Prevention of recurrent preterm delivery by 17 alpha-hydroxyprogesterone caproate

Progestational Agents to Prevent Preterm Birth: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To perform an updated systematic review with meta-analysis to further elucidate the efficacy of progestational agents for the prevention of preterm births in patients at elevated risk.

DATA SOURCES

Computerized databases, references in published studies, and textbook chapters in all languages were used to identify randomized controlled trials (RCTs) evaluating the use of progestational agents for the prevention of preterm births in women at elevated risk.

METHODS OF STUDY SELECTION

We identified RCTs that compared progestational agents with placebo for patients at risk for preterm birth and evaluated at least one of the following: delivery before 37 weeks of gestation, birth weight less than 2,500 g, threatened preterm labor, respiratory distress syndrome, and perinatal mortality. The primary outcomes assessed were preterm delivery and perinatal mortality.

TABULATION, INTEGRATION, AND RESULTS

Ten studies met inclusion criteria for this review. For each study with binary outcomes, an odds ratio (OR) with 95% confidence intervals (CIs) was calculated for selected outcomes. Homogeneity was tested across the studies. Compared with women allocated to receive placebo, those who received progestational agents had lower rates of preterm delivery (26.2% versus 35.9%; OR 0.45, 95% CI 0.25-0.80). Similar results were noted when comparing patients who were specifically treated with 17alpha-hydroxyprogesterone caproate (29.3% versus 40.9%; OR 0.45, 95% CI 0.22-0.93). Additionally, subjects allocated to receive 17alpha-hydroxyprogesterone caproate had lower rates of birth weights less than 2,500 g (OR 0.50, 95% CI 0.36-0.71). No differences in rates of hospital admissions for threatened preterm labor or perinatal mortality were noted for subjects receiving progestational agents in general or for those receiving only 17alpha-hydroxyprogesterone caproate specifically.

CONCLUSION

The use of progestational agents and 17alpha-hydroxyprogesterone caproate reduced the incidence of preterm birth and low birth weight newborns.

Progesterone enhances the tocolytic effect of ritodrine in isolated pregnant human myometrium

OBJECTIVE

To evaluate the effect of natural progesterone on the relaxant effect of ritodrine on pregnant human oxytocin-induced myometrial contractility.

STUDY DESIGN

Isometric tension recordings were performed under physiologic conditions on isolated myometrial strips taken from low-risk term pregnant women undergoing elective cesarean section. Cumulative effects of natural progesterone (10 (-11) to 10 (-5) mol/L) on oxytocin-induced myometrial contractility were evaluated. Contractile activity following ritodrine exposure was also investigated in myometrium pretreated with natural progesterone.

RESULTS

Natural progesterone alone exerted a concentration-dependent relaxant effect on myometrial contractions. The concentration-response curve for ritodrine from natural progesterone pretreated myometrium was shifted to the left with a significant reduction ( P < .01) of 50% of the maximal response, contraction amplitude ( P < .05), and frequency ( P < .05). However, there was no significant difference in the mean maximal inhibition achieved ( P = .95).

CONCLUSION

Natural progesterone increased the relaxant effect of ritodrine by reducing 50% of the maximal response, amplitude, and frequency of myometrial contraction, most likely through nongenomic actions. These results suggest that natural progesterone may be beneficial for preventing preterm birth in a low-risk population.

Progesterone treatment to prevent preterm birth

The publication in 2003 of two large randomised trials of progesterone therapy to prevent preterm delivery has generated renewed interest in this treatment and has added substantial numbers of subjects to previously published small trials. The randomised trials of progestogens have generally shown efficacy in reducing the rate of recurrent preterm delivery in women with singleton pregnancies who were at high risk for preterm labour and delivery. Most of the successful trials have employed 17alpha-hydroxyprogesterone caproate, and one trial has reported positive results using progesterone vaginal suppositories. The administration of 17alpha-hydroxyprogesterone caproate or progesterone suppositories to women with these high-risk pregnancies showed a significant protective effect for preterm birth in six of the seven published trials. No successful trials of progestogens have been reported for women at risk for preterm delivery because of multiple gestations. Trials of progestogens after the occurrence of symptoms of labour have shown them to be ineffective in prolonging pregnancy.

