Salivary progesterone as a biochemical marker to predict early preterm birth in asymptomatic high-risk women

ADAPTATION OF A POINT-OF-CARE CANINE PROGESTERONE TEST FOR USE OF PARTURITION PREDICTION IN CAPTIVE ASIAN ELEPHANTS (ELEPHAS MAXIMUS): PROOF OF CONCEPT

In the Asian elephant (Elephas maximus), the levels of progesterone products 5α-pregnane, 3α-hydroxypregnane, and 17α-progesterone are elevated during pregnancy. Detection of a sudden decrease in blood progesterone product levels in the final days of pregnancy is considered an objective way of predicting impending parturition. Point-of-care (POC) tests eliminate the cost involved in transporting samples to an external laboratory and provide an almost instant result, facilitating decision-making for animal monitoring and management. This proof-of-concept study aims to investigate the ability of the AgPlus POC immunoassay system to measure 4-pregnen-3,20-dione in pregnant elephant serum samples and adapt the method for detection of the preparturient progesterone decrease. Frozen serum samples of two pregnant elephants (N = 82) and fresh serum samples of one pregnant elephant (N = 10) were analyzed using both the POC method and a radioimmunoassay in a reference laboratory. Statistical analysis of the data showed that there was no significant difference between the two methods for detection of the progesterone drop, indicating that the POC method can be considered appropriate for use in elephant parturition prediction. Refinement of the methodology, an increase of sample size, and temporal tandem radioimmunoassay would be required to further validate this method for use in elephant reproductive management.

Diurnal variation in salivary progesterone in fertile Indian women

Research question

Is there a diurnal variation in salivary progesterone levels during menstrual cycle among Indian women?

Design

A longitudinal study was carried out to measure progesterone in saliva among small cross-sectional sample (n = 31) of fertile Indian women of reproductive age comprising young adults (18-25 years, n = 11), adults (26-38 years, n = 9) and middle aged (39-45 years, n = 11). Saliva samples were collected twice daily (morning and evening) across the entire menstrual cycle of 31 women.

Results

Mean ages at enrolment and menarche were 30.6 years and 13.6 years respectively. Fifty-five percent of the women were married. The menstrual cycle range was 20-40 days. After controlling for age and menstrual cycle length, statistically significant diurnal variation in progesterone levels was observed across menstrual cycles with high levels in the morning.

Conclusions

This is the first report on salivary progesterone in subjects with Indian ethnicity and could have clinical implications for designing point of care kits for menstrual cycle management, fertility and reproduction.

Delivery prediction by quantitative analysis of four steroid metabolites with liquid chromatography tandem mass spectrometry in asymptomatic pregnant women

BACKGROUND

Prediction of delivery is important for assessing due dates, providing adequate prenatal care, and suggesting appropriate interventions in preterm and post-term pregnancies. Recent metabolomic findings suggested that the temporal abundance information of metabolome can be used to predict delivery timing with high accuracy in a cohort of healthy women. However, a targeted and quantitative assay is required to further validate the clinical performance and utility of this group of metabolomic candidates in delivery prediction with a larger and independent cohort.

METHOD

LC-MS/MS quantitative assays were applied to determine the plasma concentrations of four steroid metabolites, including oestriol-16-glucuronide (E3-16-Gluc), 17-alpha-hydroxyprogesterone (17-OHP), tetrahydrodeoxycorticosterone (THDOC), and androstane-3,17-diol (A-3,17-Diol) in asymptomatic women of singleton pregnancies (≥30^th gestational weeks). Subsequent statistical analysis was conducted to assess the performance of the above candidates in delivery prediction.

