Evaluation of novel biomarkers for early pregnancy outcome prediction†

OBJECTIVE

To assess performance and discriminatory capacity of commercially available enzyme-linked immunosorbent assays of biomarkers for predicting first trimester pregnancy outcome in a multi-center cohort.

DESIGN

In a case-control study at three academic centers of women with pain and bleeding in early pregnancy, enzyme-linked immunosorbent assays of biomarkers were screened for assay performance. Performance was assessed via functional sensitivity, assay reportable range, recovery/linearity, and intra-assay precision (%Coefficient of Variation). Top candidates were analyzed for discriminatory capacity for viability and location among 210 women with tubal ectopic pregnancy, viable intrauterine pregnancy, or miscarriage. Assay discrimination was assessed by visual plots, area under the curve with 95% confidence intervals, and measures of central tendency with two-sample t-tests.

RESULTS

Of 25 biomarkers evaluated, 22 demonstrated good or acceptable assay performance. Transgelin-2, oviductal glycoprotein, and integrin-linked kinase were rejected due to poor performance. The best biomarkers for discrimination of pregnancy location were pregnancy-specific beta-1-glycoprotein 9, pregnancy-specific beta-1-glycoprotein 1, insulin-like growth factor binding protein 1, kisspeptin (KISS1), pregnancy-specific beta-1-glycoprotein 3, and beta parvin (PARVB). The best biomarkers for discrimination of pregnancy viability were pregnancy-specific beta-1-glycoprotein 9, pregnancy-specific beta-1-glycoprotein 3, EH domain-containing protein 3, KISS1, WAP four-disulfide core domain protein 2 (HE4), quiescin sulfhydryl oxidase 2, and pregnancy-specific beta-1-glycoprotein 1.

CONCLUSION

Performance of commercially available enzyme-linked immunosorbent assays was acceptable for a panel of novel biomarkers to predict early pregnancy outcome. Of these, six and seven candidates demonstrated good discriminatory capacity of pregnancy location and viability, respectively, when validated in a distinct external population. Four markers demonstrated good discrimination for both location and viability.

Nanomedicines for Improved Management of Ectopic Pregnancy: A Narrative Review

Ectopic pregnancy (EP) - the implantation of an embryo outside of the endometrial cavity, often in the fallopian tube - is a significant contributor to maternal morbidity and leading cause of maternal death due to hemorrhage in first trimester. Current diagnostic modalities including human chorionic gonadotropin (hCG) quantification and ultrasonography are effective, but may still misdiagnose EP at initial examination in many cases. Depending on the patient's hemodynamic stability and gestational duration of the pregnancy, as assessed by history, hCG measurement and ultrasonography, management strategies may include expectant management, chemotherapeutic treatment using methotrexate (MTX), or surgical intervention. While these strategies are largely successful, expectant management may result in tubal rupture if the pregnancy does not resolve spontaneously; MTX administration is not always successful and may induce significant side effects; and surgical intervention may result in loss of the already-damaged fallopian tube, further hampering the patient's subsequent attempts to conceive. Nanomaterial-based technologies offer the potential to enhance delivery of diagnostic imaging contrast and therapeutic agents to more effectively and safely manage EP. The purpose of this narrative review is to summarize the current state of nanomedicine technology dedicated to its potential to improve both the diagnosis and treatment of EP.

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.

The potential value of activin B and fibronectin for the triage of pregnancies of unknown location and prediction of first trimester viability

Aim

We have assessed the potential predictive ability of the biomarkers activin B and fibronectin (FN1) alone and when added to established markers for triaging patients as being at low or high risk of ectopic pregnancy (EP). We also assessed their use as predictors of viability at 12 weeks gestation.

Methods

Exploratory secondary analysis of a prospective study including all women classified as a pregnancy of known location (PUL) based on transvaginal ultrasonography between January and December 2007 at the early pregnancy unit of St Georges' Hospital (London). We used multinomial logistic regression to assess the diagnostic potential of the biomarkers to triage PUL at high risk of complications (EP or persistent PUL), and standard binary logistic regression to predict first trimester viability at 12 weeks.

