A prospective evaluation of a single-visit strategy to manage pregnancies of unknown location

Cost-effectiveness analysis of expectant vs active management for treatment of persistent pregnancies of unknown location

BACKGROUND

Persistent pregnancies of unknown location are defined by abnormally trending serum human chorionic gonadotropin with nondiagnostic ultrasound. There is no consensus on optimal management.

OBJECTIVE

This study aimed to assess the cost-effectiveness of 3 primary management strategies for persistent pregnancies of unknown location: (1) expectant management, (2) empirical 2-dose methotrexate, and (3) uterine evacuation followed by methotrexate, if indicated.

STUDY DESIGN

This was a prospective economic evaluation performed concurrently with the Expectant versus Active Management for Treatment of Persistent Pregnancies of Unknown Location multicenter randomized trial that was conducted from July 2014 to June 2019. Participants were randomized 1:1:1 to expectant management, 2-dose methotrexate, or uterine evacuation. The analysis was from the healthcare sector perspective with a 6-week time horizon after randomization. Costs were expressed in 2018 US dollars. Effectiveness was measured in quality-adjusted life years and the rate of salpingectomy. Incremental cost-effectiveness ratios and cost-effectiveness acceptability curves were generated. Sensitivity analyses were performed to assess the robustness of the analysis.

RESULTS

Methotrexate had the lowest mean cost ($875), followed by expectant management ($1085) and uterine evacuation ($1902) (P=.001). Expectant management had the highest mean quality-adjusted life years (0.1043), followed by methotrexate (0.1031) and uterine evacuation (0.0992) (P=.0001). The salpingectomy rate was higher for expectant management than for methotrexate (9.4% vs 1.2%, respectively; P=.02) and for expectant management than for uterine evacuation (9.4% vs 8.1%, respectively; P=.04). Uterine evacuation, with the highest costs and the lowest quality-adjusted life years, was dominated by both expectant management and methotrexate. In the base case analysis, expectant management was not cost-effective compared with methotrexate at a willingness to pay of $150,000 per quality-adjusted life year given an incremental cost-effectiveness ratio of $175,083 per quality-adjusted life year gained (95% confidence interval, -$1,666,825 to $2,676,375). Threshold analysis demonstrated that methotrexate administration would have to cost $214 (an increase of $16 or 8%) to favor expectant management. Moreover, expectant management would be favorable in lower-risk patient populations with rates of laparoscopic surgical management for ectopic pregnancy not exceeding 4% of pregnancies of unknown location. Based on the cost-effectiveness acceptability curves, the probability of expectant management being cost-effective compared with methotrexate at a willingness to pay of $150,000 per quality-adjusted life year gained was 50%. The results were dependent on the cost of surgical intervention and the expected rate of methotrexate failure.

CONCLUSION

The management of pregnancies of unknown location with a 2-dose methotrexate protocol may be cost-effective compared with expectant management and uterine evacuation. Although uterine evacuation was dominated, expectant management vs methotrexate results were sensitive to modest changes in treatment costs of both methotrexate and surgical management.

Diagnostic value of a urine test in pregnancy of unknown location

BACKGRO

Pregnancy of unknown location (PUL) is a term used when there is a positive pregnancy test but no sonographic evidence for an intrauterine pregnancy (IUP) or ectopic pregnancy (EP). This term is a classification and not a final diagnosis.

OBJECTIVE

This study aimed to evaluate the diagnostic value of the Inexscreen test on the outcome of patients with pregnancies of unknown location.

STUDY DESIGN

In this prospective study, a total of 251 patients with a diagnosis of pregnancy of unknown location at the gynecologic emergency department of the La Conception Hospital, Marseille, France, between June 2015 and February 2019 were included. The Inexscreen (semiquantitative determination of intact human urinary chorionic gonadotropin) test was performed on patients with a diagnosis of pregnancy of unknown location. They participated in the study after information and consent collection. The main outcome measures (sensitivity, specificity, predictive values, and the Youden index) of Inexscreen were calculated for the diagnosis of abnormal pregnancy (nonprogressive pregnancy) and ectopic pregnancy.

RESULTS

The sensitivity and specificity of Inexscreen for the diagnosis of abnormal pregnancy in patients with pregnancy of unknown location were 56.3% (95% confidence interval, 47.0%-65.1%) and 62.8% (95% confidence interval, 53.1%-71.5%), respectively. The sensitivity and specificity of Inexscreen for the diagnosis of ectopic pregnancy in patients with pregnancy of unknown location were 81.3% (95% confidence interval, 57.0%-93.4%) and 55.6% (95% confidence interval, 48.6%-62.3%), respectively. The positive predictive value and negative predictive value of Inexscreen for ectopic pregnancy were 12.9% (95% confidence interval, 7.7%-20.8%) and 97.4% (95% confidence interval, 92.5%-99.1%), respectively.

CONCLUSION

Inexscreen is a rapid, non-operator-dependent, noninvasive, and inexpensive test that allows the selection of patients at high risk of ectopic pregnancy in case of pregnancy of unknown location. This test allows an adapted follow-up according to the technical platform available in a gynecologic emergency service.

[Retrospective validation of a model to predict the outcome of pregnancies of unknown location]

OBJECTIVE

The prediction model M6 classifies pregnancy of unknown location (PUL) into a low-risk or a high-risk group in developing ectopic pregnancy (EP). The aim of this study was to validate the two-step M6 model's ability to classify PUL in French women.