RESULT

Using LC-MS/MS, four steroids were separated and quantified in 5.5 min. The coefficients of variation (CVs) of the four analytes at the lower limit of quantification ranged from 7.9% to 14.6%, with the R² values greater than 0.990 in the calibration curves. Of the 585 recruited pregnant women who ended up with spontaneous delivery, 17.1% and 82.9% of the subjects delivered within and after 7 days since plasma collection, respectively. In the receiver operator curve analysis, the gestational age-adjusted area under the curve of the combined measurements of E3-16-Gluc and 17-OHP was 0.69 (95% CI: 0.60-0.76), with the sensitivity of 87.0% (95% CI: 78.8%-92.9%) and specificity of 60.2% (95% CI: 55.7%-64.6%). Moreover, the positive and the negative predictive values were 28.3%-34.0% and 93.1%-97.4% respectively for this combined panel.

CONCLUSION

We performed analytical and clinical validation of a quantitation LC-MS/MS panel for the four steroids in the plasma of pregnant women. The steroid metabolites panel of E3-16-Gluc and 17-OHP was potentially useful for predicting delivery within one week in asymptomatic women of singleton pregnancies. Key messagesA quantitative LC-MS/MS assay for determining the plasma levels of 17-OHP, THDOC, A-3,17-Diol and E3-16-Gluc was developed and validated, in order to evaluate their predictive performance in asymptomatic delivery of singleton pregnancy. The levels of E3-16-Gluc and 17-OHP were found to be significantly elevated at the time of sampling in women that delivered within one week and their combinational testing may be potentially useful in delivery prediction.

Biomarkers for Preterm Delivery

Preterm birth occurring before the thirty-seventh gestational week complicates 4.5%-18% of pregnancies worldwide. The pathogenesis of spontaneous preterm delivery is not fully understood. Among the factors held to be responsible for its pathogenesis, the most emphasized is the inflammatory process. Studies in terms of the prediction of preterm delivery are basically divided into 3 categories: 1) Prediction in pregnant women who are asymptomatic and without risk factors, 2) Prediction in pregnant women who are asymptomatic and have risk factors, 3) Prediction in symptomatic pregnant women who have threatened preterm labour. In this chapter, the topic of biomarkers in relation to preterm delivery is discussed. The most commonly used markers in published studies are fetal fibronectin, cervical pIGFBP-1 and cervical length measurement by transvaginal ultrasound. For prediction in symptomatic pregnant women applying to the hospital with threatened preterm labour, the markers used are fetal fibronection, insulin-like growth factors (IGFs) and inflammatory markers. Preterm labour prediction with markers checked in the first and second trimesters are fetal fibronection, insulin-like growth factors (IGFs), micro RNAs, progesterone, circulating microparticles (CMPs), inflammatory markers, matrix metalloproteinases, aneuploidy syndrome screening test parameters and other hormones.

Evaluation of trappin-2 in cervicovaginal secretions as predictor of spontaneous preterm birth in asymptomatic high-risk women: Nested case-control study

OBJECTIVE

To evaluate trappin-2 levels in cervicovaginal secretions for prediction of spontaneous preterm birth (sPTB) and compare it with transvaginal sonography (TVS) cervical length in asymptomatic women at risk of PTB.

METHODS

Trappin-2 levels assessed in cervicovaginal secretions collected from 80 asymptomatic pregnant women at high risk for preterm delivery and cervical length measured by TVS, first at 14-20 weeks of pregnancy and repeated 8 weeks later. On the basis of delivery outcomes, participants were divided into cases (delivery <37 weeks) and controls (delivery at 37-41 weeks).

RESULTS

The mean value of cervicovaginal trappin-2 was significantly higher in women who delivered preterm (n = 40), compared with the term group (n = 40: P < 0.001) both at 14-20 weeks and at 22-28 weeks. The critical cut-off value for cervicovaginal trappin-2 at 14-20 weeks was 4620 pg/mL, above which participants delivered prematurely with sensitivity, specificity, and positive and negative predictive values of 82.5%, 71.0%, 78.5%, and 81.5% respectively, whereas TVS cervical length in this window period was not significantly associated with preterm birth. At 22-28 weeks a trappin-2 value of 6900 pg/mL had similar predictive accuracy.