17 alpha-hydroxyprogesterone caproate versus intravaginal progesterone in IVF-embryo transfer cycles: a prospective randomized study

One of the main issues in the management of IVF and embryo transfer techniques is to ensure adequate concentrations of progesterone. The aim of this prospective, randomized study was to compare the effectiveness of 17 alpha -hydroxyprogesterone caproate (17-HPC) administered intramuscularly and intra-vaginal progesterone in gel in luteal phase support in patients undergoing IVF-embryo transfer cycles. A total of 320 patients were randomly treated with either 17-HPC (341 mg i. m. every 3 days) or progesterone vaginal gel (90 mg daily). The inclusion criteria were the use of gonadotrophin-releasing hormone down-regulation and age <40 years. The outcome of IVF in both study groups was evaluated for implantation rate, biochemical pregnancy, clinical pregnancy, miscarriage, and ongoing pregnancy rate. The results of this study showed that 17-HPC conferred more benefit to IVF-embryo transfer cycles compared with intra-vaginal progesterone, as demonstrated by the results of most of the main outcome parameters considered. The data showed that 17-HPC administered every 3 days appears to be more effective in providing luteal support in comparison to intra-vaginal progesterone.

Placental protein 13 (PP-13): effects on cultured trophoblasts, and its detection in human body fluids in normal and pathological pregnancies

Placental tissue protein 13 (PP-13), one of the 56 known placental proteins identified till today, was purified from placentas obtained from women at delivery, and used to evoke antibodies against it. The purified PP-13 was lysed to peptides, which were sequenced, leading to the full-length cDNA sequencing and its expression in Escherichia coli. Sequence analysis in databases showed homology to the galectin family. Of the various antibody preparations developed, a pair of monoclonal antibodies (MAbs) coupled to the recombinant PP-13 (PP-13-R) was used for the immunodetection of PP-13 in pregnant women's serum with the solid-phase ELISA format. With a dynamic range of 25-500 pg/mL with no background in non-pregnant women's serum and men's serum, the ELISA test was suitable for the detection of PP-13 in the 1st, 2nd, and 3rd trimesters. PP-13 levels slowly increase during pregnancy. In the 1st trimester, lower than normal PP-13 levels were found in fetal growth restriction (IUGR), preeclampsia (PE), and particularly in early PE (<34 weeks of gestation). In the 2nd and 3rd trimesters, higher than normal concentrations were found in PE, IUGR and in preterm delivery (PTD). Application of PP-13 to cultured trophoblasts elicited depolarization carried by calcium ions, followed by liberation of linoleic and arachidonic acids from the trophoblast membrane, and a subsequent elevation of prostacyclin and thromboxane. These effects were negligible when PP-13 derived from the placentas of patients with IUGR, PE or PTD was used. The results are discussed in view of the potential utilization of PP-13 for early serum screening to assess the risk to develop placental insufficiency, coupled to a differential analysis of the various pathologies by analyzing cultured trophoblasts.

Functional effects of 17alpha-hydroxyprogesterone caproate (17P) on human myometrial contractility in vitro

Background

17alpha-hydroxyprogesterone caproate (17P) administration reportedly improves outcome for women with a previous spontaneous preterm delivery. This study, using in vitro strips of human uterine smooth muscle, aimed to investigate the direct non-genomic effects of 17P on spontaneous and induced contractions in tissues obtained during pregnancy, and in the non-pregnant state.