MATERIAL AND METHODS

All women with a diagnosis of PUL over a year were included in this single center retrospective study. Patients with a diagnosis of EP at the first consultation of with incomplete data were excluded. For each patient, the M6 model calculator was used to classified them into "high risk of EP" and "low risk of EP" group. The reference standard was the final diagnostic: failed PUL (FPUL), intrauterine pregnancy (IUP) of EP. The statistical measures of the test's performance were calculated.

RESULTS

Over the period, 255 women's consulted for a PUL, 197 has been included in the study. Final diagnosis were: 94 FPUL (94/197; 47.7%), 74 IUP (74/197; 37.6%) et 29 EP (29/197; 14.7%). The first step of the M6 model classified 16 women in the FPUL group of which 15 (15/16; 93.7%) correctly. The second step of the M6 model classified 181 women: 90 (90/181; 49.7%) in the "high risk of EP" group of which 63 (63/90; 70%) were FPUL/IUP and 27 (27/90; 30%) were EP. 91 (91/181; 50.3%) was classified in the "low risk of EP" group of which 90 (90/91; 98.9%) were FPUL/IUP and 1 (1/91; 1.1%) were EP. EP were correctly classified with sensitivity of 96.4%, negative predictive value of 98.9%, specificity of 58.8% and positive predictive value of 30.0%.

CONCLUSIONS

The prediction model of PUL M6 classified EP in "high risk of EP group" with a sensitivity of 96.4%. It classified 50.3% of PUL in a "low risk of EP" group with a negative predictive value of 98.9%.

Triaging women with pregnancy of unknown location using two-step protocol including M6 model: clinical implementation study

OBJECTIVE

The M6 risk-prediction model was published as part of a two-step protocol using an initial progesterone level of ≤ 2 nmol/L to identify probable failing pregnancies (Step 1) followed by the M6 model (Step 2). The M6 model has been shown to have good triage performance for stratifying women with a pregnancy of unknown location (PUL) as being at low or high risk of harboring an ectopic pregnancy (EP). This study validated the triage performance of the two-step protocol in clinical practice by evaluating the number of protocol-related adverse events and how effectively patients were triaged.

METHODS

This was a prospective multicenter interventional study of 3272 women with a PUL, carried out between January 2015 and January 2017 in four district general hospitals and four university teaching hospitals in the UK. The final pregnancy outcome was defined as: a failed PUL (FPUL), an intrauterine pregnancy (IUP) or an EP (including persistent PUL (PPUL)). FPUL and IUP were grouped as low-risk and EP/PPUL as high-risk PUL. Serum progesterone and human chorionic gonadotropin (hCG) levels were measured at presentation in all patients. If the initial progesterone level was ≤ 2 nmol/L, patients were discharged and were asked to have a follow-up urine pregnancy test in 2 weeks to confirm a negative result. If the progesterone level was > 2 nmol/L or a measurement had not been taken, hCG level was measured again at 48 h and results were entered into the M6 model. Patients were managed according to the outcome predicted by the protocol. Those classified as 'low risk, probable FPUL' were advised to perform a urine pregnancy test in 2 weeks and those classified as 'low risk, probable IUP' were invited for a scan a week later. When a woman with a PUL was classified as high risk (i.e. risk of EP ≥ 5%) she was reviewed clinically within 48 h. One center used a progesterone cut-off of ≤ 10 nmol/L and its data were analyzed separately. If the recommended management protocol was not adhered to, this was recorded as a protocol deviation and classified as: unscheduled visit for clinician reason, unscheduled visit for patient reason or incorrect timing of blood test or ultrasound scan. The classifications outlined in the UK Good Clinical Practice (GCP) guidelines were used to evaluate the incidence of adverse events. Data were analyzed using descriptive statistics.

RESULTS

Of the 3272 women with a PUL, 2625 were included in the final analysis (317 met the exclusion criteria or were lost to follow-up, while 330 were evaluated using a progesterone cut-off of ≤ 10 nmol/L). Initial progesterone results were available for 2392 (91.1%) patients. In Step 1, 407 (15.5%) patients were classified as low risk (progesterone ≤ 2 nmol/L), of whom seven (1.7%) were ultimately diagnosed with an EP. In 279 of the remaining 2218 women with a PUL, the M6 model was not applied owing to protocol deviation or because the outcome was already known (usually on the basis of an ultrasound scan) before a second hCG reading was taken; of these patients, 30 were diagnosed with an EP. In Step 2, 1038 women with a PUL were classified as low risk, of whom eight (0.8%) had a final outcome of EP. Of 901 women classified as high risk at Step 2, 275 (30.5%) had an EP. Therefore, 275/320 (85.9%) EPs were correctly classified as high risk. Overall, 1445/2625 PUL (55.0%) were classified as low risk, of which 15 (1.0%) were EP. None of these cases resulted in a ruptured EP or significant clinical harm. Sixty-two women participating in the study had an adverse event, but no woman had a serious adverse event as defined in the UK GCP guidelines.

CONCLUSIONS

This study has shown that the two-step protocol incorporating the M6 model effectively triaged the majority of women with a PUL as being at low risk of an EP, minimizing the follow-up required for these patients after just two visits. There were few misclassified EPs and none of these women came to significant clinical harm or suffered a serious adverse clinical event. The two-step protocol incorporating the M6 model is an effective and clinically safe way of rationalizing the management of women with a PUL. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Diagnostic protocols for the management of pregnancy of unknown location: a systematic review and meta-analysis

BACKGROUND

There is no international consensus on how to manage women with a pregnancy of unknown location (PUL).

OBJECTIVES

To present a systematic quantitative review summarising the evidence related to management protocols for PUL.

SEARCH STRATEGY

MEDLINE, COCHRANE and DARE databases were searched from 1 January 1984 to 31 January 2017. The primary outcome was accurate risk prediction of women initially diagnosed with a PUL having an ectopic pregnancy (high risk) as opposed to either a failed PUL or intrauterine pregnancy (low risk).