CONCLUSION

Raised cervicovaginal trappin-2 levels can be used as an early tool for prediction of PTB as early as 14-20 weeks (earlier than TVS) in asymptomatic high-risk women.

Reproducibility of saliva progesterone measured by immunoassay compared to liquid chromatography mass spectrometry

Immunoassay overestimates progesterone in blood, but no studies have tested whether this occurs in saliva. We measured progesterone in saliva using immunoassay and mass spectrometry. We tested the immunoassay for cross reactivity with dehydroepiandrosterone sulfate (DHEA-S) and 17α-hydroxyprogesterone (17α-OHP). Progesterone was significantly higher in immunoassay compared to mass spectrometry. Immunoassay progesterone levels increased in when incremental levels of 17α-OHP standard was added. This effect was not observed with the addition of DHEA-S. Research using salivary progesterone immunoassay techniques should be wary, particularly with individuals taking steroid supplementation or with high levels of progesterone metabolites.

Rationale & design of the PROMISES study: a prospective assessment and validation study of salivary progesterone as a test for preterm birth in pregnant women from rural India

Background

In India, 3.6 million pregnancies are affected by preterm birth annually, with many infants dying or surviving with disability. Currently, there is no simple test available for screening all women at risk of spontaneous PTB in low income setting, although high resource settings routinely use cervical length measurement and cervico-vaginal fluid fetal fibronectin for identification and care of women at risk due to clinical history. In rural India, where the public health system has limited infrastructure, trained staff and equipment, there is a greater need to develop a low-cost screening approach for providing early referral, treatment and remedial support for pregnant women at risk of preterm birth. There is interest in the use of a salivary progesterone test as a screening tool preliminary evidence from India, Egypt and UK has shown promise for this type of test. The test requires further validation in a low resource community setting.

Methods

The Promises study aims to validate and test the feasibility of introducing a low-cost salivary progesterone preterm birth prediction test in two rural districts in India with high rates of prematurity. It is a prospective study of 2000 pregnant women recruited from Panna and Satna in Madhya Pradesh over approximately 24 months. Demographic and pregnancy outcome data will be collected, and pregnancies will be dated by ultrasound sonography. Saliva progesterone will be measured by ELISA in samples obtained between 24–28 weeks of gestation. The association between salivary progesterone and preterm birth will be determined and the utility of salivary progesterone to predict preterm birth < 34, as well as < 30 and < 37 weeks assessed. Additional qualitative data will be obtained in terms of acceptability and feasibility of saliva progesterone testing and knowledge of PTB.

Discussion

A validated cost-effective saliva test, which has potential for further adaptation to a ‘point of care’ setting will allow early identification of pregnant women at risk of preterm birth, who can be linked to an effective pathway of care and support to reduce preterm birth and associated adverse consequences. This will reduce both economic and emotional burden on the affected women and their families.

Plasma progesterone, estradiol, and unconjugated estriol concentrations in twin pregnancies: Relation with cervical length and preterm delivery

INTRODUCTION

The aim of this study was to examine the association between plasma hormone concentrations, cervical length, and preterm delivery in twin pregnancies, including the effect of progesterone treatment.

MATERIAL AND METHODS

This study included 191 women pregnant with twins from a randomized placebo-controlled trial. A baseline blood sample was collected at 18-24 weeks before treatment with vaginal progesterone (n = 95) or placebo pessaries (n = 96), and 167 (87.4%) women had a second sample collected after 4-8 weeks of treatment. At baseline, 155 (81.2%) women had their cervical length measured. Progesterone, estradiol, and unconjugated estriol concentration was measured, and the association between hormone concentrations, cervical length, and gestational age at delivery was examined. Hormone concentrations were compared in the placebo and progesterone group. Statistical analysis included Spearman's rho, Mann-Whitney U test, Cuzick's test for trends, and linear regression analyses.