Methods

Biopsies of human myometrium were obtained at elective cesarean section, and from hysterectomy specimens, and dissected strips suspended for isometric recordings. The effects of 17P (1 nmol/L -10 micro mol/L) on spontaneous and agonist-induced (oxytocin 0.5 nmol/L for pregnant, phenylephrine 10 μmol/L for non-pregnant) contractions were measured. Integrals of contractile activity, including the mean maximal inhibition values (MMI) observed at the maximal concentration, were compared with those from simultaneously run control strips.

Results

There was no significant direct effect exerted by 17P on pregnant or non-pregnant human myometrial contractility. The MMI ± SEM for spontaneous contractions in pregnant myometrium was 4.9% ± 7.2 (n = 6; P = 0.309) and for oxytocin-induced contractions was 2.2% ± 1.3 (n = 6; P = 0.128). For non-pregnant myometrium, the MMI ± SEM for spontaneous contractions was 8.8% ± 11.0 (n = 6; P = 0.121) and for phenylephrine induced contractions was -7.9% ± 6.5 (n = 6; P = 0.966).

Conclusions

The putative benefits of 17P for preterm labor prevention are not achieved, even partially, by a direct utero-relaxant effect. These findings outline the possibility that genomic effects of 17P, achieved over long periods of administration, are required for its reported therapeutic benefits.

Epidemiology of preterm birth and neonatal outcome

In industrialized countries, 5-11% of infants are born preterm (<37 weeks' gestation), and the rate has been increasing since the early 1980s. Preterm births account for 70% of neonatal deaths and up to 75% of neonatal morbidity, and contribute to long-term neurocognitive deficits, pulmonary dysfunction and ophthalmologic disorders. In the past several decades, major progress has been made in improving the survival of extremely premature newborns, mostly attributable to timely access to effective interventions that ameliorate prematurity-associated mortality and morbidity such as antenatal administration of corticosteroids and exogenous surfactant therapy, rather than preventing preterm births. However, the societal and healthcare costs to care for survivors with severe morbidity and neurological handicaps remain substantial. Future research should concentrate on the ways to reduce long-term health sequelae and developmental handicaps among survivors of infants born preterm, as well as elucidating the mechanisms and aetiology of preterm births.

Mechanisms of abruption-induced premature rupture of the fetal membranes: Thrombin enhanced decidual matrix metalloproteinase-3 (stromelysin-1) expression

OBJECTIVE

The aim of the study was to evaluate thrombin and progestin effects on matrix metalloproteinase-3 expression in term decidual cells as a mechanism of abruption-related preterm delivery.

STUDY DESIGN

Decidual cells were isolated by standard techniques, purified to homogeneity, grown to confluence, and passaged. Cultures were primed with 10 (-8) M estradiol or estradiol plus 10 (-7) progestin and then incubated in a defined medium with corresponding steroid(s) plus or minus thrombin or the protease-activated thrombin receptor-1 agonist for 24 hours. Secreted matrix metalloproteinase-3 levels were assessed by enzyme-linked immunosorbent assay, and immunoblotting and messenger RNA levels were measured by Northern blotting and quantitative reverse transcription-polymerase chain reaction.

RESULTS

Immunoreactive matrix metalloproteinase-3 levels were inhibited 66% by estradiol plus progestin versus estradiol ( P < .05). Thrombin elicited a dose-dependent reversal in this progestin inhibition, producing a 2.5-fold increase at 2.5 U/mL ( P < .05) that attained 33% of matrix metalloproteinase-3 levels in parallel incubations with estradiol plus thrombin. Protease-activated thrombin receptor-1 agonist mimicked 60% of thrombin-enhanced matrix metalloproteinase-3 output. Immunoblotting validated the enzyme-linked immunosorbent assay results. Northern blotting and quantitative reverse transcription-polymerase chain reaction demonstrated corresponding effects on steady-state messenger RNA levels.

CONCLUSION

Abruption-generated thrombin promotes preterm delivery by mediating fetal membrane extracellular matrix degradation via enhanced decidual cell matrix metalloproteinase-3 expression, whereas progesterone blunts this thrombin-induced effect.

