Salivary progesterone and estriol among pregnant women treated with 17-alpha-hydroxyprogesterone caproate or placebo

Preference of saliva over other body fluids as samples for clinical and laboratory investigations among healthcare workers in Ibadan, Nigeria

Introduction

The study aimed to assess the knowledge and practices of clinicians and laboratory scientists on the use of saliva for clinical or laboratory tests.

Methods

This was a cross-sectional survey of health care workers (100 clinicians and 62 laboratory scientists) closely involved with specimen collection for clinical and laboratory investigation at two health facilities (secondary and tertiary) in Nigeria. Information was obtained from participants using pretested structured questionnaires. Data were analyzed with SPSS and level of significance set at p < 5%.

Results

The mean age of the study participants was 34.1 (±6.6) years. The majority (95.7%) knew saliva could be used for clinical/laboratory test. A higher proportion of laboratory scientists knew saliva could be used in diagnosing HIV (59.2%), oral diseases (88.7%), oro-facial tumors (64.4%) and genetic testing (94.5%) compared to (41%), (80%), (40%) and (80%), of clinicians respectively (p < 0.05). More clinicians (85%) indicated saliva as a good specimen for diagnosing systemic diseases compared with scientists (63%), p < 0.001. Saliva was the most comfortable/convenient body fluid to obtain from patients with more clinicians (80%) mentioning this than scientists (49.1%), p < 0.001. Twenty-six clinicians had used saliva for disease diagnosis (64%), treatment monitoring (28%) or research purposes (8%). Saliva sampling for research purposes was more prevalent among clinicians (p = 0.004).

Conclusion

The majority of the health care workers knew the various uses and advantages of saliva as a specimen for clinical and laboratory investigation. However, few indicated previous use for clinical and laboratory investigation especially in the area of research.

Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy

BACKGROUND

Multiple pregnancy is a strong risk factor for preterm birth, and more than 50% of women with a twin pregnancy will give birth prior to 37 weeks' gestation. Infants born preterm are recognised to be at increased risk of many adverse health outcomes, contributing to more than half of overall perinatal mortality. Progesterone is produced naturally in the body and has a role in maintaining pregnancy, although it is not clear whether administering progestogens to women with multiple pregnancy at high risk of early birth is effective and safe. Since publication of this new review in Issue 10, 2017, we have now moved one study (El-Refaie 2016) from included to studies awaiting classification, pending clarification about the study data.

OBJECTIVES

To assess the benefits and harms of progesterone administration for the prevention of preterm birth in women with a multiple pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (1 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the administration of a progestogen by any route for the prevention of preterm birth in women with multiple pregnancy. We did not include quasi-randomised or cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed reports identified by the search for eligibility, extracted data, assessed risk of bias and graded the quality of the evidence.

MAIN RESULTS

We included 16 trials, which all compared either vaginal or intramuscular (IM) progesterone with a placebo or no treatment, and involved a total of 4548 women. The risk of bias for the majority of included studies was low, with the exception of three studies that had inadequate blinding, or significant loss to follow-up or both, or were not reported well enough for us to make a judgement. We graded the evidence low to high quality, with downgrading for statistical heterogeneity, design limitations in some of the studies contributing data, and imprecision of the effect estimate. 1 IM progesterone versus no treatment or placebo More women delivered at less than 34 weeks' gestation in the IM progesterone group compared with placebo (risk ratio (RR) 1.54, 95% confidence interval (CI) 1.06 to 2.26; women = 399; studies = 2; low-quality evidence). Although the incidence of perinatal death in the progesterone group was higher, there was considerable uncertainty around the effect estimate and high heterogeneity between studies (average RR 1.45, 95% CI 0.60 to 3.51; infants = 3089; studies = 6; I2 = 71%; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up. There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (RR 1.05, 95% CI 0.98 to 1.13; women = 2010; studies = 5; high-quality evidence); preterm birth less than 28 weeks (RR 1.08, 95% CI 0.75 to 1.55; women = 1920; studies = 5; moderate-quality evidence); infant birthweight less than 2500 g (RR 0.99, 95% CI 0.90 to 1.08; infants = 4071; studies = 5; I2 = 76%, moderate-quality evidence)). No childhood outcomes were reported in the trials. 2 Vaginal progesterone versus no treatment or placebo by dose There were no clear group differences in incidence of preterm birth before 34 weeks (average RR 0.90, 95% CI 0.66 to 1.23; women = 1503; studies = 5; I2 = 36%; low-quality evidence). Although fewer births before 34 weeks appeared to occur in the progesterone group, the CIs crossed the line of no effect. Incidence of perinatal death was higher in the progesterone group, although there was considerable uncertainty in the effect estimate and the quality of the evidence was low for this outcome (RR 1.23, 95% CI 0.74 to 2.06; infants = 2287; studies = 3; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up. There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (average RR 0.97, 95% CI 0.89 to 1.06; women = 1597; studies = 6; moderate-quality evidence); preterm birth less than 28 weeks (RR 1.53, 95% CI 0.79 to 2.97; women = 1345; studies = 3; low-quality evidence); infant birthweight less than 2500 g (average RR 0.95, 95% CI 0.84 to 1.07; infants = 2640; studies = 3; I2 = 66%, moderate-quality evidence)). No childhood outcomes were reported in the trials. For secondary outcomes, there were no clear group differences found in any of the other maternal outcomes except for caesarean section, where women who received vaginal progesterone did not have as many caesarean sections as those in the placebo group, although the difference between groups was not large (8%) (RR 0.92, 95% CI 0.86 to 0.98; women = 1919; studies = 5; I2 = 0%). There were no clear group differences found in any of the infant outcomes except for mechanical ventilation, which was required by fewer infants whose mothers had received the vaginal progesterone (RR 0.70, 95% CI 0.52 to 0.94; infants = 2695; studies = 4).