RESULTS

A short cervical length was associated with preterm delivery. Cervical length and hormone concentrations were not associated (Spearman's rho; progesterone -.05, estradiol .04, estriol .08). Decreasing gestational age at delivery was associated with higher progesterone and estradiol concentrations at baseline (P trend; progesterone 0.04, estradiol 0.02) but not in the second sample or in the weekly change between samples. Progesterone treatment did not increase the progesterone concentration.

CONCLUSIONS

Plasma concentrations of progesterone, estradiol, and unconjugated estriol at 18-24 weeks are not associated with cervical length or preterm delivery in twin pregnancies. Vaginal progesterone treatment does not increase the circulating progesterone concentration in twin pregnancies. Cervical length, but not hormone concentration, is predictive of preterm delivery in twin gestations.

Prediction of spontaneous preterm birth: salivary progesterone assay and transvaginal cervical length assessment after 24 weeks of gestation, another critical window of opportunity

Objectives: Measurement of salivary progesterone (SP4) levels and cervical length (CL) after 24 weeks to assess their potential predictive value among asymptomatic women at high risk of spontaneous preterm birth (PTB). Methods: This prospective observational (noninterventional) study consecutively recruited asymptomatic women at high risk of spontaneous PTB. SP4 and CL were measured at recruitment (24-28 weeks of gestation) then repeated after 3-4 weeks. All recruited women were followed up regularly till delivery. The primary outcome measure was the occurrence of spontaneous PTB. Results: One hundred and thirty four women completed the study, 22 (16.4%) and 32 (23.9%) women had early (<34 weeks) and late (≥34 weeks) PTB, respectively. Initially, the mean CL was 3.2 ± 0.6 cm and the mean SP4 was 4062.8 ± 814.6 pg/ml; with follow up, the mean CL became 3.0 ± 0.6 cm and the mean SP4 became 3871.6 ± 1136.9. Women with early PTB had significantly lower initial and follow up CL and SP4 measures when compared to women with late PTB and those who had birth at term. The rate of drop in SP4 and CL measurements between the two visits was also significantly higher among women with early PTB than those with late PTB and term birth. Receiver-operating characteristic (ROC) curves showed that, CL was a good predictor but SP4 was a better predictor of PTB as the area under the curve (AUC) for CL was less than that for SP4 at both visits (i.e. 0.858 and 0.868 versus 0.986 and 0.990 at the initial and follow up visits, respectively). There was a statistically significant correlation between CL and SP4 measurements. Multivariable binary logistic regression analysis revealed that follow up SP4 measurement was the only independent predictor of spontaneous PTB, and neither BMI, maternal age, SP4 nor CL were independent predictors of early spontaneous PTB. Conclusions: After 24 gestational weeks, SP4 assessment is a simple and reliable promising tool to predict spontaneous PTB among asymptomatic high-risk women, with a little superior performance than CL measurement.

A novel high-throughput assay for the measurement of salivary progesterone by liquid chromatography tandem mass spectrometry

Background

Liquid chromatography tandem mass spectrometry (LC-MS/MS) enables specific and sensitive quantification of steroids with a high throughput. Saliva sampling is advantageous for multisample profiling over longer periods of time, as it is non-invasive, cheap, can be carried out at home and does not require the attendance of clinical personnel. We developed a rapid LC-MS/MS for the measurement of salivary progesterone, frequently assessed as ovulation marker in patients desiring fertility.

Methods

Samples (300 μL) were prepared by supported liquid extraction using dichloromethane and were reconstituted in 40% methanol. Chromatography was performed using a C8 column with a water/methanol gradient containing 0.1% formic acid and 2 mmol/L ammonium acetate. Quantification was performed with a Waters TQ-S mass spectrometer.

Results

Total run time was 5.5 min. The lower limit of quantification was 20 pmol/L (1.2 fmol on column). Inter- and intra-assay comparison showed coefficients of variation and bias between measured and nominal concentrations of less than 11%. Mean recovery was 91%. Interference with a large set of natural and synthetic steroids was excluded. The assay was successfully applied to measure progesterone variation during the menstrual cycle ( n = 9) and diurnal variations during luteal phase ( n = 7) in regularly cycling women.

