There is no role for uterine curettage in the contemporary diagnostic workup of women with a pregnancy of unknown location

Safety of methotrexate administration in women with pregnancy of unknown location at high risk of ectopic pregnancy

OBJECTIVES

To evaluate the safety of current guidelines on methotrexate (MTX) administration in women with pregnancy of unknown location (PUL) who are considered to have a high risk of underlying ectopic pregnancy (EP), and to investigate whether implementation of these guidelines would result in inadvertent exposure to MTX of viable intrauterine pregnancies (IUPs).

METHODS

This was a retrospective observational study of consecutive clinically stable women who were classified with PUL at the early pregnancy unit of Nepean Hospital, Sydney, Australia, between 2007 and 2021. PUL was defined as a positive pregnancy test in the absence of signs of IUP or EP on transvaginal ultrasound. Patients with a PUL that behaved biochemically like an EP, but for which the location of pregnancy was not confirmed on ultrasound, were eligible for MTX to minimize the risk of subsequent tubal rupture. Criteria discussed in the guidelines of the American College of Obstetricians and Gynecologists (ACOG), American Society for Reproductive Medicine (ASRM), Royal College of Obstetricians and Gynaecologists (RCOG) and National Institute for Health and Care Excellence (NICE) were applied to the PUL database. The number of patients eligible to receive MTX and the number with an underlying viable IUP who would be inadvertently prescribed MTX were calculated.

RESULTS

A total of 816 women with PUL were reviewed, of whom 724 had complete data and were included in the final analysis. Six patients had persistent PUL and the remaining 718 had a diagnosis of viable IUP, non-viable IUP, EP or failed PUL. According to the ACOG, ASRM, RCOG and NICE guidelines, the rate of MTX administration among patients with PUL would have been 2.76%, 4.56%, 0.41% and 35.36%, respectively. However, no persistent PUL would have received MTX according to the ACOG, ASRM and RCOG protocols (the NICE protocol identified patients with persistent PUL with a sensitivity of 100%), and the majority of MTX treatments were unnecessary because those patients were later classified as having non-viable IUP or failed PUL. Application of ACOG and ASRM guidance could result theoretically in inadvertent MTX administration to women with an underlying viable IUP at a rate of 4.1/1000 (3/724).

CONCLUSIONS

Current guidelines used to predict high risk of EP in the PUL population lead to inadvertent MTX administration to women with an underlying viable IUP. These guidelines should be used wisely to ensure that no wanted pregnancy is exposed to MTX. Women with PUL should be monitored carefully, and MTX should be used judiciously when the location of pregnancy is yet to be confirmed. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

β-Human Chorionic Gonadotropin Dynamics in Early Gestational Events: A Practical and Updated Reappraisal

In the last decade, the widespread use of transvaginal ultrasound and the availability of highly specific serum assays of human chorionic gonadotropin (hCG) have become mainstays in the evaluation of early pregnancy. These tests have revolutionized the management of pregnancies of unknown location and markedly reduced the morbidity and mortality associated with the misdiagnosis of ectopic pregnancy. However, despite several advances, their misuse and misinterpretations are still common, leading to an increased use of healthcare resources, patient misinformation, and anxiety. This narrative review aims to succinctly summarize the β-hCG dynamics in early gestation and provide general gynecologists a practical approach to patients with first-trimester symptomatic pregnancy.