AUTHORS' CONCLUSIONS

Overall, for women with a multiple pregnancy, the administration of progesterone (either IM or vaginal) does not appear to be associated with a reduction in risk of preterm birth or improved neonatal outcomes. Future research could focus on a comprehensive individual participant data meta-analysis including all of the available data relating to both IM and vaginal progesterone administration in women with a multiple pregnancy, before considering the need to conduct trials in subgroups of high-risk women (for example, women with a multiple pregnancy and a short cervical length identified on ultrasound).

Progestin therapy to prevent preterm birth: History and effectiveness of current strategies and development of novel approaches

In the 1930s the "progestin" hormone produced by the corpus luteum was isolated and found to be a Δ4-keto-steroid. It was aptly named progesterone (P4) and in the following 30 years the capacity of P4 and derivatives to prevent preterm birth (PTB) was examined. Outcomes of multiple small studies suggested that progestin prophylaxis beginning at mid-gestation decreases the risk for PTB. Subsequent larger trials found that prophylaxis with weekly intramuscular injections of 17α-hydroxyprogesterone caproate (17HPC) beginning at mid-gestation decreased PTB risk in women with a history of PTB. Other trials found that daily vaginal P4 prophylaxis, also beginning at mid-gestation decreased PTB risk in women with a short cervix. Currently, prophylaxis with 17HPC (in women with a history of PTB) or vaginal P4 (in women with a short cervix) are used to prevent PTB. Recent advances in understanding the molecular biology of P4 signaling in uterine cells is revealing novel progestin-based targets for PTB prevention. One possibility is to use selective P4 receptor (PR) modulators (SPRMs) to boost PR anti-inflammatory activity that blocks labor, while simultaneously preventing PR phosphorylation that causes loss of P4/PR anti-inflammatory activity. This may be achieved by SPRMs that induce a specific PR conformation that prevents site-specific serine phosphorylation that inhibits anti-inflammatory activity. Further advances in understanding how P4 promotes uterine quiescence and how its labor blocking actions are withdrawn to trigger parturition will reveal novel therapeutic targets to more effectively prevent PTB.

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.

Prenatal administration of progestogens for preventing spontaneous preterm birth in women with a multiple pregnancy

BACKGROUND

Multiple pregnancy is a strong risk factor for preterm birth, and more than 50% of women with a twin pregnancy will give birth prior to 37 weeks' gestation. Infants born preterm are recognised to be at increased risk of many adverse health outcomes, contributing to more than half of overall perinatal mortality. Progesterone is produced naturally in the body and has a role in maintaining pregnancy, although it is not clear whether administering progestogens to women with multiple pregnancy at high risk of early birth is effective and safe.

OBJECTIVES

To assess the benefits and harms of progesterone administration for the prevention of preterm birth in women with a multiple pregnancy.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (1 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the administration of a progestogen by any route for the prevention of preterm birth in women with multiple pregnancy. We did not include quasi-randomised or cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed reports identified by the search for eligibility, extracted data, assessed risk of bias and graded the quality of the evidence.