Animal models of preterm birth

Preterm birth continues to pose a significant clinical dilemma and contributes to both acute and long-term neonatal morbidity. Despite efforts, the incidence of preterm birth has not decreased, partly because of our lack of understanding of the mechanisms that trigger parturition. Animal models are essential research tools for investigating the pathways that promote preterm parturition and for testing therapeutic interventions. Growing evidence correlates infection or inflammation with preterm birth. Consequently, many investigators have created animal models that reflect these findings. Current models of preterm parturition include diverse species, varying means of inducing an inflammatory or infectious state, and different routes of administration. Although each of these models can advance our knowledge, it is important to understand their advantages, disadvantages and unique characteristics. An understanding of such models will hopefully promote continued research that will ultimately lead to a decrease in preterm birth and an improvement in neonatal outcome.

Current medical therapy in the prevention and treatment of preterm labour

The prevention of preterm birth should be one of the major aims of antenatal care. Unfortunately, identification of women who will subsequently deliver preterm is imprecise. Prevention is also difficult. Surgical prevention with cerclage may help a proportion of women. Medical prevention is currently limited to the identification and treatment of bacterial vaginosis, although recent studies have suggested that progesterone prophylaxis may be helpful in some women. Confirmation of efficacy and safety is required before progesterone is introduced as long-term prophylaxis for all women at high risk. The optimal medical treatment (rather than prevention) of threatened preterm labour is controversial. Tocolysis is generally accepted to improve neonatal outcome although this has never been convincingly demonstrated in appropriate trials. Antibiotics confer benefit in the presence of ruptured membranes but are not indicated in uncomplicated preterm labour. In future, it may be possible to identify a subgroup of women in preterm labour with intact membranes who will benefit from tocolysis. The choice of first-line tocolytic therapy is currently debated but atosiban or nifedipine are suggested in current UK guidelines. A direct comparison of these drugs is required in a clinical trial. Although indirect comparisons have been made, these are difficult to interpret due to methodological differences. Each of these drugs have their advocates. Nifedipine has been reported to delay delivery and improve outcome but there are inconsistencies in the clinical trials. Atosiban is also reported to delay delivery and is well tolerated but improved neonatal outcome may have been hidden in clinical trials due to the requirement for rescue tocolysis.

Repeat Measurement of Cervical Length After Successful Tocolysis

OBJECTIVE

To measure the ultrasonographic cervical length in undelivered women after successful tocolysis for preterm labor, and to determine whether this could improve the predictive value of cervical length measured before initiation of tocolysis on the risk of preterm delivery.

METHODS

This was a prospective study of patients admitted and treated for uterine contractions at 24(+0) to 33(+6) weeks of gestation with a cervical length of 26 mm or less by transvaginal ultrasonography on admission. Intravenous tocolysis was stopped when delivery was delayed by 48 hours, and cervical length was remeasured before discharge. The primary outcome was preterm delivery, defined by a delivery before 37 weeks. Predictive analysis was based on logistic models, with estimated odds ratios and 95% confidence interval.

RESULTS

One hundred and nine patients were included in the study. The median (first, third quartile) cervical length on admission was 18 (13, 22) mm. The median (first, third quartile) variation in cervical length after tocolysis was stopped was 3 (0, 8) mm, and ranged from -13 to 26 mm. The median (first, third quartile) time interval from tocolysis to delivery was 53.0 (35.0, 70.0) days, with 45 (41.3%) patients delivered before 37 weeks. After adjustment for cervical length before admission and parity and gestational age on admission, the assessment of the variation in cervical length after successful tocolysis did not improve the predictive value of transvaginal sonography for the risk of preterm delivery (odds ratio 0.97; 95% confidence interval 0.90-1.03; P = .27).

CONCLUSION

To repeat ultrasonographic cervical length measurement after successful tocolysis for preterm labor is useless.