The Utility of Monitoring Beta-Human Chorionic Gonadotropin Levels in an Ectopic Pregnancy

Ectopic pregnancy, a rare complication involving embryo nidation outside the uterus, significantly impacts women's lives worldwide. About 95% of ectopic pregnancies occur in the Fallopian tubes. If not diagnosed early, the patient may suffer from tubal rupture, resulting in hemorrhage and lethal consequences. Transvaginal ultrasound (TVUS) is typically used to diagnose an ectopic pregnancy. However, over the last decade, monitoring beta-human chorionic gonadotropin (β-hCG) levels in ectopic pregnancy have evolved to detect ectopic pregnancy. But there are inconsistencies in its utility in monitoring or diagnosing ectopic pregnancy in clinical practice. This systematic review highlights the potential of monitoring β-hCG levels to accurately diagnose ectopic pregnancy. Furthermore, it showcases if β-hCG levels can determine effective treatment options to successfully resolve an ectopic pregnancy. We performed a literature search between January 2022 through December 2022 following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The clinical evidence demonstrated that monitoring β-hCG levels, combined with TVUS, accurately diagnosed an ectopic pregnancy. Moreover, pre-treatment β-hCG levels higher than 5000 international units per liter (IU/L), statistically significant, indicated surgical management for a successful resolution of an ectopic pregnancy. Whereas lower β-hCG levels showed successful management through expectant and methotrexate treatment. Interestingly, patients who failed non-surgical treatment developed increased β-hCG levels and required surgical intervention. However, there was conflicting evidence on whether β-hCG levels could indicate tubal rupture. Nevertheless, as highlighted in this review, monitoring β-hCG levels could be crucial in the early diagnosis of ectopic pregnancy. Besides, it might significantly aid in monitoring and deciding on effective treatment options for patients with ectopic pregnancy, which could be vital to saving their lives and preserving fertility.

Pregnancy of unknown location

Pregnancy of unknown location is a situation in which a positive pregnancy test occurs, but a transvaginal ultrasound does not show intrauterine or ectopic gestation. One great concern of pregnancy of unknown location is that they are cases of ectopic pregnancy whose diagnosis might be postponed. Transvaginal ultrasound is able to identify an ectopic pregnancy with a sensitivity ranging from 87% to 94% and a specificity ranging from 94% to 99%. A patient with pregnancy of unknown location should be followed up until an outcome is obtained. The only valid biomarkers with clinical application and validation are serum levels of the beta fraction of hCG and progesterone. A single serum dosage of hCG is used only to determine whether the value obtained is above or below the discriminatory zone, that means the value of serum hCG above which an intrauterine gestational sac should be visible on ultrasound. Serum progesterone levels are a satisfactory marker of pregnancy viability, but they are unable to predict the location of a pregnancy of unknown location: levels below 5 ng/mL are associated with nonviable gestations, whereas levels above 20 ng/mL are correlated with viable intrauterine pregnancies. Most cases are low risk and can be monitored by expectant management with transvaginal ultrasound and serial serum hCG levels, in addition to the serum progesterone levels. To minimize diagnostic error and intervene during progressive intrauterine gestation, protocol indicates active treatment only in situations when progressive intrauterine pregnancy is excluded and a high possibility of ectopic pregnancy exists.

Trends in the Management of Nonviable Pregnancies of Unknown Location in the United States

BACKGROUND

When managing a nonviable pregnancy of unknown location (PUL), a debate has emerged in the literature whether to perform uterine curettage for definitive diagnosis of pregnancy location or administer methotrexate for a presumed ectopic pregnancy. The purpose of this study is to describe the treatment patterns when managing a PUL.

METHODS

A prospective, anonymous Internet based-electronic survey of PUL case scenarios was administered to a random sample of physicians across the United States.

RESULTS

A total of 214 physicians responded. When presented with a PUL by ultrasound and a βhCG measurement of 3,270 mIU/mL, which is above the discriminatory level, 88.3% (188) would choose an additional βhCG measurement before recommending any intervention. When presented with a PUL by ultrasound and serial βhCG measurements demonstrating an inappropriate trend for a viable gestation, 36.5% would offer uterine curettage and 31.3% would offer methotrexate. Resident and private clinicians had a fourfold lower adjusted odds of choosing uterine curettage compared to academic physicians.

CONCLUSIONS

Based on our findings, there does not appear to be a consensus regarding the management of a PUL.