MAIN RESULTS

We included 17 trials, which all compared either vaginal or intramuscular (IM) progesterone with a placebo or no treatment, and involved a total of 4773 women. The risk of bias for the majority of included studies was low, with the exception of four studies that had inadequate blinding, or significant loss to follow-up or both, or were not reported well enough for us to make a judgement. We graded the evidence low to high quality, with downgrading for statistical heterogeneity, design limitations in some of the studies contributing data, and imprecision of the effect estimate. 1 IM progesterone versus no treatment or placeboMore women delivered at less than 34 weeks' gestation in the IM progesterone group compared with placebo (risk ratio (RR) 1.54, 95% confidence interval (CI) 1.06 to 2.26; women = 399; studies = 2; low-quality evidence). Although the incidence of perinatal death in the progesterone group was higher, there was considerable uncertainty around the effect estimate and high heterogeneity between studies (average RR 1.45, 95% CI 0.60 to 3.51; infants = 3089; studies = 6; I2 = 71%; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up.There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (RR 1.05, 95% CI 0.98 to 1.13; women = 2010; studies = 5; high-quality evidence); preterm birth less than 28 weeks (RR 1.08, 95% CI 0.75 to 1.55; women = 1920; studies = 5; moderate-quality evidence); infant birthweight less than 2500 g (RR 0.99, 95% CI 0.90 to 1.08; infants = 4071; studies = 5; I2 = 76%, moderate-quality evidence)). No childhood outcomes were reported in the trials. 2 Vaginal progesterone versus no treatment or placebo by doseThere were no clear group differences in incidence of preterm birth before 34 weeks (average RR 0.83, 95% CI 0.63 to 1.09; women = 1727; studies = 6; I2 = 46%; low-quality evidence). Although fewer births before 34 weeks appeared to occur in the progesterone group, the CIs crossed the line of no effect. Incidence of perinatal death was higher in the progesterone group, although there was considerable uncertainty in the effect estimate and the quality of the evidence was low for this outcome (RR 1.23, 95% CI 0.74 to 2.06; infants = 2287; studies = 3; low-quality evidence). No studies reported maternal mortality or major neurodevelopmental disability at childhood follow-up.There were no clear group differences found in any of the other maternal or infant outcomes (preterm birth less than 37 weeks (average RR 0.97, 95% CI 0.89 to 1.06; women = 1597; studies = 6; moderate-quality evidence); preterm birth less than 28 weeks (RR 1.22, 95% CI 0.68 to 2.21; women = 1569; studies = 4; low-quality evidence); infant birthweight less than 2500 g (RR 0.95, 95% CI 0.88 to 1.03; infants = 3079; studies = 4; I2 = 49%, moderate-quality evidence)). No childhood outcomes were reported in the trials.For secondary outcomes, there were no clear group differences found in any of the other maternal outcomes except for caesarean section, where women who received vaginal progesterone did not have as many caesarean sections as those in the placebo group, although the difference between groups was not large (7%) (RR 0.93, 95% CI 0.88 to 0.98; women = 2143; studies = 6; I2 = 0%). There were no clear group differences found in any of the infant outcomes except for mechanical ventilation, which was required by fewer infants whose mothers had received the vaginal progesterone (RR 0.61, 95% CI 0.48 to 0.77; infants = 3134; studies = 5).

AUTHORS' CONCLUSIONS

Overall, for women with a multiple pregnancy, the administration of progesterone (either IM or vaginal) does not appear to be associated with a reduction in risk of preterm birth or improved neonatal outcomes.Future research could focus on a comprehensive individual participant data meta-analysis including all of the available data relating to both IM and vaginal progesterone administration in women with a multiple pregnancy, before considering the need to conduct trials in subgroups of high-risk women (for example, women with a multiple pregnancy and a short cervical length identified on ultrasound).

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.

Regulation of progesterone signaling during pregnancy: implications for the use of progestins for the prevention of preterm birth

Preterm birth is a major cause of neonatal morbidity and mortality. Progesterone plays a critical role in suppressing the inflammatory signals that would induce parturition prior to term. Progesterone signaling is regulated in a variety of ways during pregnancy. Endocrine production of high levels of progesterone by the placenta ensures the availability of high levels of progesterone throughout pregnancy. Paracrine regulation of progesterone metabolism in target tissues, particularly the myometrium and cervix, also determines the amount of progesterone ligand available. Progesterone metabolism can also lead to the formation of metabolites that contribute to its effects. In particular, 5β-dihydroprogesterone formation by aldo-keto reductase 1D1 appears to play an important role in maintaining uterine quiescence. Progesterone signaling can also be regulated at the receptor level through changes in the relative expression of the nuclear progesterone receptor isoforms, reduced expression of membrane receptors, and changes in the expression levels of coactivators and/or corepressors, including nuclear factor κB. Progesterone and 17α-hydroxyprogesterone caproate (17OH-PC) have recently been shown to reduce preterm births in women with previous preterm birth or shortened cervix. It is important to realize that these two progestins are likely to act in significantly different ways, which will likely influence their efficacy. The structural differences and resistance to metabolism exhibited by 17OH-PC means that it will be unable to activate some of the pathways that progesterone activates, but that it also will not be subject to paracrine inactivation. The fact that progesterone therapy works for maintaining pregnancy in some women, indicates that for those women insufficient levels of progesterone ligand in target tissues is a determining factor in early parturition, despite high levels of circulating progesterone. This article is part of a Special Issue entitled 'Pregnancy and Steroids'.