Thromboprophylaxis and pregnancy: two randomized controlled pilot trials that used low-molecular-weight heparin

OBJECTIVE

The purpose of this study was to conduct pilot studies for large randomized controlled trials to compare low-molecular-weight heparin with placebo for antenatal thromboprophylaxis (trial 1), and for thromboprophylaxis after cesarean delivery (trial 2).

STUDY DESIGN

Multicenter randomized controlled trials (trial 1, 23 units; trial 2, 8 units) were conducted. Pregnant women at increased risk for thromboembolic disease were eligible for trial 1; women who underwent cesarean delivery were eligible for trial 2. The interventions were once daily injections of low-molecular-weight heparin or placebo. Primary outcomes were as follows: trial 1, confirmed symptomatic thromboembolic events and symptomatic osteoporotic fractures; trial 2, confirmed symptomatic thromboembolic events and wound complications.

RESULTS

Sixteen women were recruited for trial 1; 1 woman in the placebo group had a symptomatic thromboembolic event. One hundred forty-one women were recruited for trial 2; 1 woman in the low molecular weight heparin group had a symptomatic thromboembolic event.

CONCLUSION

Poor recruitment indicates that large-scale trials using these designs would be difficult. Collection of data on the number of women that are eligible and the reasons for nonrecruitment in future trials of these interventions would allow a better understanding of the reasons for poor recruitment.

Maternal/newborn GSTT1 null genotype contributes to risk of preterm, low birthweight infants

OBJECTIVES

Maternal cigarette smoke exposure during pregnancy has been identified as a risk factor for prematurity and low birthweight. However, little is known about genetic susceptibility and possible interactions with cigarette smoking which may increase risk of these events.

METHODS

Maternal peripheral and umbilical cord blood samples from 955 mother/newborn pairs were genotyped for a panel of phase I/II metabolic enzymes responsible for the metabolism of tobacco related mutagens and carcinogens in order to evaluate the association with premature birth.

RESULTS

As reported previously, maternal cigarette smoking during the last trimester was significantly associated with premature birth. In addition, maternal glutathione S-transferase T1 (GSTT1) null genotype also increased risk of premature birth. Risk was further elevated among subjects with the combination of maternal and newborn GSTT1 null genotype with or without maternal cigarette smoke.

CONCLUSIONS

These observations suggest that women and/or newborns with the GSTT1 null genotype who are exposed to cigarette smoke during pregnancy are at elevated risk for premature delivery. The ability to identify high-risk women by genotyping has potential for reducing the frequency of premature births, a major public health concern.

Progesterone and preterm: seventy years of "déjà vu" or "still to be seen"?

Progestogens for the prevention of preterm birth have a long history. In 2003, two widely publicized double-blind trials, one of daily vaginal progesterone suppositories and the other of weekly intramuscular injections of 17alpha-hydroxyprogesterone, claimed that the treatments effectively reduce the incidence of preterm birth in women at risk of spontaneous preterm labor. Critical analysis of the reports provides no convincing evidence that either one of these treatments is worth pursuing outside the context of controlled research to determine, first, whether and, second, how the treatments might work.

N-glycans of human amniotic fluid transferrin stimulate progesterone production in human first trimester trophoblast cells in vitro

AIMS

During pregnancy, the placenta produces a variety of steroid hormones and proteins. Several of these substances have been shown to exert immunomodulatory effects. Progesterone is thought to mediate some of these effects by regulating uterine responsiveness. The aim of this study was to clarify the effect of amniotic fluid transferrin and its N-glycans on the release of progesterone by first trimester trophoblast cells in vitro.

METHODS

Cytotrophoblast cells were prepared from human first trimester placentae by trypsin-DNAse dispersion of villous tissue followed by a percoll gradient centrifugation and depletion of CD45 positive cells by magnetic cell sorting. Trophoblasts were incubated with varying concentrations (50-300 microg/ml) of transferrin from human amniotic fluid and serum as well as with N-glycans obtained from amniotic fluid transferrin. Culture supernatants were assayed for progesterone by enzyme-immunometric methods.