SELECTION CRITERIA

All studies written in the English language, which were not case reports or series that assessed women classified as having a PUL at initial ultrasound.

DATA COLLECTION AND ANALYSIS

Forty-three studies were included. QUADAS-2 criteria were used to assess the risk of bias. We used a novel, linear mixed-effects model and constructed summary receiver operating characteristic curves for the thresholds of interest.

MAIN RESULTS

There was a high risk of differential verification bias in most studies. Meta-analyses of accuracy were performed on (i) single human chorionic gonadotrophin (hCG) cut-off levels, (ii) hCG ratio (hCG at 48 hours/initial hCG), (iii) single progesterone cut-off levels and (iv) the 'M4 model' (a logistic regression model based on the initial hCG and hCG ratio). For predicting an ectopic pregnancy, the areas under the curves (95% CI) for these four management protocols were as follows: (i) 0.42 (0.00-0.99), (ii) 0.69 (0.57-0.78), (iii) 0.69 (0.54-0.81) and (iv) 0.87 (0.83-0.91), respectively.

CONCLUSIONS

The M4 model was the best available method for predicting a final outcome of ectopic pregnancy. Developing and validating risk prediction models may optimise the management of PUL.

TWEETABLE ABSTRACT

Pregnancy of unknown location meta-analysis: M4 model has best test performance to predict ectopic pregnancy.

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.

Individualisation of intervention for tubal ectopic pregnancy: historical perspectives and the modern evidence based management of ectopic pregnancy

Historically, ectopic pregnancy was a life-threatening condition where diagnosis was possible only at post mortem or laparotomy and maternal mortality was up to 90%. The evolution in the management of ectopic pregnancy has meant that diagnosis can be made using non-invasive techniques with an aim to identify the ectopic gestation before tubal rupture. This enables health care professionals to offer management options that consider not only maternal mortality, but morbidity and fertility outcomes as well. In spite of this, diagnostic techniques and management options are not without limitations. Research is currently focused on new tests with a single diagnostic capability, diagnostic and treatment algorithms and safe methods of triaging patients. This article aims to review the current literature on the diagnosis and management of ectopic pregnancy and to formulate a pathway to help individualise care and achieve the best possible outcome.

MicroRNA and implantation

We provide a review of microRNA (miRNA) related to human implantation which shows the potential diagnostic role of miRNAs in impaired endometrial receptivity, altered embryo development, implantation failure after assisted reproduction technology, and in ectopic pregnancy and pregnancies of unknown location. MicroRNAs may be emerging diagnostic markers and potential therapeutic tools for understanding implantation disorders. However, further research is needed before miRNAs can be used in clinical practice for identifying and treating implantation failure.

Ectopic pregnancy: a review

PURPOSE

Ectopic pregnancy (EP) presents a major health problem for women of child-bearing age. EP refers to the pregnancy occurring outside the uterine cavity that constitutes 1.2-1.4 % of all reported pregnancies. All identified risk factors are maternal: pelvic inflammatory disease, Chlamydia trachomatis infection, smoking, tubal surgery, induced conception cycle, and endometriosis. These developments have provided the atmosphere for trials using methotrexate as a non-surgical treatment for EP. The diagnosis measure of EP is serum human chorionic gonadotropin, urinary hCGRP/i-hCG, progesterone measurement, transvaginal ultrasound scan, computed tomography, vascular endothelial growth factor, CK, disintegrin and metalloprotease-12 and hysterosalpingography. The treatment option of EP involves surgical treatment by laparotomy or laparoscopy, medical treatment is usually systemic or through local route, or by expectant treatment.

RESULTS

It was concluded that review data reflect a decrease in surgical treatment and not an actual decline in EP occurrence so that further new avenues are needed to explore early detection of the EP.

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?

The diagnostic value of a multivariate logistic regression analysis model with transvaginal power Doppler ultrasonography for the prediction of ectopic pregnancy

OBJECTIVE

A multivariate logistic regression analysis model for predicting ectopic pregnancy in women with pregnancy of unknown location was designed and evaluated clinically.

METHODS

Endometrial thickness, symmetry, resonance, pattern of echogenicity, helicine artery blood flow and blood flow resistance index (RI) in 129 patients with suspected early ectopic pregnancy were assessed by transvaginal power Doppler ultrasonography. Variables significant in univariate logistic regression analysis were included in a multivariate predictive logistic regression analysis model.

RESULTS

The final predictive model included three factors: endometrial thickness≤9 mm; a multilayered endometrial echogenicity pattern with prominent outer and midline hyperechogenic lines and an inner hypoechogenic region; and visible endometrial arterial blood flow. The area under the receiver operating characteristic curve of the model was 0.980. When RI was >0.65 and the predictive probability>0.50, diagnostic accuracy was high. The model correctly diagnosed 52/55 (94.5%) clinically confirmed ectopic pregnancy cases.

CONCLUSION

This multivariate predictive logistic regression analysis model has clinical value for the differential diagnosis of early ectopic pregnancy when the pregnancy location is unknown.

Methotrexate treatment of ectopic pregnancy: experience at nizwa hospital with literature review

OBJECTIVES

Ectopic pregnancy occurs when the embryo fails to implant within the uterine cavity. Methotrexate, a folic acid antagonist has been widely used to treat ectopic pregnancy. The aim of this study is to determine the efficacy of methotrexate treatment for ectopic pregnancies in our settings which will in-turn help us reduce maternal mortality and morbidity.