Combinatory approaches prevent preterm birth profoundly exacerbated by gene-environment interactions

There are currently more than 15 million preterm births each year. We propose that gene-environment interaction is a major contributor to preterm birth. To address this experimentally, we generated a mouse model with uterine deletion of Trp53, which exhibits approximately 50% incidence of spontaneous preterm birth due to premature decidual senescence with increased mTORC1 activity and COX2 signaling. Here we provide evidence that this predisposition provoked preterm birth in 100% of females exposed to a mild inflammatory insult with LPS, revealing the high significance of gene-environment interactions in preterm birth. More intriguingly, preterm birth was rescued in LPS-treated Trp53-deficient mice when they were treated with a combination of rapamycin (mTORC1 inhibitor) and progesterone (P4), without adverse effects on maternal or fetal health. These results provide evidence for the cooperative contributions of two sites of action (decidua and ovary) toward preterm birth. Moreover, a similar signature of decidual senescence with increased mTORC1 and COX2 signaling was observed in women undergoing preterm birth. Collectively, our findings show that superimposition of inflammation on genetic predisposition results in high incidence of preterm birth and suggest that combined treatment with low doses of rapamycin and P4 may help reduce the incidence of preterm birth in high-risk women.

Prenatal administration of progesterone for preventing preterm birth in women considered to be at risk of preterm birth

BACKGROUND

Preterm birth is a major complication of pregnancy associated with perinatal mortality and morbidity. Progesterone for the prevention of preterm labour has been advocated.

OBJECTIVES

To assess the benefits and harms of progesterone for the prevention of preterm birth for women considered to be at increased risk of preterm birth and their infants.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (14 January 2013) and reviewed the reference list of all articles.

SELECTION CRITERIA

Randomised controlled trials, in which progesterone was given for preventing preterm birth.

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated trials for methodological quality and extracted data.

MAIN RESULTS

Thirty-six randomised controlled trials (8523 women and 12,515 infants) were included. Progesterone versus placebo for women with a past history of spontaneous preterm birth Progesterone was associated with a statistically significant reduction in the risk of perinatal mortality (six studies; 1453 women; risk ratio (RR) 0.50, 95% confidence interval (CI) 0.33 to 0.75), preterm birth less than 34 weeks (five studies; 602 women; average RR 0.31, 95% CI 0.14 to 0.69), infant birthweight less than 2500 g (four studies; 692 infants; RR 0.58, 95% CI 0.42 to 0.79), use of assisted ventilation (three studies; 633 women; RR 0.40, 95% CI 0.18 to 0.90), necrotising enterocolitis (three studies; 1170 women; RR 0.30, 95% CI 0.10 to 0.89), neonatal death (six studies; 1453 women; RR 0.45, 95% CI 0.27 to 0.76), admission to neonatal intensive care unit (three studies; 389 women; RR 0.24, 95% CI 0.14 to 0.40), preterm birth less than 37 weeks (10 studies; 1750 women; average RR 0.55, 95% CI 0.42 to 0.74) and a statistically significant increase in pregnancy prolongation in weeks (one study; 148 women; mean difference (MD) 4.47, 95% CI 2.15 to 6.79). No differential effects in terms of route of administration, time of commencing therapy and dose of progesterone were observed for the majority of outcomes examined. Progesterone versus placebo for women with a short cervix identified on ultrasound Progesterone was associated with a statistically significant reduction in the risk of preterm birth less than 34 weeks (two studies; 438 women; RR 0.64, 95% CI 0.45 to 0.90), preterm birth at less than 28 weeks' gestation (two studies; 1115 women; RR 0.59, 95% CI 0.37 to 0.93) and increased risk of urticaria in women when compared with placebo (one study; 654 women; RR 5.03, 95% CI 1.11 to 22.78). It was not possible to assess the effect of route of progesterone administration, gestational age at commencing therapy, or total cumulative dose of medication. Progesterone versus placebo for women with a multiple pregnancy Progesterone was associated with no statistically significant differences for the reported outcomes. Progesterone versus no treatment/placebo for women following presentation with threatened preterm labour Progesterone, was associated with a statistically significant reduction in the risk of infant birthweight less than 2500 g (one study; 70 infants; RR 0.52, 95% CI 0.28 to 0.98). Progesterone versus placebo for women with 'other' risk factors for preterm birth Progesterone, was associated with a statistically significant reduction in the risk of infant birthweight less than 2500 g (three studies; 482 infants; RR 0.48, 95% CI 0.25 to 0.91).