Morphological ultrasound types known as 'blob' and 'bagel' signs should be reclassified from suggesting probable to indicating definite tubal ectopic pregnancy

OBJECTIVE

In a recent consensus statement on early pregnancy nomenclature by Barnhart, a definite ectopic pregnancy (EP) was defined morphologically on transvaginal sonography (TVS) as an extrauterine gestational sac with yolk sac and/or embryo, with or without cardiac activity, whilst a probable EP was defined as an inhomogeneous adnexal mass ('blob' sign) or extrauterine sac-like structure ('bagel' sign). This study aims to determine whether these ultrasound markers used to define probable EP can be used to predict a definite tubal EP.

METHODS

This was a retrospective cohort study of women presenting to the Early Pregnancy Unit (EPU) at Nepean Hospital, Sydney, Australia between November 2006 and June 2016. Women classified with a probable EP or a pregnancy of unknown location (PUL), i.e. with no signs of extra- or intrauterine pregnancy (IUP), at their first TVS were included, whilst those with a definite tubal EP, IUP or non-tubal EP were excluded from the final analysis. The gold standard for tubal EP was histological confirmation of chorionic villi in Fallopian tube removed at laparoscopy. The performance of blob or bagel sign on TVS in the prediction of definite tubal EP was evaluated in terms of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). This was compared with the performance of extrauterine gestational sac with yolk sac and/or embryo on TVS to predict definite tubal EP.

RESULTS

During the study period, 7490 consecutive women attended the EPU, of whom 849 were analyzed. At primary TVS, 240/849 were diagnosed with probable EP, of which 174 (72.5%) were classified as blob sign and 66 (27.5%) as bagel sign. The remaining 609/849 were diagnosed with PUL, of which 47 had a final diagnosis of EP (including 24 blob sign, 19 bagel sign and four gestational sac with embryo/yolk sac). 101 of all 198 (51%) blob sign cases and 50 of all 85 (59%) bagel sign cases underwent laparoscopy and salpingectomy; histology proved a tubal EP in 98 (97%) of these blob-sign cases and 48 (96.0%) of the bagel-sign cases. The sensitivity for the blob and bagel signs in the prediction of definite tubal EP was 89.8% and 83.3%, respectively, the specificity was 99.5% and 99.6%, PPV was 96.7% and 95.2% and NPV was 98.3% and 98.6%. This was comparable to the sensitivity of extrauterine gestational sac with yolk sac and/or embryo on TVS in the prediction of definite tubal EP (sensitivity, 84.0%; specificity, 99.9%; PPV, 97.7%; NPV, 99.3% (P = 0.5)).

CONCLUSIONS

Blob and bagel signs seem to be the most common presentations of a tubal EP on TVS. Although they cannot be considered as a definitive sign of EP, their PPV is very high (> 95%); such women should therefore be considered at very high risk for having a tubal EP and should be treated as such. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Is there a difference in the behaviour and subsequent management of ectopic pregnancies seen at first scan compared to those ectopic pregnancies which commence as pregnancies of unknown location?

AIMS

The primary aim was to assess whether ectopic pregnancies (EPs) visualised on primary scan behave differently to EPs initially characterised as pregnancies of unknown location (PUL). The secondary aim was to assess whether the EP group is more likely to have surgical management compared to the PUL ectopic pregnancy group.

MATERIALS AND METHODS

Prospective observational study. Consecutive first trimester women presenting from November 2006 to March 2012 underwent transvaginal ultrasound (TVS). Women diagnosed with an EP on TVS were divided into two groups: visualised EPs noted on the first TVS, and PULs which subsequently developed into EPs. Twenty-five historical, clinical, biochemical and ultrasonographic variables were collected. Different management strategies (expectant, medical, surgical) once an EP was confirmed on TVS were recorded. Univariate analysis was performed to compare differences between the two groups as well as rates for the three final management strategies.