METHODS

This was a retrospective review of 60 cases of ectopic pregnancy treated with single dose methotrexate in Nizwa hospital, Oman. Demographic data, clinical presentation, treatment progress, outcome, side effects and future fertility follow up were analysed using a computer database. Selection criteria included hemodynamically stable women with ß-hcg level of ≤5000 mIU/ml, adnexal mass ≤4 cm, absent cardiac activity and hemoperitoneum less than 100 ml. Human chorionic gonadotrophin (hcg) assay and clinical presentation were used to determine cases which warranted surgical intervention.

RESULTS

The success rate of single dose methotrexate therapy in our study was 65% (n=39) and 35% (n=21) required surgical intervention compared to reported success rate of 67-100% published in various studies. Careful selection of cases and confining strictly to the criteria improved the success rate from 40% to 60% in five and half years of the study. The mean average time of resolution of ectopic pregnancy was 32 days for a single dose and 58 days for repeat second or third doses. Eight cases of pregnancy of unknown location were treated successfully with Methotrexate. No major side effects were noted. A successful fertility outcome of 30% in the first year followed by 13.3% in the subsequent second year with a secondary infertility rate of 11.6% was observed in this study.

CONCLUSION

Methotrexate treatment of ectopic pregnancies is safe and effective with no major side effects. Intramuscular methotrexate has the advantage of tubal conservation and saves patients from requiring surgery. It is easier to administer than intraoperative route, which is by laparoscopy and needs expertise. Our study showed single dose methotrexate to be an effective treatment option for selected patients with unruptured tubal ectopic pregnancy.

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.

Use of serum progesterone measurements to reduce need for follow-up in women with pregnancies of unknown location

OBJECTIVE

To assess the efficacy of a progesterone-based algorithm for the management of women with pregnancies of unknown location (PULs) and explore the feasibility of developing a single-visit strategy in those with a low risk of requiring medical intervention.

METHODS

All clinically stable women in whom pregnancy could not be identified on ultrasound scan were managed by a pre-defined protocol based on measurement of serum progesterone and beta-human chorionic gonadotropin (beta-hCG). Intervention in the form of surgery or medical treatment with methotrexate was offered to all women with persistent or worsening symptoms and non-declining serum beta-hCG. Decision-tree analysis was used to develop a protocol for the management of women with resolving pregnancies who are at low risk of requiring medical intervention.

RESULTS

1110 women were included in the data analysis: normal intrauterine pregnancy was diagnosed in 248 (22.3%; 95% CI, 19.9-24.8) women. 761 (68.6%; 95% CI, 65.8-71.3) abnormal pregnancies resolved spontaneously on expectant management, while the remaining 101 (9.1%; 95% CI, 7.4-10.8) women with abnormal pregnancies required some form of medical intervention. Intervention rates in patients presenting with initial serum progesterone levels of <or= 20 nmol/L and <or= 10 nmol/L, were 3.9% (95% CI, 2.4-5.4) and 2.1% (95% CI, 0.9-3.3), respectively. In women presenting with progesterone <or= 10 nmol/L and beta-hCG < 450 IU/L, the intervention rate was 1.3% (95% CI, 0.2-2.5).

CONCLUSION

Women with PULs with progesterone <or= 10 nmol/L at presentation are at low risk of requiring medical intervention and may not benefit from attending routine follow-up visits.

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.

The METEX study: methotrexate versus expectant management in women with ectopic pregnancy: a randomised controlled trial

BACKGROUND

Patients with ectopic pregnancy (EP) and low serum hCG concentrations and women with a pregnancy of unknown location (PUL) and plateauing serum hCG levels are commonly treated with systemic methotrexate (MTX). However, there is no evidence that treatment in these particular subgroups of women is necessary as many of these early EPs may resolve spontaneously. The aim of this study is whether expectant management in women with EP or PUL and with low but plateauing serum hCG concentrations is an alternative to MTX treatment in terms of treatment success, future pregnancy, health related quality of life and costs.

METHODS/DESIGN

A multicentre randomised controlled trial in The Netherlands. Hemodynamically stable patients with an EP visible on transvaginal ultrasound and a plateauing serum hCG concentration < 1,500 IU/L or with a persisting PUL with plateauing serum hCG concentrations < 2,000 IU/L are eligible for the trial. Patients with a viable EP, signs of tubal rupture/abdominal bleeding, or a contra-indication for MTX will not be included. Expectant management is compared with systemic MTX in a single dose intramuscular regimen (1 mg/kg) in an outpatient setting. Serum hCG levels are monitored weekly; in case of inadequately declining, systemic MTX is installed or continued. In case of hemodynamic instability and/or signs of tubal rupture, surgery is performed. The primary outcome measure is an uneventful decline of serum hCG to an undetectable level by the initial intervention. Secondary outcomes are (re)interventions (additional systemic MTX injections and/or surgery), treatment complications, health related quality of life, financial costs, and future fertility. Analysis is performed according to the intention to treat principle. Quality of life is assessed by questionnaires before and at three time points after randomisation. Costs are expressed as direct costs with data on costs and used resources in the participating centres. Fertility is assessed by questionnaires after 6, 12, 18 and 24 months. Patients' preferences will be assessed using a discrete choice experiment.

DISCUSSION

This trial will provide guidance on the present management dilemmas in women with EPs and PULs with low and plateauing serum hCG concentrations.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN 48210491.

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.

Clinical information does not improve the performance of mathematical models in predicting the outcome of pregnancies of unknown location

OBJECTIVE(S)

To see if the incorporation of clinical variables can improve the diagnostic performance of logistic regression models in the prediction of pregnancy of unknown location (PUL) outcome.