AUTHORS' CONCLUSIONS

The use of progesterone is associated with benefits in infant health following administration in women considered to be at increased risk of preterm birth due either to a prior preterm birth or where a short cervix has been identified on ultrasound examination. However, there is limited information available relating to longer-term infant and childhood outcomes, the assessment of which remains a priority.Further trials are required to assess the optimal timing, mode of administration and dose of administration of progesterone therapy when given to women considered to be at increased risk of early birth.

Maternal stress/distress, hormonal pathways and spontaneous preterm birth

BACKGROUND

Although second-trimester blood corticotrophin-releasing hormone (CRH) levels are robustly associated with preterm birth, the findings with respect to cortisol have been inconsistent, as have been those relating stress hormones to measured stressors and maternal distress.

METHODS

We measured plasma CRH, adrenocorticotrophic hormone (ACTH), cortisol, cortisol-binding globulin, oestradiol and progesterone at 24-26 weeks in a nested case-control study of 206 women who experienced spontaneous preterm birth and 442 term controls. We also related the hormonal levels to measures of environmental stressors, perceived stress and maternal distress (also assessed at 24-26 weeks) and to placental histopathology.

RESULTS

With the exception of an unexpectedly low oestradiol:progesterone ratio among cases (adjusted odds ratio = 0.5 [95% confidence interval 0.3, 0.8] for ratios above the median in controls), none of the hormonal measures was independently associated with spontaneous preterm birth; placental histopathological evidence of infection/inflammation, infarction or decidual vasculopathy; or measures of maternal stress or distress. CRH levels were positively associated with cortisol, but not with ACTH, whereas ACTH was also positively associated with cortisol.

CONCLUSIONS

Our findings suggest an intact pituitary-adrenal axis and confirm the positive feedback effect of cortisol on (placental) CRH. Neither of these hormonal pathways, however, was strongly linked to maternal stress/distress or to the risk of spontaneous preterm birth.

Critical appraisal of the efficacy, safety, and patient acceptability of hydroxyprogesterone caproate injection to reduce the risk of preterm birth

Prevention of preterm delivery is a major desiderate in contemporary obstetrics and a societal necessity. The means to achieve this goal remain elusive. Progesterone has been used in an attempt to prevent preterm delivery since the 1970s, but the evidence initially accumulated was fraught by mixed results and was based on mostly underpowered studies with variable eligibility criteria, including history of spontaneous abortion as an indication for treatment. More recent randomized controlled clinical trials restimulated the interest in progesterone supplementation, suggesting that progesterone may favorably influence the rate of preterm delivery. Preterm delivery is a complex disorder and consequently it is unlikely that one generalized prevention strategy will be effective in all patients. Further, an additional impediment in accepting progesterone as the "magic bullet" in the prevention of preterm delivery is that its mechanism of action is not fully understood and the optimal formulations, route of administration, and dose have yet to be established. We have concerned ourselves in this review with the most recent status of 17 alpha-hydroxyprogesterone caproate (17OH-PC) supplementation for prevention of preterm delivery. Our intention is to emphasize the efficacy, safety, and patient acceptability of this intervention, based on a comprehensive and unbiased review of the available literature. Currently there are insufficient data to suggest that 17OH-PC is superior or inferior to natural progesterone. Based on available evidence, we suggest a differential approach giving preferential consideration to either 17OH-PC or other progestins based on obstetric history and cervical surveillance. Progestin therapy for risk factors other than a history of preterm birth and/or a short cervix in the current pregnancy is not currently supported by the published evidence. The experience to date with 17OH-PC indicates that there are population subgroups that may be harmed by administration of 17OH-PC. Therefore, extending the use of 17OH-PC to unstudied populations or for indications that are not evidence-based is inadvisable outside of a research protocol.

Effect of prolonged in vivo administration of progesterone in pregnancy on myometrial gene expression, peripheral blood leukocyte activation, and circulating steroid hormone levels

OBJECTIVE

We aimed to investigate the effects of progesterone on gene expression and function of both myometrium and circulating leukocytes.

METHODS

We recruited women participating in a randomized clinical trial of progesterone to prevent preterm delivery. These participants had a twin pregnancy and were managed in 1 of 2 tertiary referral centers. Participants were treated with progesterone (90 mg vaginally) or placebo from 24 to 34 weeks of pregnancy. The outcome measures were myometrial and leukocyte gene expression and expression of cell surface markers in circulating leukocytes, all quantified ex vivo.

RESULTS

Prolonged in vivo administration of progesterone inhibited myometrial expression of connexins 26 and 43, endothelial nitric acid synthase (eNOS), and the prostaglandin receptor EP2 ex vivo. Administration of progesterone also increased numbers of circulating neutrophils while decreasing lymphocyte proportions and decreasing neutrophil CD11b expression.