Results

For discriminating high-risk (n = 16) from low-risk PUL (n = 93), the area under the receiver operating characteristic curve (AUC) was 0.75 (95% confidence interval 0.60-0.85) for activin B and 0.55 (0.41-0.68) for FN1. Adding activin B to a multinomial logistic regression model incorporating β-hCG ratio and initial progesterone yielded odds ratios of 0.16 (0.05-0.55) for failing vs high-risk PUL and 0.29 (0.07-1.19) for intrauterine vs high-risk PUL and increased the model's AUC from 0.84 to 0.89. At a risk threshold of 5% for high-risk PUL, sensitivity increased from 84% to 87% and specificity from 48% to 64%. For discriminating viable (n = 28) from non-viable (n = 81) pregnancies at 12 weeks, both markers had an AUC of 0.54.

Conclusions

Our results suggested that activin B may be a promising marker to improve PUL triage in addition to established markers.

Association between three-dimensional transvaginal sonographic markers and outcome of pregnancy of unknown location: a pilot study

OBJECTIVE

To assess the accuracy of three-dimensional (3D) transvaginal sonographic (TVS) parameters in predicting the evolution of a pregnancy of unknown location (PUL).

METHODS

This was a prospective observational study performed at the early pregnancy unit of a university hospital from September 2008 to June 2012. Women with a positive pregnancy test without any signs of intra- or extrauterine pregnancy at their first TVS examination were considered eligible and a 3D dataset containing the entire uterus was acquired. An experienced observer analyzed all 3D datasets for assessment of the following parameters: endometrial thickness, volume, mean gray-scale index and asymmetry. Women were followed until they were classified as having: (i) non-visualized pregnancy loss (NVPL); (ii) intrauterine pregnancy (IUP); or (iii) ectopic pregnancy or persistent PUL. We compared the values of the TVS parameters across the three groups. We also assessed the area under the receiver-operating characteristics curve of the 3D-TVS parameters in comparison to that for serum β-human chorionic gonadotropin (β-hCG) ratio (48 h/baseline) to predict PUL outcome. We then evaluated whether combining the 3D-TVS parameters with serum β-hCG ratio improved the predictive accuracy for PUL outcome by performing a logistic regression analysis.

RESULTS

During the study period 4939 consecutive pregnant women presented at the unit for their initial TVS examination and 325 (7%) were classified as having a PUL, of whom 161 women were enrolled and had a 3D scan of the uterus. However, 19 were excluded because of incomplete follow-up. Data from 142 women with PUL were therefore included in the analysis and the outcomes of these women were: NVPL in 98 (69%), IUP in 27 (19%) and ectopic pregnancy + persistent PUL in 14 + 3 = 17 (12%). Endometrial thickness, endometrial volume and the proportion of women with asymmetric endometrial shape differed significantly between the outcome groups. Endometrial thickness and volume could be used as reasonable predictors of both NVPL and IUP, whereas asymmetric endometrial shape and mean gray-scale index could be used as reasonable predictors of IUP only. The best single parameter to predict PUL outcomes was the β-hCG ratio. Regression analysis demonstrated that endometrial volume and endometrial shape asymmetry added significantly to the β-hCG ratio in predicting IUP but not NVPL.

CONCLUSIONS

3D-TVS markers have a low diagnostic accuracy in predicting PUL outcome. The addition of endometrial volume and shape asymmetry improves the accuracy of the β-hCG ratio in predicting IUP. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Does adenosine deaminase activity play a role in the early diagnosis of ectopic pregnancy?

Early diagnosis of ectopic pregnancy (EP) is important due to life-threatening consequences in the first trimester of pregnancy. In this study we aimed to investigate the role of adenosine deaminase (ADA) activity in the prediction of EP. Forty-one patients with unruptured ectopic pregnancy comprised the case group and forty-two first trimester pregnant women with shown foetal heart beating in ultrasound comprised the control group. The mean ADA level in EP (10.9 ± 3.0 IU/L) was higher than that in control group (9.2 ± 3.6 IU/L) (p = 0.018). Receiver operating characteristics or ROC curve identified ADA value of 10.95 IU/L as optimal threshold for the prediction of EP with 56% sensitivity and 67% specificity. High ADA levels are valuable in the early diagnosis of EP. However more comprehensive studies are required.