RESULTS

A total of 3341 consecutive women underwent TVS. On initial scan, 86.2% were classified as intrauterine pregnancy, 8.8% as PUL and 5.0% as EP (145 tubal/23 nontubal EPs). There were 194 tubal EPs in final analysis: 49 of 194 (25.3%) initially classified as PUL and 145 of 194 (74.7%) diagnosed as EP at primary TVS. When comparing the EP to the PUL EP group, the pain scores were 3.34 versus 1.91 (P-value < 0.001), the mean sac diameters were 35.2 versus 18.5 mm (P-value = 0.0327), and the volume of the EP masses were 8.21E+04 versus 1.40E+04 (P-value = 0.0341). Cumulative surgical intervention rate was significantly higher in EP compared to PUL EP group (P-value = 0.036).

CONCLUSIONS

EPs seen at the first ultrasound scan appear to be more symptomatic, larger in diameter and volume compared to EPs which started as PULs. Cumulative surgical intervention rate was noted to be higher in this group with EP seen on ultrasound at the outset.

A pragmatic and evidence-based management of ectopic pregnancy

The incidence of ectopic pregnancy is approximately 2% of all pregnancies, and it remains the leading cause of death in early pregnancy. Over 95% of ectopic pregnancies are tubal pregnancies, and the remainders are nontubal pregnancies. The highest risk factor for ectopic pregnancy is a previous tubal pregnancy followed by previous tubal surgery, tubal sterilization, tubal pathology, and current intrauterine device use. The apparent increase in the incidence of nontubal ectopic pregnancy including heterotopic pregnancy may be attributed to the increasing number of pregnancies because of in vitro fertilization treatment. In most cases, an ectopic pregnancy can be treated medically with a single dose of methotrexate. Surgical treatment is still needed in women who are hemodynamically unstable and in those who do not fulfill the criteria for methotrexate treatment. Usually surgical treatment can be performed by laparoscopy and in some cases by hysteroscopy. Laparotomy is rarely needed even in women with intraperitoneal bleeding.

Is there a need to definitively diagnose the location of a pregnancy of unknown location? The case for "no"

The ability to predict the outcome of a pregnancy of unknown location (PUL) has been extensively studied over the past decade. Between 8%-14% of PULs will develop into ectopic pregnancies (EP), and therefore the need to confirm pregnancy location is not without good reason. Strategies to predict EP in the PUL population have included the use of various maternal serum biomarkers and repeat transvaginal ultrasound (TVS) examinations in order to avoid delaying this diagnosis. These follow-up tests are associated with substantial financial cost to the healthcare system, as well as impacting on maternal anxiety. However, the majority of women with a PUL at follow-up will either have an intra-uterine pregnancy or a spontaneously resolving PUL, and therefore represent low-risk PULs. Most of these low-risk PULs do not need intervention and expectant management has been shown to be safe and not associated with adverse outcomes. Therefore we need consider whether the current strategies to determine pregnancy location are indeed essential for women with a PUL, especially when balancing the additional health care burden with the potential increase in maternal morbidity/mortality associated with delay in diagnosis. This beckons the question, "Do we really need to definitively diagnose pregnancy location in women with a PUL?

When is a pregnancy nonviable and what criteria should be used to define miscarriage?

In 2011, the first systematic review of the evidence behind the diagnostic criteria for miscarriage was published. It states, "findings were limited by the small number and poor quality of the studies," and concluded that further studies were, "urgently required before setting future standards for the accurate diagnosis of early embryonic demise." This implies that data used to define criteria to diagnose miscarriage are unreliable. The 2011 Irish Health Service executive review into miscarriage misdiagnosis highlighted this issue. In parallel to these publications a multicenter prospective study was published examining cut-off values for mean sac diameter (MSD) and embryo size to define miscarriage. The authors also published evidence on expected findings when ultrasonography is repeated at an interval. This led to guidance on diagnostic criteria for miscarriage in the UK changing. These new criteria state miscarriage be considered only when: an empty gestation sac has an MSD of ≥ 25 mm (with no obvious yolk sac), or embryonic crown rump length ≥ 7 mm (the latter without evidence of fetal heart activity). If in doubt, repeating scans at an interval is emphasized. It is axiomatic that decisions about embryonic viability must not be open to doubt. So it is surprising how little evidence exists to support previous guidance. Any clinician working in this area knows of women being wrongly informed that their pregnancy has failed. This cannot be acceptable and guidance in this area must be "failsafe."

