Factors to consider in pregnancy of unknown location

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.

Ambulatory human chorionic gonadotrophin (hCG) testing: a verification of two hCG point of care devices

OBJECTIVES

Quantitative human chorionic gonadotropin (hCG) measurements are used to manage women classified with a pregnancy of unknown location (PUL). Two point of care testing (POCT) devices that quantify hCG are commercially available. We verified the i-STAT 1 (Abbott) and the AQT 90 FLEX (Radiometer) prior to use in PUL triage.

METHODS

Tests for precision, external quality assurance (EQA), correlation, hook effect and recovery were undertaken alongside a POCT usability assessment during this prospective multi-center verification.

RESULTS

Coefficients of variation ranged between 4.0 and 5.1 % for the three i-STAT 1 internal quality control (IQC) solutions and between 6.8 and 7.3 % for the two AQT IQC solutions. Symmetric differences in POCT EQA results when compared with laboratory and EQA stock values ranged between 3.2 and 24.5 % for the i-STAT 1 and between 3.3 and 36.9 % for the AQT. Correlation coefficients (i-STAT 1: 0.96, AQT: 0.99) and goodness of fit curves (i-STAT 1: 0.92, AQT: 0.99) were excellent when using suitable whole blood samples. An hCG hook effect was noted with the i-STAT 1 between 572,194 and 799,089 IU/L, lower than the hook effect noted with the AQT, which was between 799,089 and 1,619,309 IU/L. When hematocrit concentration was considered in sample types validated for use with each device, hCG recovery was 108 % with the i-STAT 1 and 98 % with the AQT. The i-STAT 1 scored lower on usability overall (90/130) than the AQT (121/130, p<0.001, Mann-Whitney).

CONCLUSIONS

Both hCG POCT devices were verified for use in clinical practice. Practical factors must also be considered when choosing which device to use in each unit.

Updating M6 pregnancy of unknown location risk-prediction model including evaluation of clinical factors

OBJECTIVES

Ectopic pregnancy (EP) is a major high-risk outcome following a pregnancy of unknown location (PUL) classification. Biochemical markers are used to triage PUL as high vs low risk to guide appropriate follow-up. The M6 model is currently the best risk-prediction model. We aimed to update the M6 model and evaluate whether performance can be improved by including clinical factors.

METHODS

This prospective cohort study recruited consecutive PUL between January 2015 and January 2017 at eight units (Phase 1), with two centers continuing recruitment between January 2017 and March 2021 (Phase 2). Serum samples were collected routinely and sent for β-human chorionic gonadotropin (β-hCG) and progesterone measurement. Clinical factors recorded were maternal age, pain score, bleeding score and history of EP. Based on transvaginal ultrasonography and/or biochemical confirmation during follow-up, PUL were classified subsequently as failed PUL (FPUL), intrauterine pregnancy (IUP) or EP (including persistent PUL (PPUL)). The M6 models with (M6P ) and without (M6NP ) progesterone were refitted and extended with clinical factors. Model validation was performed using internal-external cross-validation (IECV) (Phase 1) and temporal external validation (EV) (Phase 2). Missing values were handled using multiple imputation.

RESULTS

Overall, 5473 PUL were recruited over both phases. A total of 709 PUL were excluded because maternal age was < 16 years or initial β-hCG was ≤ 25 IU/L, leaving 4764 (87%) PUL for analysis (2894 in Phase 1 and 1870 in Phase 2). For the refitted M6P model, the area under the receiver-operating-characteristics curve (AUC) for EP/PPUL vs IUP/FPUL was 0.89 for IECV and 0.84-0.88 for EV, with respective sensitivities of 94% and 92-93%. For the refitted M6NP model, the AUCs were 0.85 for IECV and 0.82-0.86 for EV, with respective sensitivities of 92% and 93-94%. Calibration performance was good overall, but with heterogeneity between centers. Net Benefit confirmed clinical utility. The change in AUC when M6P was extended to include maternal age, bleeding score and history of EP was between -0.02 and 0.01, depending on center and phase. The corresponding change in AUC when M6NP was extended was between -0.01 and 0.03. At the 5% threshold to define high risk of EP/PPUL, extending M6P altered sensitivity by -0.02 to -0.01, specificity by 0.03 to 0.04 and Net Benefit by -0.005 to 0.006. Extending M6NP altered sensitivity by -0.03 to -0.01, specificity by 0.05 to 0.07 and Net Benefit by -0.005 to 0.006.

