ultrasound, is made with the exclusion of an intrauterine pregnancy. Measurement of human chorionic gonadotrophin and progesterone levels, and transvaginal ultrasound are the tools used to evaluate early pregnancy. In women at risk for an ectopic pregnancy, every effort should be made to exclude the presence of an intrauterine pregnancy before embarking on an irreversible treatment course. Methotrexate is an antimetabolite that inhibits DNA synthesis and repair and cell replication. It is administered to ostensible destroy a pregnancy, especially ectopic pregnancies. When administered to an intrauterine pregnancy, embryonic death and missed abortion is the most common result, but early embryos that survive this exposure are likely to have multiple anomalies. The mistaken administration of methotrexate to an intrauterine pregnancy is made because of misinterpretation of the discriminatory zone of human chorionic gonadotropin (hCG), misinterpretation of early hCG serum levels, misinterpretation of early transvaginal ultrasound images, and failure to clinically correlate hCG levels and ultrasound findings.

Can sonographic endometrial pattern be an early indicator for tubal ectopic pregnancy and related tubal rupture?

PURPOSE

The present study aims to determine whether sonographic endometrial pattern can be addressed as an early indicator for tubal ectopic pregnancy and related tubal rupture in case ultrasonography reveals no adnexal mass and maternal serum beta human chorionic gonadotropin (HCG) level is below the discriminatory zone (<or=1,000 mIU/mL).

METHODS

The study evaluated the endometrial features of 441 naturally conceived and asymptomatic first trimester (99 tubal ectopic, 138 failing and 264 normal intrauterine) with maternal serum beta HCG levels<or=1,000 mIU/mL and indeterminate sonographic findings.

RESULTS

Tubal ectopic, failing intrauterine and normal intrauterine pregnancies are statistically similar in aspect of endometrial thickness. However, trilaminar endometrial pattern was significantly less frequent in failing and normal intrauterine pregnancies but significantly more frequent in ruptured tubal pregnancies. Also the relative risk of tubal rupture is significantly higher in case of trilaminar endometrial pattern. Trilaminar endometrial pattern has a sensitivity of 21.2%, specificity of 93.9%, positive predictive value of 50.0% and negative predictive value of 80.5% for distinguishing tubal ectopic pregnancy. Moreover, the sensitivity, specificity, positive and negative predictive values of the same pattern are computed to be 60.0, 95.7, 85.7 and 84.6%, respectively, in the prediction of ruptured tubal pregnancy.

CONCLUSIONS

Sonographic appearance of endometrium may be used to predict tubal pregnancy when ultrasonography shows no adnexal mass and maternal serum HCG<or=1,000 mIU/mL. That is, trilaminar pattern may indicate tubal pregnancy and warn about a possible related rupture in case of previous ectopic pregnancy or pelvic surgery.

Endometrial thickness predicts intrauterine pregnancy in patients with pregnancy of unknown location

OBJECTIVE

To determine whether endometrial thickness and other parameters are useful predictors of normal intrauterine pregnancy (IUP) in the setting of vaginal bleeding and sonographic diagnosis of pregnancy of unknown location (PUL).

METHODS

We reviewed the clinical and sonographic records of all 591 patients with vaginal bleeding and a sonographic diagnosis of PUL between 1 July 2005 and 30 June 2006. Data on maternal age, gravidity, parity, estimated gestational age by last menstrual period (EGA by LMP), endometrial thickness and serum beta-human chorionic gonadotropin (beta-hCG) were collected. Complete data were available for 517 patients, 40 (7.7%) of whom ultimately had normal IUPs. A logistic regression model was constructed using a stepwise procedure to identify variables significantly associated with the outcome of normal IUP. The validity of the model was assessed by receiver-operating characteristics (ROC) curve and Hosmer-Lemeshow Chi-square analysis.