CONCLUSION

The observed effects of prolonged in vivo administration of progesterone will minimize the ability of the uterus to contract as a synctium and the ability of peripheral blood leukocytes to migrate into the myometrium during parturition. We suggest that these are putative mechanisms by which progesterone might prevent preterm birth in women at high risk.

Rapid determination of natural steroidal hormones in saliva for the clinical diagnoses

Background

Saliva samples are easily collectable and non-invasive, and the monitoring of natural steroidal hormones, such as estrone (E1), 17β-estradiol (E2), estriol (E3), progesterone (P), and testosterone (T), in saliva has attracted much attention due to its numerous potential clinical and health-related applications. Because E1, E2, E3, P and T are useful indicators in numerous clinical and health-related diagnoses, there is a need for simultaneous determination.

Results

A gas chromatography-mass spectrometric assay was developed for rapid simultaneous determination of E1, E2, E3, P and T in saliva for clinical diagnoses. Extraction was achieved with a liquid extraction using 3.0 mL of pentane. The extract was dried and silylated with N-methyl-N-(trimethylsilyl) trifluoroacetamide/NH₄I (100:2) under a catalysis of 1.5% dithioerythritol for 10 min at 90°C. The accuracy of the analytes was in the range of 96% to 112% at concentrations of 0.05 and 0.10 μg/L (5.0 and 10.0 μg/L for E3), respectively, with relative standard deviations of less than 11%. The lowest quantification limits were from 0.002 to 0.6 μg/L for 1.0 mL of saliva.

Conclusion

Natural steroidal hormones were detected in the concentration ranges of nd to 0.2 μg/L in human saliva. The salivary testosterone values in the patients with prostatic carcinoma were significantly lower than in normal males. The method may useful in numerous clinical and health-related diagnoses.

17 α-Hydroxyprogesterone caproate (Makena™): in the prevention of preterm birth

17 α-hydroxyprogesterone caproate is a synthetic progestin of which there is now a US FDA-approved formulation available for intramuscular administration (Makena™) to reduce the risk of preterm birth. Intramuscular 17 α-hydroxyprogesterone caproate (identical in formulation and manufacturing process to Makena™, thus hereafter referred to as Makena™) 250 mg once weekly, initiated at 16-20 weeks' gestation, was effective in reducing the risk of preterm birth in women with a singleton pregnancy at high risk of delivering preterm in a large, well designed, placebo-controlled trial (n = 463 randomized). Rates of delivery before 37 (primary endpoint), 35, or 32 weeks' gestation were significantly lower with Makena™ than with placebo, corresponding to relative risk reductions of 34%, 33%, and 42%, respectively. The benefit of the drug in reducing the risk of preterm birth was observed when deliveries were spontaneous (but not when indicated because of complications) and regardless of maternal race. In addition, there was a significantly lower rate of several adverse fetal/neonatal outcomes among infants of women who received Makena™ than among infants of placebo recipients, including necrotizing enterocolitis, need for supplemental oxygen, birth weight of <2500 g, and intraventricular hemorrhage. Makena™ was generally well tolerated in pregnant women in this trial. Moreover, fetal exposure to the drug appeared to be safe according to a 2- to 5-year follow-up of the study, with no evidence of a detrimental effect of the drug on child neurodevelopment and a low overall incidence (≈2%) of reproductive or genital abnormalities that was not significantly different from placebo.

Pharmacokinetics of 17-hydroxyprogesterone caproate in multifetal gestation

OBJECTIVE

The purpose of this study was to define the pharmacokinetic parameters of 17-hydroxyprogesterone caproate (17-OHPC) in multifetal gestation.

STUDY DESIGN

Blood was obtained at 24-28 weeks' gestation and at 32-35 weeks gestation in 97 women with twin and 26 women with triplet gestation who were receiving 17-OHPC. Six of the women with twins had daily blood sampling for 7 days between 24 and 28 weeks' gestation, and pharmacokinetic parameters were estimated with the use of noncompartmental analysis. Modeling was applied to estimate the population parameters and to simulate various treatment scenarios.

RESULTS

The apparent half-life of 17-OHPC was 10 days. Body mass index significantly impacted 17-OHPC concentrations, but fetal number and parity did not. Apparent clearance was significantly greater in African American than in white women (P = .025).

CONCLUSION

This is the first pharmacokinetic analysis of 17-OHPC in pregnant women. Determination of half-life, covariates that affect plasma 17-OHPC concentrations, and the modeling of drug behavior provide insights into this drug's pharmacologic properties during multifetal pregnancy.