Molecular diagnostics and therapeutics for ectopic pregnancy

Ectopic pregnancies are a serious gynaecological emergency that can be fatal. As such, prompt diagnosis and safe timely treatment is essential. Here, we review the literature on the development of molecularly targeted diagnostics and therapeutics for ectopic pregnancy. A blood-based biomarker that accurately identifies an ectopic pregnancy could be used to offer early diagnostic certainty in cases where ultrasound cannot determine the location of the embryo ('a pregnancy of unknown location'). Molecules examined so far can be broadly grouped into biological themes of relevance to reproduction: (i) Fallopian tube (dys)function, (ii) embryo/trophoblast growth, (iii) corpus luteum function, (iv) inflammation, (v) uterine function and (vi) angiogenesis. While a sensitive and specific biomarker for ectopic pregnancy has yet to be identified, it is possible that improvements in platform technologies or a multi-modal biomarker approach may yield an accurate diagnostic biomarker test. Furthermore, with the advent of better imaging technology, the need for a blood-based biomarker test may be superseded by improvements in ultrasound or magnetic resonance imaging technology. There have been some recent preclinical studies describing molecularly targeted therapeutic approaches for ectopic pregnancy. Notably, bench-to-bedside studies have examined the use of combination gefitinib (orally available epidermal growth factor receptor inhibitor) and methotrexate. Preclinical studies suggest that combination gefitinib and methotrexate is highly effective in inducing placental cell death, and is significantly more effective than methotrexate alone. In early human trials, encouraging preliminary efficacy data have shown that combination gefitinib and methotrexate can rapidly resolve tubal ectopic pregnancies, and large extra-tubal ectopic pregnancies. If a large clinical randomized controlled trial confirms these findings, combination gefitinib and methotrexate could become a new medical treatment option for ectopic pregnancy.

Pregnancy of unknown location

Pregnancy of unknown location (PUL) is defined as the situation when the pregnancy test is positive but there are no signs of intrauterine pregnancy or an extrauterine pregnancy via transvaginal ultra-sonography. It is not always possible to determine the location of the pregnancy in cases of PUL. The reported rate of PUL among women attending early pregnancy units varies between 5 and 42% in the literature and the frequency of PUL incidents has increased with the increase in the number of early pregnancy units. The management of PUL seems to be highly crucial in obstetrics clinics. Therefore, in the current review, issues identified from the literature related to pregnancy of unknown location, potential tools for prediction and algorithms will be discussed.

Biomarkers for ectopic pregnancy and pregnancy of unknown location

Early pregnancy failure is the most common complication of pregnancy, and 1% to 2% of all pregnancies will be ectopic. As one of the leading causes of maternal morbidity and mortality, diagnosing ectopic pregnancy and determining the fate of a pregnancy of unknown location are of great clinical concern. Several serum and plasma biomarkers for ectopic pregnancy have been investigated independently and in combination. The following is a review of the state of biomarker discovery and development for ectopic pregnancy and pregnancy of unknown location.

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.

Serum biomarkers for predicting pregnancy outcome in women undergoing IVF: human chorionic gonadotropin, progesterone, and inhibin A level at 11 days post-ET

Objective

This study was performed to assess the prognostic value of serum hCG, progesterone, and inhibin A levels measured at 11 days post-ET for predicting pregnancy outcome in women participating in IVF.

Methods

Between May 2005 and April 2008, sera were obtained from 70 infertile women who underwent IVF-ET at 11 days post-ET and stored. HCG, progesterone, and inhibin A levels were measured by commercial enzyme-linked immunosorbent assay kits. The predictive accuracy of hCG, progesterone, and inhibin A levels for establishment of intrauterine pregnancy and ongoing pregnancy was calculated by receiver-operating characteristic curve analysis.

Results

For the prediction of intrauterine and ongoing pregnancy, serum hCG was better than progesterone and inhibin A. The predictive performance of progesterone and inhibin A was similar. The serum progesterone and inhibin A levels were significantly correlated each other (r=0.915, p=0.010).

Conclusion

A single measurement of the serum hCG level is sufficient to predict pregnancy outcome in IVF-ET patients.