RESULTS

Four variables (maternal age, EGA by LMP, endometrial thickness and serum beta-hCG) were significant in the prediction of normal IUP (area under the ROC curve = 0.86). As maternal age, EGA by LMP and beta-hCG increased, the likelihood of a normal IUP decreased, while as the endometrial thickness increased, the likelihood of a normal IUP increased. For each millimeter increase in endometrial thickness, the odds increased by 27% that the patient would have a normal IUP. No normal IUP had an endometrial thickness < 8 mm.

CONCLUSION

Increased endometrial thickness predicts normal IUP in patients who present with vaginal bleeding and PUL.

Role of sonography in the diagnosis of ectopic pregnancy

This review addresses the use of sonography in the evaluation of patients suspected of having ectopic pregnancy. The use of transvaginal and transabdominal sonography and the role of Doppler imaging in the early diagnosis of ectopic pregnancy are discussed. Various sonographic findings and pitfalls of ectopic pregnancy are analyzed, with emphasis on their diagnostic efficacies.

Sonographic Evaluation of Ectopic Pregnancy

Ectopic pregnancy is a high-risk condition that occurs in 1.9% of reported pregnancies. Although the clinical triad of pain, bleeding, and amenorrhea is considered very specific for an ectopic pregnancy, ultrasound plays important role in detecting the exact location of the ectopic pregnancy and also in providing guidance for minimally invasive treatment. This article discusses the main sonographic features of ectopic pregnancy at various common and unusual locations. In addition, it provides insight into the role of hormonal markers in the diagnosis and management of ectopic pregnancy.

Ultrasonographic endometrial features in tubal pregnancy: are they predictive factors of successful medical treatment?

The aim of this study was to explain possible relationships in cases of ectopic pregnancy between sonographic endometrial features and treatment outcome following methotrexate (MTX) injection. A total of 157 cases of unruptured tubal pregnancy were diagnosed and treated systemically with MTX. The sonographic endometrial pattern, endometrial thickness and treatment outcome were retrospectively analyzed. There were four types of endometrial patterns: these were trilaminar, homogeneous, heterogeneous and pseudosac. Success rates following MTX treatment were different for each group: these were 64.7%, 78.4%, 50.0% and 46.2%, respectively (p = 0.0129). And the risk of treatment failure was increased 3.64 times (95% CI 1.56 to 8.49) in heterogeneous thick pattern and 4.24 times (95% CI 1.18 to 15.23) in pseudosac pattern. In conclusion, when tubal pregnancy was seen in a pseudogestational sac pattern or a heterogeneous pattern, the failure rate of medical treatment was increased. This can serve as a reference for considering the decision about medical treatment in women with unruptured tubal pregnancy.

The nonsurgical management of ectopic pregnancy

PURPOSE OF REVIEW

This review discusses the diagnosis and nonsurgical management of ectopic pregnancy.

RECENT FINDINGS

In the majority of cases the diagnosis of ectopic pregnancy should be made on transvaginal ultrasonography. Those for which the diagnosis is not made on the first scan may initially be classified as pregnancies of unknown location. There are now a number of strategies and mathematical models to predict ectopic pregnancy in this pregnancy of unknown location population. Reported success rates for expectant and medical management of ectopic pregnancy vary due to different inclusion criteria. A number of predictors of success have been studied: maternal age, previous obstetric history, gestational age, ultrasound features, human chorionic gonadotrophin levels, progesterone levels and the change in human chorionic gonadotrophin over time. At present the initial human chorionic gonadotrophin level probably remains the single most important predictor of success. Nonsurgical management is also particularly important for nontubal ectopic pregnancies: interstitial, cervical and caesarean section scar pregnancies.

SUMMARY

The majority of ectopic pregnancies can be visualized by ultrasound and so can be considered for conservative treatment. Nonsurgical management can be safe and effective. Appropriate selection criteria remain an issue, however, and a consensus needs to be reached on the predictors of success and failure to optimize management.