Discussion

We present a novel LC-MS/MS assay for the determination of salivary progesterone with high-throughput potential. The applicability of the assay for progesterone profiling during the menstrual cycle is demonstrated.

Imaging immunoassay in negative: surface-catalysed chemiluminescence for the detection of pregnancy hormones in artificial saliva

Before and after exposure to progesterone or œstriol – visualising the extent of antibody/antigen complexation.

Hospital admission for hyperemesis gravidarum in women at increased risk of spontaneous preterm birth

BACKGROUND

Progesterone administration prevents spontaneous preterm birth (sPTB) in women at increased risk. Progesterone concentration is lower in women with subsequent sPTB. Conversely, high concentrations of progesterone are implicated in the pathogenesis of hyperemesis gravidarum (HG). We hypothesized that women at increased risk of sPTB or spontaneous late miscarriage would be less likely to have a diagnosis of HG. To explore this hypothesis, we compared the incidence of HG in women at increased risk of sPTB and women with no identifiable risk factors.

METHODS

Women at increased risk of sPTB were identified from a specialist Preterm Birth Clinic (PTBC) database where criteria for PTBC attendance are previous cervical surgery, previous sPTB <34 weeks, previous spontaneous late miscarriage, incidental sonographic cervical shortening, and uterine anomaly. Hospital antenatal booking and coding records for the same time period were examined to identify HG admissions. Women with multiple gestations, trophoblastic disease, or pre-existing abnormal thyroid function were excluded. The incidence of HG among PTBC (n=394) and non-PTBC attendees (n=4762) was calculated.

RESULTS

The incidence of HG was lower in women at increased risk of sPTB (1.52%, n=6) compared with women with no identifiable risk factor for sPTB (3.33%, n=159; P=.049).

CONCLUSION

Hospital admission for HG is reduced in women with risk factors for sPTB compared with those without risk factors. Exploration of the pathogenesis of HG may improve understanding of the mechanisms underlying sPTB.

Bitter taste receptors as targets for tocolytics in preterm labor therapy

Preterm birth (PTB) is the leading cause of neonatal mortality and morbidity, with few prevention and treatment options. Uterine contraction is a central feature of PTB, so gaining new insights into the mechanisms of this contraction and consequently identifying novel targets for tocolytics are essential for more successful management of PTB. Here we report that myometrial cells from human and mouse express bitter taste receptors (TAS2Rs) and their canonical signaling components (i.e., G-protein gustducin and phospholipase C β2). Bitter tastants can completely relax myometrium precontracted by different uterotonics. In isolated single mouse myometrial cells, a phenotypical bitter tastant (chloroquine, ChQ) reverses the rise in intracellular Ca2+ concentration ([Ca2+]i) and cell shortening induced by uterotonics, and this reversal effect is inhibited by pertussis toxin and by genetic deletion of α-gustducin. In human myometrial cells, knockdown of TAS2R14 but not TAS2R10 inhibits ChQ's reversal effect on an oxytocin-induced rise in [Ca2+]i Finally, ChQ prevents mouse PTBs induced by bacterial endotoxin LPS or progesterone receptor antagonist mifepristone more often than current commonly used tocolytics, and this prevention is largely lost in α-gustducin-knockout mice. Collectively, our results reveal that activation of the canonical TAS2R signaling system in myometrial cells produces profound relaxation of myometrium precontracted by a broad spectrum of contractile agonists, and that targeting TAS2Rs is an attractive approach to developing effective tocolytics for PTB management.-Zheng, K., Lu, P., Delpapa, E., Bellve, K., Deng, R., Condon, J. C., Fogarty, K., Lifshitz, L. M., Simas, T. A. M., Shi, F., ZhuGe, R. Bitter taste receptors as targets for tocolytics in preterm labor therapy.

Placental hormone profiles as predictors of preterm birth in twin pregnancy: A prospective cohort study

Objective

The objective of the study was to analyse placental hormone profiles in twin pregnancies to determine if they could be used to predict preterm birth.