The term "pregnancy of unknown location" is here to stay

The term "pregnancy of unknown location" is an ultrasound classification and not a final diagnosis. The use of this terminology is here to stay and should continue as long as there is an appreciation for what it really means. It is the responsibility of the clinician, who follows up these women with a PUL, to ensure that a final diagnosis is achieved while preserving the well-being of these women.

Ultrasound diagnosis of ectopic pregnancy

Ectopic pregnancy (EP) remains the number one cause of first trimester maternal death. Traditionally, laparoscopy has been the gold standard for diagnosis of EP. The advent of high-resolution transvaginal scan (TVS) means more clinically stable women with EPs are diagnosed earlier, well before surgery becomes necessary in many cases. Early diagnosis by TVS is therefore potentially life saving and can reduce surgical morbidity by allowing elective surgery or even non-surgical conservative treatment options. Combining transabdominal and transvaginal scanning confers no benefit over transvaginal scanning alone. Reports that reads "…empty uterus, ectopic pregnancy cannot be excluded" should be a thing of the past. Diagnosis of EP should be based upon the positive identification of an adnexal mass using TVS rather than the absence of an intra-uterine gestational sac. A systematic approach to scanning the early pregnancy pelvis will diagnose the vast majority of EPs at the initial scan. Ultrasound, and in particular TVS, is fast becoming the new gold standard for diagnosis of all types of EP. In modern management, laparoscopy should be seen as the operative tool of choice while TVS the diagnostic tool of choice.

Pregnancy of unknown location: a consensus statement of nomenclature, definitions, and outcome

OBJECTIVE

To improve the interpretation of future studies in women who are initially diagnosed with a pregnancy of unknown location (PUL), we propose a consensus statement with definitions of population, target disease, and final outcome.

DESIGN

A review of literature and a series of collaborative international meetings were used to develop a consensus for definitions and final outcomes of women initially diagnosed with a PUL.

RESULT(S)

Global differences were noted in populations studied and in the definitions of outcomes. We propose to define initial ultrasound classification of findings into five categories: definite ectopic pregnancy (EP), probable EP, PUL, probable intrauterine pregnancy (IUP), and definite IUP. Patients with a PUL should be followed and final outcomes should be categorized as visualized EP, visualized IUP, spontaneously resolved PUL, and persisting PUL. Those with the transient condition of a persisting PUL should ultimately be classified as nonvisualized EP, treated persistent PUL, resolved persistent PUL, or histologic IUP. These specific categories can be used to characterize the natural history or location (intrauterine vs. extrauterine) of any early gestation where the initial location is unknown.

CONCLUSION(S)

Careful definition of populations and classification of outcomes should optimize objective interpretation of research, allow objective assessment of future reproductive prognosis, and hopefully lead to improved clinical care of women initially identified to have a PUL.

Does a prediction model for pregnancy of unknown location developed in the UK validate on a US population?

BACKGROUND

A logistic regression model (M4) was developed in the UK to predict the outcome for women with a pregnancy of unknown location (PUL) based on the initial two human chorionic gonadotrophin (hCG) values, 48 h apart. The purpose of this paper was to assess the utility of this model to predict the outcome for a woman (PUL) in a US population.

METHODS

Diagnostic variables included log-transformed serum hCG average of two measurements, and linear and quadratic hCG ratios. Outcomes modeled were failing PUL, intrauterine pregnancy (IUP) and ectopic pregnancy (EP). This model was applied to a US cohort of 604 women presenting with symptomatic first-trimester pregnancies, who were followed until a definitive diagnosis was made. The model was applied before and after correcting for differences in terminology and diagnostic criteria.