CONCLUSIONS

The updated M6 model offers accurate diagnostic performance, with excellent sensitivity for EP. Adding clinical factors to the model improved performance in some centers, especially when progesterone levels were not suitable or unavailable. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Beta-human chorionic gonadotrophin point of care testing for the management of pregnancy of unknown location

RESEARCH QUESTION

Does a commercially available quantitative beta-human chorionic gonadotrophin (BHCG) point of care testing (POCT) device improve workflow management in early pregnancy by performing comparably to gold standard laboratory methods, and is the performance of a validated pregnancy of unknown location (PUL) triage strategy maintained using POCT BHCG results?

DESIGN

Women classified with a PUL between 2018 and 2021 at three early pregnancy units were included. The linear relationship of untreated whole-blood POCT and serum laboratory BHCG values was defined using coefficients and regression. Paired serial BHCG values were then incorporated into the validated M6 multinomial logistic regression model to stratify the PUL as at high risk or at low risk of clinical complications. The sensitivity and negative predictive value were assessed. The timings required for equivocal POCT and laboratory care pathways were compared.

RESULTS

A total of 462 PUL were included. The discrepancy between 571 laboratory and POCT BHCG values was -5.2% (-6.2 IU/l), with a correlation coefficient of 0.96. The 133 PUL with paired 0 and 48 h BHCG values were compared using the M6 model. The sensitivity for high-risk outcomes (96.2%) and negative predictive values (98.5%) was excellent for both. Sample receipt and laboratory processing took 135 min (421 timings), compared with 12 min (91 timings) when using POCT (P < 0.0001).

CONCLUSIONS

POCT BHCG values correlated well with laboratory testing measurements. The M6 model retained its performance when using POCT BHCG values. Using the model with POCT may improve workflow and patient care without compromising on effective PUL triage.

Telephone-Based Intervention to Improve Family Planning Care in Pregnancies of Unknown Location: Retrospective Pre-Post Study

BACKGROUND

Patients followed for a pregnancy of unknown location are generally followed by a team of clinicians through telephone calls, and their contraceptive needs at the time of pregnancy resolution may not be addressed.

OBJECTIVE

This study aimed to assess contraceptive counseling and contraceptive uptake before and after a telephone-based intervention.

METHODS

This was a retrospective pre-post study assessing pregnancy intendedness in patients with a pregnancy of unknown location and the proportion of patients who received contraceptive counseling and a contraceptive prescription before and after the initiation of a telephone-based intervention. We reviewed medical records 1 year before and 1 year after implementation of our intervention for demographic characteristics, pregnancy intendedness, pregnancy outcome, contraceptive counseling documentation, receipt of contraception, and repeat pregnancy within 6 months. We assessed the effects of an implementation strategy to address family planning needs once pregnancy was resolved by comparing the proportions of patients who were counseled and received contraception before and after our intervention was implemented. We performed logistic regression to identify associations between covariates and the outcomes of contraceptive counseling documentation and receipt of contraception.

RESULTS

Of the 220 patients in the combined cohort, the majority were Black (161/220, 73%) and ultimately had a resolved pregnancy of unknown location (162/220, 74%), and the proportion of pregnancies documented as unintended was 60% (132/220). Before our intervention, 27 of 100 (27%) patients received contraceptive counseling, compared with 94 of 120 (78%) patients after the intervention (odds ratio [OR] 9.77, 95% CI 5.26-18.16). Before the intervention, 17 of 90 (19%) patients who did not desire repeat pregnancy received contraception, compared with 32 of 86 (37%) patients after the intervention (OR 2.54, 95% CI 1.28-5.05). Our postintervention cohort had an increased odds of receiving contraceptive counseling (OR 9.77, 95% CI 5.26-18.16) and of receiving a contraceptive prescription (OR 2.54, 95% CI 1.28-5.05) compared with our preintervention cohort.

CONCLUSIONS

We found that over half of patients with a pregnancy of unknown location have an unintended pregnancy, and standardization of care through a telephone-based intervention improves contraceptive counseling and prescribing in patients with a resolved pregnancy of unknown location. This intervention could be used at any institution that follows patients with a pregnancy of unknown location remotely to improve care.