Study design

Progesterone, estradiol, estriol and corticotropin-releasing hormone were measured using competitive immunoassay and radioimmunoassay in serum and saliva samples of 98 women with twin pregnancies,at 3 or more gestational timepoints. Hormone profiles throughout gestation were compared between very preterm (<34 weeks; n = 8), preterm (<37 weeks; n = 40) and term (37+ weeks; n = 50) deliveries.

Results

No significant differences were found between preterm and term deliveries in either absolute hormone concentrations or ratios. Estimated hormone concentrations and ratios at 26 weeks did not appear to predict preterm delivery. Salivary and serum hormone concentrations were generally poorly correlated.

Conclusion

Our results suggest that serial progesterone, estradiol, estriol and corticotropin-releasing hormone measurements in saliva and serum are not robust biomarkers for preterm birth in twin pregnancies.

Predicting Preterm Labour: Current Status and Future Prospects

Preterm labour and birth are a major cause of perinatal morbidity and mortality. Despite modern advances in obstetric and neonatal management, the rate of preterm birth in the developed world is increasing. Yet even though numerous risk factors associated with preterm birth have been identified, the ability to accurately predict when labour will occur remains elusive, whether it is at a term or preterm gestation. In the latter case, this is likely due to the multifactorial aetiology of preterm labour wherein women may display different clinical presentations that lead to preterm birth. The discovery of novel biomarkers that could reliably identify women who will subsequently deliver preterm may allow for timely medical intervention and targeted therapeutic treatments aimed at improving maternal and fetal outcomes. Various body fluids including amniotic fluid, urine, saliva, blood (serum/plasma), and cervicovaginal fluid all provide a rich protein source of putative biochemical markers that may be causative or reflective of the various pathophysiological disorders of pregnancy, including preterm labour. This short review will highlight recent advances in the field of biomarker discovery and the utility of single and multiple biomarkers for the prediction of preterm birth in the absence of intra-amniotic infection.

Salivary progesterone and cervical length measurement as predictors of spontaneous preterm birth

OBJECTIVE

To evaluate the efficacy of salivary progesterone, cervical length measurement in predicting preterm birth (PTB).

METHODS

Prospective observational study included 240 pregnant women with gestational age (GA) 26-34 weeks classified into two equal groups; group one are high risk for PTB (those with symptoms of uterine contractions or history of one or more spontaneous preterm delivery or second trimester abortion) and group 2 are controls.

RESULTS

There was a highly significant difference between the two study groups regarding GA at delivery (31.3 ± 3.75 in high risk versus 38.5 ± 1.3 in control), cervical length measured by transvaginal ultrasound (24.7 ± 8.6 in high risk versus 40.1 ± 4.67 in control) and salivary progesterone level (728.9 ± 222.3 in high risk versus 1099.9 ± 189.4 in control; p < 0.001). There was a statistically significant difference between levels of salivary progesterone at different GA among the high risk group (p value 0.035) but not in low risk group (p value 0.492). CL measurement showed a sensitivity of 71.5% with 100% specificity, 100% PPV, 69.97% NPV and accuracy of 83%, while salivary progesterone showed a sensitivity of 84% with 90% specificity, 89.8% PPV, 85.9% NPV and accuracy of 92.2%.

CONCLUSION

The measurement of both salivary progesterone and cervical length are good predictors for development of PTB.

Dispatches from the interface of salivary bioscience and neonatal research

The emergence of the interdisciplinary field of salivary bioscience has created opportunity for neonatal researchers to measure multiple components of biological systems non-invasively in oral fluids. The implications are profound and potentially high impact. From a single oral fluid specimen, information can be obtained about a vast array of biological systems (e.g., endocrine, immune, autonomic nervous system) and the genetic polymorphisms related to individual differences in their function. The purpose of this review is to describe the state of the art for investigators interested in integrating these unique measurement tools into the current and next generation of research on gonadal steroid exposure during the prenatal and neonatal developmental periods.