DESIGN

Prospective observational study.

SETTING

Early Pregnancy Unit, St George's Hospital, University of London, London.

PATIENT(S)

All women with a PUL were included in the final analysis. This was defined on transvaginal ultrasonography (TVS) as there being no signs of either an intra- or an extrauterine pregnancy or retained products of conception in a woman with a positive pregnancy test.

INTERVENTION(S)

Noninterventional study; all women classified with a PUL were managed expectantly.

MAIN OUTCOMES MEASURE(S)

Data were collected prospectively from women classified as having a PUL. More than 30 clinical, ultrasonographic and biochemical end points were defined and recorded for analysis (these included risk factors for ectopic pregnancy [EP] and site-specific tenderness on TVS). Women were followed until the final diagnosis was established: failing PUL, intrauterine pregnancy (IUP), or EP. A multinomial logistic regression model (M5) was developed on 197 training cases and tested prospectively on a further 173 PUL cases. The performance of M5 was evaluated using receiver operating characteristic (ROC) curves and compared with logistic regression model M4 (hCG ratio [hCG 48 h/hCG 0 h], logarithm [log] of hCG average, and quadratic effect of the hCG ratio {[hCG ratio-1.17] x [hCG ratio-1.17]}), which was previously published.

RESULT(S)

Data from 376 consecutive women with a PUL were included in the analysis: 201 in the training set (109 [55.3%] failing PUL, 76 [38.6%] IUP, and 12 [6.1%] EP; four with a persisting PUL were excluded from the analysis) and 175 in the test set (94 [54.3%] with a failing PUL, 64 [37.0%] with an IUP, and 15 [8.7%] with an ectopic pregnancy; two with a persisting PUL were excluded from analysis). The most useful independent prognostic variables for the logistic regression model, M5, were as follows: log of serum hCG average, amount of vaginal bleeding, hCG ratio, and quadratic effect of the hCG ratio. On the test set, this model gave an area under the ROC curve of 0.979 for failing PUL, 0.979 for IUP, and 0.912 for EP. This model outperformed M4, which gave areas under the ROC curve of 0.978, 0.974, and 0.900, respectively; however, this was not significant.

CONCLUSION(S)

Clinical information does not significantly improve the performance of logistic regression models in the prediction of PUL outcome. On the basis of our results, we believe that historical, examination, and ultrasonographic factors are not essential input variables in logistic regression model building in the PUL population. When approaching women with a PUL, biochemical data alone, and in particular the hCG ratio, can be used to predict PUL outcome with a high degree of certainty.

Rationalizing the follow-up of pregnancies of unknown location

BACKGROUND

To develop a strategy to rationalize the follow-up of pregnancies of unknown location (PULs) based on the predicted outcome using a mathematical model.

METHODS

Prospective interventional study. Women classified with a PUL had serum hCG levels taken at 0 and 48 h. A logistic regression model was used to predict PUL outcome at 48 h. Women were managed according to the model's prediction. If the model predicted an intrauterine pregnancy (IUP) or ectopic pregnancy (EP), women underwent a repeat scan on day 7; if the model predicted a failing PUL and the hCG ratio was also <0.87, these women were discharged; if the model predicted a failing PUL and the hCG ratio was > or =0.87, serum hCG was repeated on day 7.

RESULTS

Three hundred and sixty-three PULs were included; the final clinical outcomes were 22 (63.1%) failing PULs, 111 (30.6%) IUPs and 23 (6.3%) EPs. 88.7% (322/363) had the location of their pregnancy confirmed in the time period according to the study protocol, i.e. day 2 for failing PULs, day 7 for IUPs and EPs. By day 7, 97.5% (354/363) had been given a diagnosis and could be eliminated from any further follow-up. Only one woman (0.3%) underwent surgical intervention for the diagnosis of her pregnancy location-a diagnostic laparoscopy and surgical evacuation.

CONCLUSION

The logistic regression model developed could be used as a basis on which to rationalize the management of PULs as it can successfully minimize their follow-up by reducing the number of visits, scans and blood tests, as well as intervention rates.

Prospective cross-validation of three methods of predicting failing pregnancies of unknown location

BACKGROUND

We compared the performance of each of three tests for predicting pregnancy failure in the pregnancy of unknown (PUL) population.

METHODS

In a prospective observational study, we compared the performance of three models for the prediction of pregnancy failure in women with a PUL: (i) logistic-regression model incorporating vaginal bleeding, endometrial thickness (ET), initial serum progesterone and hCG levels; (ii) serum progesterone at 0 h; and (3) the hCG ratio.

RESULTS

A total of 5942 consecutive pregnant women attending the Early Pregnancy Unit were scanned and 439 (7.4%) were classified as PULs. Of these women, 420 had complete data for serum hCG at 0 and 48 h, the hCG ratio, serum progesterone at 0 h, vaginal bleeding and ET. The final outcomes were 219 (52.1%) failing PULs, 167 (39.8%) intra-uterine pregnancies and 34 (8.1%) ectopic pregnancies. For the prediction of pregnancy failure in the PUL population, the area under the receiver operating characteristic (ROC) curve (AUC) for the logistic-regression model was 0.907 (Standard error (SE) 0.015), the AUC for serum progesterone was 0.952 (SE 0.010) and the AUC for the hCG ratio was 0.980 (SE 0.004). This improved performance of the hCG ratio was significant when compared with that of initial serum progesterone (P = 0.0076) and the logistic-regression model (P < 0.0001). Using the hCG ratio cut-offs of < 0.87 and <or=0.79, the serum progesterone cut-off of < 20 nmol l(-1) and the logistic-regression cut-off of >70% for the prediction of failing PUL, sensitivities were 86.3 and 82.2% (S), 87.2% (NS) and 78.1% (S), specificities were 97.0 and 98.0% (NS), 89.6% (S) and 88.6% (S), positive-likelihood ratios were 28.91, 41.30, 8.34 and 6.82 and negative-likelihood ratios were 0.14, 0.18, 0.14 and 0.25, respectively.