Saliva as a diagnostic fluid

Salivary diagnostics is a dynamic and emerging field utilizing nanotechnology and molecular diagnostics to aid in the diagnosis of oral and systemic diseases. In this article the author critically reviews the latest advances using oral biomarkers for disease detection. The use of oral fluids is broadening perspectives in clinical diagnosis, disease monitoring, and decision making for patient care. Important elements determining the future possibilities and challenges in this field are also discussed.

Effect of progesterone on cervical shortening in women at risk for preterm birth: secondary analysis from a multinational, randomized, double-blind, placebo-controlled trial

OBJECTIVES

To determine whether progesterone supplementation alters cervical shortening in women at increased risk for preterm birth.

METHODS

We performed a planned secondary analysis from a large, multinational preterm birth prevention trial of daily intravaginal progesterone gel, 90 mg, compared with placebo in women with a history of spontaneous preterm birth or premature cervical shortening. Transvaginal cervical length measurements were obtained in all randomized patients at baseline (18 + 0 to 22 + 6 weeks' gestation) and at 28 weeks' gestation. For this secondary analysis, the difference in cervical length between these time points was compared for the study population with a history of spontaneous preterm birth and for a population with premature cervical shortening (< or = 30 mm) at randomization. Differences between groups in cervical length for the 28-week examination were analyzed using ANCOVA, including adjustment for relevant clinical parameters and maternal characteristics.

RESULTS

Data were analyzed from 547 randomized patients with a history of preterm birth. The progesterone-treated patients had significantly less cervical shortening than the placebo group (difference 1.6 (95% CI, 0.3-3.0) mm; P = 0.02, ANCOVA). In the population of 104 subjects with premature cervical shortening at randomization, the cervical length also differed significantly on multivariable analysis, with the treatment group preserving more cervical length than the placebo group (difference 3.3 (95% CI, 0.3-6.2) mm; P = 0.03, ANCOVA), with adjustment for differences in cervical length at screening. A significant difference was also observed between groups for categorical outcomes including the frequency of cervical length progression to < or = 25 mm and a > or = 50% reduction in cervical length from baseline in this subpopulation.

CONCLUSIONS

Intravaginal progesterone enhances preservation of cervical length in women at high risk for preterm birth.

Management strategies for the prevention of preterm birth. Part I: Update on progesterone supplementation

PURPOSE OF REVIEW

Preterm birth (PTB) is the main cause of neonatal morbidity and mortality in the developed world, generating a significant public health burden. PTB is a complex disorder and it is unlikely that one generalized prevention strategy will be effective in all patients. In this review, we are concerned with the most recent status of two proposed modalities of PTB prevention: progesterone supplementation and cerclage placement. Our intention was to emphasize the differential applicability of these two interventions tailored to specific clinical presentations.

RECENT FINDINGS

Progress has been made in developing reliable prognosticators for PTB. Ultrasound cervical length measurement has emerged as the single most powerful predictor. Recent randomized trials of progesterone supplementation have indicated the relevance of this objective method of screening in the selection of patients most likely to respond to progesterone. Similarly, in studies of cerclage, cervical length has been found to perform as a tool capable of reducing unnecessary intervention.

SUMMARY

Predefined treatment strategies guiding the decision on when to proceed with medical or surgical PTB prophylaxis are still lacking. On the basis of the available evidence, we suggest a differential approach giving preferential consideration to either progesterone or cerclage based on obstetrical history, cervical surveillance, and biochemical markers of inflammation.

Patterns of plasma corticotropin-releasing hormone, progesterone, estradiol, and estriol change and the onset of human labor

CONTEXT

Clinical prediction of preterm delivery is largely ineffective, and the mechanism mediating progesterone (P) withdrawal and estrogen activation at the onset of human labor is unclear.

OBJECTIVES

Our objectives were to determine associations of rates of change of circulating maternal CRH in midpregnancy with preterm delivery, CRH with estriol (E3) concentrations in late pregnancy, and predelivery changes in the ratios of E3, estradiol (E2), and P.

DESIGN AND SETTING

A cohort of 500 pregnant women was followed from first antenatal visits to delivery during the period 2000-2004 at John Hunter Hospital, New South Wales, Australia, a tertiary care obstetric hospital.

PATIENTS

Unselected subjects were recruited (including women with multiple gestations) and serial blood samples obtained.

MAIN OUTCOME MEASURES

CRH daily percentage change in term and preterm singletons at 26 wk, ratios E3/E2, P/E3, and P/E2 and the association between E3 and CRH concentrations in the last month of pregnancy (with spontaneous labor onset) were assessed.