RESULTS

When retrospectively applied to the adjusted US population, the M4 model demonstrated lower areas under the curve compared with the UK population, 0.898 versus 0.988 for failing PUL/spontaneous miscarriage, 0.915 versus 0.981 for IUP and 0.831 versus 0.904 for EP. Whereas the model had 80% sensitivity for EP using UK data, this decreased to 49% for the US data, with similar specificities. Performance only improved slightly (55% sensitivity) when the US population was adjusted to better match the UK diagnostic criteria.

CONCLUSIONS

A logistic regression model based on two hCG values performed with modest decreases in predictive ability in a US cohort for women at risk for EP compared with the original UK population. However, the sensitivity for EP was too low for the model to be used in clinical practice in its present form. Our data illustrate the difficulties of applying algorithms from one center to another, where the definitions of pathology may differ.

Predicting Outcomes in Pregnancies of Unknown Location

A pregnancy of unknown location (PUL) is a descriptive term used to classify a woman when she has a positive pregnancy test but no intra- or extra-uterine pregnancy is visualized on transvaginal sonography. Expectant management has been shown to be safe for the majority of women with a PUL. Serum progesterone and human chorionic gonadotrophin levels as well as mathematical models play a role in predicting the final outcomes of PULs, which include intrauterine pregnancy, failing PUL and ectopic pregnancy. Other possible predictors of outcome have been studied, but currently no factor has been identified that combines accuracy with reproducibility and simplicity. This article discusses the various aspects of the management of women with PULs. Future work should be aimed at prospectively testing current models in order to predict the outcome of a PUL and minimizing follow-up.

Prediction of ectopic pregnancy in women with a pregnancy of unknown location

OBJECTIVE

We have previously published on the use of mathematical Model M1 to predict ectopic pregnancy in women with no signs of intra- or extrauterine pregnancy. The aim of this study was to improve on the performance of this model for the detection of developing ectopic pregnancies in women with pregnancies of unknown location (PULs). We therefore generated and evaluated a new logistic regression model from simple hormonal data and compared it with Model M1.

METHODS

Data were collected prospectively from women classified as having a PUL. These women were followed until the diagnosis was established as: a failing PUL, an intrauterine pregnancy (IUP) or an ectopic pregnancy. A multinomial logistic regression model, Model M4, was developed on 201 training cases and it was tested prospectively on another 175 women with a PUL. M4 performance was evaluated using receiver-operating characteristics (ROC) curves and compared with Model M1 based on the human chorionic gonadotropin (hCG) ratio alone.

RESULTS

A total of 376 women with a PUL were recruited into this study: 201 in the training set (109 (54.2%) with a failing PUL, 76 (37.8%) with an IUP and 12 (6.0%) with an ectopic pregnancy; four with a persisting PUL were excluded from analysis) and 175 in the test set (94 (53.7%) with a failing PUL, 64 (36.6%) with an IUP and 15 (8.6%) with an ectopic pregnancy; two with a persisting PUL were excluded from analysis). The log serum hCG average ((hCG 0 h + hCG 48 h)/2) and the hCG ratio (hCG 48 h/hCG 0 h) were encoded as variables following multivariate analysis of the basic data. The new Model M4 contained the log of the hCG average, the hCG ratio and its quadratic effect. In the prediction of ectopic pregnancy, M4 gave an area under the ROC curve (AUC) of 0.900 and M1 gave an AUC of 0.842 (P = 0.0303).

CONCLUSIONS

Although Model M4 is superior to Model M1 when comparing the AUCs for prediction of developing ectopic pregnancies in a PUL population, in real terms this model did not result in substantially more pregnancies being classified correctly as developing ectopic pregnancies. Prospective multicenter studies are needed to assess the diagnostic performance of such models in different populations.