CONCLUSION

The hCG ratio seems to be an optimal test for the prediction of pregnancy failure in a PUL population. The hCG ratio cut-off of 0.79 is recommended on the basis of minimizing risk to those PULs discharged at 48 h. Most importantly, when the hCG ratio is below a particular cut-off, these women can be discharged at 48 h without intervention and need for further follow-up.

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

BACKGROUND

The aim of this study was to generate and evaluate a new protocol that defined non-viability in the pregnancy of unknown location (PUL) population and therefore ensured no viable intra-uterine pregnancy (IUP) would be interrupted if uterine curettage was performed. A secondary aim was to evaluate published biochemical criteria that define non-viability in a PUL population to establish if these criteria could result in inadvertent termination of pregnancy (TOP) if uterine curettage was performed.

METHODS

All clinically stable women classified as having a PUL were included in this study. Protocol 1 was developed retrospectively based on data from 500 consecutive PULs. Using this protocol, no cases of viable IUPs would undergo uterine curettage and the potential for TOP was eliminated. This protocol was then validated prospectively on the data from a further 503 consecutive PULs. Results were then compared with three established criteria (Protocols 2-4) for the use of uterine curettage as a diagnostic tool to classify the location of PULs. Protocol 2 defined non-viability when the hCG ratio (hCG at 48 h/hCG at 0 h) was <or=1.66; Protocol 3 advised uterine curettage at serum hCG levels of >or=2000 U/l or when the initial serum hCG was <2000 U/l with a serum hCG rise of <35% over 48 h (hCG ratio<1.35); Protocol 4 advised uterine curettage with a serum hCG rise of <50% over 48 h (hCG ratio<1.50). The number of uterine curettages performed and viable IUPs that would have undergone an unplanned TOP were recorded for all protocols.

RESULTS

A total of 12 572 consecutive women were scanned: 1003 (8.0%) women were classified as PULs. Training set consisted of 500 PULs: 278 (55.6%) failing PULs, 176 (35.2%) IUPs and 46 (9.2%) ectopic pregnancies (EPs). Test set consisted of 503 PULs: 255 (50.7%) failing PULs, 203 (40.4%) IUPs and 45 (9.0%) EPs. Protocol 1 when developed retrospectively on the training set would have resulted in 293 uterine curettages and no potential TOP. Protocol 1 tested prospectively on 503 PULs would have resulted in 272 uterine curettages and no potential TOP. Three established criteria were tested on the entire data set (n=1003). Protocol 2 would have resulted in 114 uterine curettages and 14 (12.3%) potential TOPs; Protocol 3 would have led to 611 uterine curettages and seven (1.2%) potential TOPs; Protocol 4 would have resulted in 617 uterine curettages and three (0.5%) potential TOPs. No harm came to the women whose EP diagnosis was delayed.

CONCLUSIONS

Established criteria for the use of uterine curettage in the management of PULs, including those advocated by the American Society for Reproductive Medicine (ASRM), can theoretically result in an inadvertent TOPs. On the basis of these data, a change in contemporary clinical practice should be considered to avoid further damage to wanted pregnancies. We conclude that uterine curettage should not be used in the routine diagnostic workup of women with a PUL.

General obstetrics: Failing pregnancies of unknown location: a prospective evaluation of the human chorionic gonadotrophin ratio

OBJECTIVE

To assess the performance of the human chorionic gonadotrophin (hCG) ratio (hCG 48 hours/hCG 0 hour) to predict spontaneous resolution of pregnancies of unknown location (PUL).

DESIGN

Prospective cohort study.

SETTING

Teaching Hospital Early Pregnancy Unit.

POPULATION

Women classified as having a PUL.

METHODS

The optimal cutoff value for hCG ratio (serum hCG at 48 hours/serum hCG at 0 hours) was calculated from data on 189 consecutive PULs (the 'training set'). This cutoff was tested prospectively on a further 200 consecutive PULs (the 'test set'). The hCG ratio was also compared to absolute levels of serum hCG at 0 and 48 hour for the prediction of failing PULs.

MAIN OUTCOME MEASURES

hCG ratio in spontaneously resolving ('failing') PUL compared with those requiring intervention. Optimum cutoff determined and tested to predict spontaneously resolving PUL. Comparison of hCG ratio with absolute levels of serum hCG.

RESULTS

A total of 3996 consecutive women were scanned, of which 438 (11.0%) were classified as PULs. Complete data were available for 389 women: 189 in the training set and 200 in the test set. In the training set, there were 102 (54%) failing PUL, while 109 (55%) in the test set. hCG ratio of <0.87 predicted failing PUL, with a sensitivity of 93.1% (95% CI 85.9-97.0) and a specificity of 90.8% (95% CI 82.2-95.7) in the training set. In the test set, sensitivity was 92.7% (95% CI 85.6-96.5) and specificity was 96.7% (95% CI 90.0-99.1). The hCG ratio outperformed absolute serum hCG levels at 0 and 48 hours.

CONCLUSIONS

We have defined the optimal hCG ratio for the prediction of failing PUL. Using this cutoff, clinicians can safely adopt a noninterventional approach in women with PUL.