RESULTS

CRH percentage daily change was significantly higher in preterm than term singletons at 26 wk (medians 3.09 and 2.73; P = 0.003). In late pregnancy, CRH and E3 concentrations were significantly positively associated (P = 0.003). E3/E2 increased, P/E3 decreased, and P/E2 was unchanged in the month before delivery (medians: E3/E2, 7.04 and 10.59, P < 0.001; P/E3, 1.55 and 0.98, P < 0.001; P/E2, 11.78 and 10.79, P = 0.07).

CONCLUSIONS

The very rapid rise of CRH in late pregnancy is associated with an E3 surge and critically altered P/E3 and E3/E2 ratios that create an estrogenic environment at the onset of labor. Our evidence provides a rationale for the use of CRH in predicting preterm birth and informs approaches to delaying labor using P supplementation.

PROGESTERONE AND THE CONTROL OF HUMAN PREGNANCY AND PARTURITION

Almost 80 years ago George Corner and colleagues provided the first evidence that progesterone maintains pregnancy and that it does so, at least in part, by promoting myometrial relaxation. In the 1950s, Arpad Csapo proposed the “progesterone block hypothesis”, which posits that progesterone maintains pregnancy by promoting myometrial relaxation and that its withdrawal initiates a cascade of hormonal interactions that transforms the myometrium to a highly contractile state leading to the onset of labour. Csapo later proposed that contractility of the pregnant myometrium is determined by the balance between relaxation induced by progesterone and contraction induced by a cohort of signals including oestrogens, uterine distention and stimulatory uterotonins such as prostaglandins (PGs) and oxytocin (OT). According to this “seesaw” hypothesis, progesterone promotes myometrial relaxation by directly inducing relaxation and/or by inhibiting the production of, or myometrial responsiveness to, stimulatory uterotonins. These landmark concepts, though derived from studies of experimental animals, form the foundation for current understanding of progesterone's role in the physiology of human pregnancy. Remarkable progress has been made over the last 20–30 years in understanding the signal transduction pathways through which steroid hormones affect target cells. This knowledge has broadened the scope of Csapo's original paradigms and we are now beginning to unravel the specific signaling pathways and molecular interactions by which progesterone affects human myometrium and how its actions are controlled at the functional level. This is important for the development of progestin-based therapeutics for the prevention or suppression of preterm labour and preterm birth. Here we review recent progress in understanding the mechanisms by which progesterone sustains pregnancy and in particular how it promotes myometrial relaxation, how its relaxatory actions are nullified at parturition, and the hormonal interactions that induce progesterone withdrawal to determine the timing of human birth.

Prenatal administration of progesterone for preventing preterm birth

BACKGROUND

Preterm birth is the major complication of pregnancy associated with perinatal mortality and morbidity and occurs in up to 6% to 10% of all births. Administration of progesterone for the prevention of preterm labour has been advocated.

OBJECTIVES

To assess the benefits and harms of progesterone administration during pregnancy in the prevention of preterm birth.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Specialised Register of Controlled Trials (March 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2004), MEDLINE (1965 to January 2005), EMBASE (1988 to August 2004), and Current Contents (1997 to August 2004).

SELECTION CRITERIA

All published and unpublished randomised controlled trials, in which progesterone was given by any route for preventing preterm birth.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Collaboration and the Cochrane Pregnancy and Childbirth Group were used. Evaluation of methodological quality and trial data extraction were undertaken independently by two authors. Results are presented using relative risk with 95% confidence intervals.

MAIN RESULTS

For all women administered progesterone, there was a reduction in the risk of preterm birth less than 37 weeks (six studies, 988 participants, relative risk (RR) 0.65, 95% confidence interval (CI) 0.54 to 0.79) and preterm birth less than 34 weeks (one study, 142 participants, RR 0.15, 95% CI 0.04 to 0.64). Infants born to mothers administered progesterone were less likely to have birthweight less than 2500 grams (four studies, 763 infants, RR 0.63, 95% CI 0.49 to 0.81) or intraventricular haemorrhage (one study, 458 infants, RR 0.25, 95% CI 0.08 to 0.82). There was no difference in perinatal death between women administered progesterone and those administered placebo (five studies, 921 participants, RR 0.66, 95% CI 0.37 to 1.19). There were no other differences reported for maternal or neonatal outcomes.

AUTHORS' CONCLUSIONS

Intramuscular progesterone is associated with a reduction in the risk of preterm birth less than 37 weeks' gestation, and infant birthweight less than 2500 grams. However, other important maternal and infant outcomes have been poorly reported to date, with most outcomes reported from a single trial only (Meis 2003). It is unclear if the prolongation of gestation translates into improved maternal and longer-term infant health outcomes. Similarly, information regarding the potential harms of progesterone therapy to prevent preterm birth is limited. Further information is required about the use of vaginal progesterone in the prevention of preterm birth.