Spontaneous Pregnancy After Surgical Repair of Subseptate Uterus: A Case Report and Review of the Available Literature

Septate uterus is the most common congenital uterine malformation. It has been associated with poor reproductive outcomes, such as infertility and recurrent miscarriage, in the context of both assisted and non-assisted reproduction, though the exact underlying pathophysiological reasons remain unclear. Diagnosis is based on two-dimensional and three-dimensional ultrasound, magnetic resonance imaging, or laparoscopic/hysteroscopic findings. Hysteroscopic repair of the uterine septum has been shown to confer several benefits to reproductive outcomes, though this fact remains in question, due to inconsistent and or low-quality evidence in the medical literature. An individualized approach to the treatment of infertility patients with septate uteri is imperative, given the plethora of possible underlying factors that may complicate management. In this report, we present the case of a patient with a subseptate uterus and a history of infertility, who, following hysteroscopic metroplasty, managed to conceive and ultimately successfully deliver a healthy child.

Evaluating cut-off levels for progesterone, β human chorionic gonadotropin and β human chorionic gonadotropin ratio to exclude pregnancy viability in women with a pregnancy of unknown location: A prospective multicenter cohort study

INTRODUCTION

There is no global agreement on how to best determine pregnancy of unknown location viability and location using biomarkers. Measurements of progesterone and β human chorionic gonadotropin (βhCG) are still used in clinical practice to exclude the possibility of a viable intrauterine pregnancy (VIUP). We evaluate the predictive value of progesterone, βhCG, and βhCG ratio cut-off levels to exclude a VIUP in women with a pregnancy of unknown location.

MATERIAL AND METHODS

This was a secondary analysis of prospective multicenter study data of consecutive women with a pregnancy of unknown location between January 2015 and 2017 collected from dedicated early pregnancy assessment units of eight hospitals. Single progesterone and serial βhCG measurements were taken. Women were followed up until final pregnancy outcome between 11 and 14 weeks of gestation was confirmed using transvaginal ultrasonography: (1) VIUP, (2) non-viable intrauterine pregnancy or failed pregnancy of unknown location, and (3) ectopic pregnancy or persisting pregnancy of unknown location. The predictive value of cut-off levels for ruling out VIUP were evaluated across a range of values likely to be encountered clinically for progesterone, βhCG, and βhCG ratio.

RESULTS

Data from 2507 of 3272 (76.6%) women were suitable for analysis. All had data for βhCG levels, 2248 (89.7%) had progesterone levels, and 1809 (72.2%) had βhCG ratio. The likelihood of viability falls with the progesterone level. Although the median progesterone level associated with viability was 59 nmol/L, VIUP were identified with levels as low as 5 nmol/L. No single βhCG cut-off reliably ruled out the presence of viability with certainty, even when the level was more than 3000 IU/L, there were 39/358 (11%) women who had a VIUP. The probability of viability decreases with the βhCG ratio. Although the median βhCG ratio associated with viability was 2.26, VIUP were identified with ratios as low as 1.02. A progesterone level below 2 nmol/L and βhCG ratio below 0.87 were unlikely to be associated with viability but were not definitive when considering multiple imputation.

CONCLUSIONS

Cut-off levels for βhCG, βhCG ratio, and progesterone are not safe to be used clinically to exclude viability in early pregnancy. Although βhCG ratio and progesterone have slightly better performance in comparison, single βhCG used in this manner is highly unreliable.

Pregnancies lost and found: a quality improvement project to increase follow-up for early pregnancy complications

Pregnancy of unknown location (PUL) and medically managed ectopic pregnancy (EP) require longitudinal surveillance to avoid adverse outcomes; however, patients with PUL/EP in the United States (U.S.) are often unable to adhere to recommended treatment plans. This quality improvement (QI) project sought to improve PUL/EP follow-up using a three-pronged intervention: standardised recall procedures, direct patient-provider communication and electronic medical record (EMR) documentation templates and tracking. We compared patients with PUL/EP managed before and after the QI project. Our primary outcome was completion of PUL/EP clinical care. Demographics, initial diagnoses and adverse outcomes were similar between 87 pre-QI and 81 post-QI patients. Significantly more patients completed PUL/EP clinical care post-QI (80.2 vs. 65.5% p = .03). Post-QI, more providers contacted patients at standard intervals (100 vs. 57.1%, p < .0001), and EMR documentation was improved (100 vs. 69.0%, p < .001). Simple changes to PUL/EP management improved completion of clinical care and compliance with standardised recall and documentation.IMPACT STATEMENTWhat is already known on this subject? Pregnancy of unknown location (PUL) and medically managed ectopic pregnancy (EP) require longitudinal surveillance to avoid adverse outcomes; however, patients with PUL/EP in the United States (U.S.) are often unable to adhere to recommended treatment plans.What do the results of this study add? By standardising recall procedures, ensuring direct communication between patients and providers using a dedicated cell phone, and integrating case tracking and documentation into the electronic medical record (EMR), this quality improvement (QI) project improved completion of clinical follow-up for patients with PUL/EP (overall, 80.2 vs. 65.5% pre-QI, p=.03) and for the subgroup with medically managed EP not requiring surgery (76.5 vs. 36.4% pre-QI, p= .05). We also improved providers' compliance with standardised recall procedures and EMR documentation post-QI (p < .0001). There was no difference in the number of attempts to contact patients, or in the number of surveillance blood draws actually performed. Post-QI, survey responses indicated that patients were easily able to contact their provider and understood the importance of follow-up processes.What are the implications of these findings for clinical practice and/or research? Early pregnancy care providers can utilise simple strategies to improve follow-up of patients with PUL and medically managed EP, without increasing burdens to their health systems. Patients' favourable experiences with this management support its implementation.