Predicting the outcome of pregnancies of unknown location: Bayesian networks with expert prior information compared to logistic regression

BACKGROUND

As women present at earlier gestations to early pregnancy units (EPUs), the number of women diagnosed with a pregnancy of unknown location (PUL) increases. Some of these women will have an ectopic pregnancy (EP), and it is this group in the PUL population that poses the greatest concern. The aim of this study was to develop Bayesian networks to predict EPs in the PUL population.

METHODS

Data were gathered in a single EPU from all women with a PUL. This data set was divided into a model-building (599 women with 44 EPs) and a validation (257 women with 22 EPs) data set and consisted of the following variables: vaginal bleeding, fluid in the pouch of Douglas, midline echo, lower abdominal pain, age, endometrial thickness, gestation days, the ratio of HCG at 48 and 0 h, progesterone levels (0 and 48 h) and the clinical outcome of the PUL. We developed Bayesian networks with expert information using this data set to predict EPs.

RESULTS

The best Bayesian network used the gestational age, HCG ratio and the progesterone level at 48 h and had an area under the receiver operator characteristic curve (AUC) of 0.88 for predicting EPs when tested prospectively.

CONCLUSIONS

Discrete-valued Bayesian networks are more complex to build than, for example, logistic regression. Nevertheless, we have demonstrated that such models can be used to predict EPs in a PUL population. Prospective interventional multicentre studies are needed to validate the use of such models in clinical practice.

The conservative management of cervical ectopic pregnancies

OBJECTIVE

To evaluate the role of conservative management in the treatment of cervical ectopic pregnancies.

METHODS

This was a retrospective analysis of all cervical ectopic pregnancies diagnosed in women attending our early pregnancy unit between April 1997 and September 2004 inclusive. The diagnosis of cervical ectopic pregnancy was made using transvaginal ultrasound. Clinical and demographic data were recorded in all cases. Serum human chorionic gonadotropin levels were measured at presentation and monitored subsequently to determine the rate of successful resolution. Conservative management was in the form of medical or expectant management. Medical management involved administration of systemic or intra-amniotic methotrexate, with or without intra-amniotic potassium chloride. Systemic methotrexate was either a single dose of 50 mg/m2 or an alternate-day regimen of methotrexate at 1 mg/kg (days 1,3,5) with folinic acid rescue (days 2,4,6). If intra-amniotic treatment was required, this was either 50 mg methotrexate or 5 mmol/L potassium chloride.

RESULTS

Seven cervical ectopic pregnancies were diagnosed during the study period. Three cases were managed successfully with a single dose of methotrexate. One case was managed successfully using a multiple-dose methotrexate regimen. Another case failed medical management with both the single- and multiple-dose regimens but was successfully treated after potassium chloride was given intra-amniotically under ultrasound guidance. One case was successfully treated with intra-amniotic methotrexate and another was managed expectantly. There was no associated morbidity or mortality during the study period. We also performed a review of the current literature.

CONCLUSION

The conservative management of cervical ectopic pregnancy is effective and safe.

The practical application of a mathematical model to predict the outcome of pregnancies of unknown location

OBJECTIVE

A logistic regression model has been developed previously to predict which pregnancies of unknown location (PULs) become ectopics. This model was based on the human chorionic gonadotropin (hCG) ratio (hCG 48 h/hCG 0 h). The aim of this study was to evaluate the model in an early pregnancy clinical setting.

METHODS

This was a prospective non-interventional observational study. Women classified as having a PUL had serum hCG and progesterone levels taken at presentation and 48 h later. At 48 h, nurse practitioners in the early pregnancy unit gave their subjective assessment of the likely pregnancy outcome based upon existing strategies to predict the outcome of PULs and their own previous experience. This was used as the basis for the clinical management of the women. The hormonal data were then entered into the model, which was available on the clinic computer in the form of a Microsoft Excel package, and the predicted outcome according to this model was recorded for each case. The model was weighted in favor of detecting an ectopic pregnancy at the expense of failing PULs and intrauterine pregnancies. All women were followed up until the final true diagnosis was established: a failing PUL, an intrauterine pregnancy or an ectopic pregnancy. The predicted outcome according to the model was compared with that of the subjective assessment of the expert operator and the true outcome after follow-up.

RESULTS

Data were obtained from 357 women classified as having PULs. The final clinical outcomes were: 162 (45.4%) failing PULs, 166 (46.5%) intrauterine pregnancies and 29 (8.1%) ectopic pregnancies. Subjective assessment utilizing current strategies gave sensitivities of 79.3%, 92.8% and 87.0% for the detection of ectopic pregnancy, intrauterine pregnancy and failing PUL, respectively. The model detected ectopic pregnancy, intrauterine pregnancy and failing PUL with sensitivities of 82.8%, 86.8% and 73.5%, respectively. There were no adverse outcomes.

CONCLUSION

This logistic regression model, based on the hCG ratio, can be used to predict the outcome of PULs, especially the ectopic pregnancies, with a high degree of certainty. It compares favorably with subjective assessment by experienced operators using current strategies to predict the outcome of PULs. The model can be used by those with limited knowledge or understanding of the behavior of serum biochemistry in the first trimester and in turn aid in the classification of PULs into those at low and those at high risk of ectopic pregnancy at 48 h.

Pregnancies of unknown location: diagnostic dilemmas and management

PURPOSE OF REVIEW

This review discusses various aspects of the management of women with pregnancies of unknown location.