Serum calponin 2 is a novel biomarker of tubal ectopic pregnancy

OBJECTIVE

To evaluate serum protein calponin 2 (CNN2) as a candidate biomarker for tubal ectopic pregnancy (EP).

DESIGN

Retrospective study.

SETTING

Single University affiliated tertiary hospital.

PATIENT(S)

Serum samples were obtained from 84 patients with EP, 39 with viable intrauterine pregnancy (vIUP), and 42 with miscarriage. Moreover, 10 fallopian tube and corresponding villous tissue samples from patients with EP, 6 villous tissue samples from patients with vIUP, and 10 villous tissue samples from patients with miscarriage were collected.

INTERVENTION(S)

Serum CNN2 concentrations were measured using enzyme-linked immunosorbent assay; CNN2 expression in tissues was evaluated via immunohistochemistry and quantitative real-time polymerase chain reaction analysis.

MAIN OUTCOME MEASURE(S)

The diagnostic performance of serum CNN2 to discriminate an EP from vIUP and miscarriage.

RESULT(S)

CNN2 was highly expressed in villous stromal cells isolated from patients with EP, and CNN2 messenger ribonucleic acid expression was upregulated in villous tissues from women with EP compared with that in women with vIUPs and miscarriages. Serum CNN2 concentration was higher in women with EP than that in women with vIUP and miscarriage. The serum CNN2 predicted EP from vIUP and miscarriage with areas under the curve (AUCs) of 0.931 (95% confidence interval: 0.889-0.975). For discriminating EP from miscarriage only, the AUC was 0.906 (95% confidence interval: 0.835-0.977). In contrast, the AUCs for serum human chorionic gonadotropin were 0.809 and 0.637, respectively.

CONCLUSION(S)

Our data highlight the possibility of serum CNN2 as a single biomarker for the diagnosis of EP.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR 1900020483.

The potential use of urinary hCG measurements in the management of pregnancies of unknown location

Multiple measurements of serum human chorionic gonadotropin (hCG) are used to predict the final pregnancy outcome for women with a pregnancy of unknown location (PUL) and monitor the management of ectopic pregnancy (EP). Urine-based testing would be more convenient and economical. This prospective cohort study involving 80 women assessed the degree of correlation between serum and urine hCG levels and whether urine hCG levels have the potential to impact clinical decision making in the management of women with a PUL. Paired urine and serum hCG measurements differed quite widely but were well correlated and the degree of correlation improved after creatinine correction. Although serial serum hCG measurements appear to be better for the overall prediction of pregnancy outcome in PUL (AUC 0.77-0.94 compared to corrected urine AUC 0.69-0.84), serial urine hCG measurements may have a role in identifying subtypes of low-risk PUL (AUC 0.83-0.84).

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.

Complications in Early Pregnancy

Early in pregnancy women frequently experience nausea, vomiting, and vaginal bleeding. Nausea and vomiting can be mild, managed by dietary modifications and medications, or severe, requiring intravenous fluids and medications. Care should be used when selecting medications for nausea to avoid additional side effects or potential harm to the developing fetus. When evaluating vaginal bleeding in early pregnancy, ectopic pregnancy must be ruled out. If an intrauterine pregnancy is seen, threatened miscarriage should be considered and the patient appropriately counseled. If neither intrauterine pregnancy nor ectopic pregnancy can be established, a management algorithm for pregnancy of unknown location is presented.

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.