RECENT FINDINGS

The prevalence of pregnancies of unknown location is dependent on the quality of scanning for a given early-pregnancy unit. The higher the quality of scanning, the better the detection of ectopic pregnancy using ultrasound as a single diagnostic test, which in turn results in fewer women being classified with a pregnancy of unknown location. Varying the discriminatory zone does not significantly improve the detection of ectopic pregnancies in a pregnancy of unknown location population. A single serum human chorionic gonadotrophin, when used in a specialized transvaginal scanning unit, is not only potentially falsely reassuring but also unhelpful in excluding the presence of an ectopic pregnancy. A single-visit approach has also been shown to be ineffective. The vast majority of women with a pregnancy of unknown location are at low-risk for ectopic pregnancy. Traditional strategies are capable of detecting the failing pregnancies of unknown location and intra-uterine pregnancies within a pregnancy of unknown location population, but they lack sensitivity for detecting ectopic pregnancies. This justifies the recent development and use of mathematical modelling techniques to predict ectopic pregnancies in the pregnancies of unknown location population.

SUMMARY

New mathematical models have been developed to predict the outcome of pregnancies of unknown location; however, prospective studies are needed to assess the reproducibility of these models in different centres on different populations. Hopefully such models will enable the clinician to correctly classify pregnancies of unknown location earlier, in turn reducing the number of follow-up visits.

Diagnostic accuracy of varying discriminatory zones for the prediction of ectopic pregnancy in women with a pregnancy of unknown location

OBJECTIVES

Various serum human chorionic gonadotropin (hCG) discriminatory zones are currently used for evaluating the likelihood of an ectopic pregnancy in women classified as having a pregnancy of unknown location (PUL) following a transvaginal ultrasound examination. We evaluated the diagnostic accuracy of discriminatory zones for serum hCG levels of > 1000 IU/L, 1500 IU/L and 2000 IU/L for the detection of ectopic pregnancy in such women.

METHODS

This was a prospective observational study of women who were assessed in a specialized transvaginal scanning unit. All women with a PUL had serum hCG measured at presentation. Expectant management of PULs was adopted. These women were followed up with transvaginal ultrasound, monitoring of serum hormone levels and laparoscopy until a final diagnosis was established: a failing PUL, an intrauterine pregnancy (IUP), an ectopic pregnancy or a persisting PUL. The persisting PULs probably represented ectopic pregnancies which had been missed on ultrasound and these were incorporated into the ectopic pregnancy group. Three different discriminatory zones (1000 IU/L, 1500 IU/L and 2000 IU/L) were evaluated for predicting ectopic pregnancy in this PUL population.

RESULTS

A total of 5544 consecutive women presented to the early pregnancy unit between 25 June 2001 and 14 April 2003. Of these, 569 (10.3%) women were classified as having a PUL, 42 of which were lost to follow up. Of the 527 (9.5%) cases with PUL analyzed, there were 300 (56.9%) failing PULs, 181 (34.3%) IUPs and 46 (8.7%) ectopic pregnancies. Overall, 74.6% were symptomatic and 25.4% were asymptomatic (P = 8.825E-07). The sensitivity and specificity of an hCG level of > 1000 IU/L to detect ectopic pregnancy were 21.7% (10/46) and 87.3% (420/481), respectively; for an hCG level of > 1500 IU/L these values were 15.2% (7/46) and 93.4% (449/481), respectively, and for an hCG level of > 2000 IU/L they were 10.9% (5/46) and 95.2% (458/481), respectively.

CONCLUSIONS

Varying the discriminatory zone does not significantly improve the detection of ectopic pregnancy in a PUL population. A single measurement of serum hCG is not only potentially falsely reassuring but also unhelpful in excluding the presence of an ectopic pregnancy.

Do levels of serum cancer antigen 125 and creatine kinase predict the outcome in pregnancies of unknown location?

BACKGROUND

The aim of this study was to evaluate the role of maternal serum cancer antigen 125 (CA 125) and creatine kinase (CK) levels in predicting the outcome of pregnancies of unknown location (PUL).

METHODS

Prospective observational study. Women classified as PUL were recruited. Final outcome of each PUL was established: failing PUL, intrauterine pregnancy (IUP), ectopic pregnancy (EP) or persisting PUL. The persisting PUL group almost certainly represent ultrasonically missed EP and were included in EP group. Serum CK and CA 125 were measured at 0 and 48 h. The values at presentation and the change in levels after 2 days were used in the analysis. We incorporated the most significant of variables into a multinomial logistic regression model to predict all outcomes. The performance of this model was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

In all, 4698 consecutive women were scanned; 403 were classified as PUL, 27 were lost to follow-up. Of the 376 women eligible, 297 had complete data and therefore were recruited. Mean age and mean gestation were 30.0 years and 43.3 days respectively. Final outcomes: 153 failing PUL (51.5%), 116 IUP (39.1%) and 28 EP (9.4%). Mean serum CK levels at 0 and 48 h were 88.5 and 86.8 IU/l respectively. Mean serum CA 125 levels at 0 and 48 h were 43.8 and 40.1 kIU/l respectively. 81.1% of women had CK and CA 125 ratios (CK 48 h/CK 0 h, CA 125 48 h/CA125 0 h) between 0.7 and 1.3. CA 125 ratio was the only significant variable in the three outcome groups (P < 0.0001). Logistic regression analysis incorporating CA 125 ratio gave an area under ROC curve of 0.782 (SE = 0.041) for failing PUL, 0.768 (SE = 0.043) for IUP and 0.560 (SE = 0.078) for EP. This model was capable of distinguishing failing PUL from IUP, but was not able to detect EP.

CONCLUSIONS

Absolute levels of serum CK and CA 125 at the defined times cannot be used to predict the outcome of PUL. Although the CA 125 ratio when incorporated into logistic regression model can distinguish failing PUL from IUP, its inability to detect the high risk PUL, i.e. the developing EP, renders it inappropriate for use in the clinical setting.