RESULTS

The release of progesterone increased in amniotic fluid transferrin- and N-glycan-treated trophoblast cell cultures compared to untreated trophoblast cells. There was no stimulating effect of serum transferrin on the progesterone production of trophoblast cells.

CONCLUSIONS

The results suggest that amnion-transferrin and especially its N-glycans modulate the endocrine function of trophoblasts in culture by up regulating progesterone secretion.

Human amniotic fluid glycoproteins expressing sialyl Lewis carbohydrate antigens stimulate progesterone production in human trophoblasts in vitro

BACKGROUND

Progesterone is thought to mediate immune modulator effects by regulating uterine responsiveness. The aim of the study was to clarify the effect of transferrin and glycodelin A (former name PP14) as sialyl Lewis X-expressing glycoproteins on the release of progesterone by trophoblast cells in vitro.

METHODS

Cytotrophoblast cells were prepared from human term placentas by standard dispersion of villous tissue followed by a Percoll gradient centrifugation step. Trophoblasts were incubated with varying concentrations (50-300 microg/ml) of human amniotic fluid- and serum-transferrin as well as with glycodelin A. Culture supernatants were assayed for progesterone, human chorionic gonadotropin (hCG) and cortisol by enzyme immunometric methods.

RESULTS

The release of progesterone is increased in amniotic fluid transferrin- and glycodelin A-treated trophoblast cell cultures compared to untreated trophoblast cells. There is no relation between transferrin and the hCG or cortisol production of trophoblast cells.

CONCLUSION

The results suggest that sialyl Lewis carbohydrate antigen-expressing amniotic fluid glycoproteins modulate the endocrine function of trophoblasts in culture by upregulating progesterone production.

Reducing the risk for preterm birth: evidence and implications for neonatal nurses

The incidence of preterm birth has been slowly rising despite advances in obstetric health care. Neonatal nurses have ongoing contact with women who have had a preterm birth and, thus, who are at high risk to have another preterm birth. This article discusses current evidence about reducing risk for preterm birth. Although preterm birth cannot always be prevented, preconception care can help identify and modify maternal risk and promote optimal health before conception. Quality prenatal care, as defined by the Institute of Medicine, consists of continuing risk assessment, health promotion, and interventions to modify medical and psychosocial risk. When these 3 components are consistently applied, they may confer some protection against preterm birth. Women at highest risk for preterm birth need to seek prenatal care from an expert in maternal-fetal medicine. Women also need to learn about the common, subtle signs of preterm labor so they can recognize symptoms and quickly seek treatment. Neonatal nurses can provide critical information and anticipatory guidance to women at risk for preterm birth so they can make sound decisions about future pregnancies.

Prediction of preterm delivery in twin pregnancy: a prospective, observational study of cervical length and fetal fibronectin testing

OBJECTIVE

To evaluate prospectively cervical length measurements and fetal fibronectin detection as predictors of spontaneous preterm delivery in an unselected population of twin pregnancies.

METHODS

Transvaginal ultrasound assessments of cervical length were performed serially at 18, 24, 28 and 32 weeks' gestation. Receiver-operating characteristic curves were generated at each time point to determine the optimal cut-off for cervical length and rate of change in cervical length in the prediction of preterm delivery (< 35 weeks). A bedside assay for the detection of fetal fibronectin in the maternal vaginal secretions was performed prior to cervical length measurements from 24 weeks. Likelihood ratios (LRs) were used to assess the performance of each test.

RESULTS

The spontaneous preterm delivery rate was 16.5% in 91 studied twin pregnancies. A cervical length </= 25 mm at 18 weeks (LR+ 9.7, sensitivity 14.3%) and </= 22 mm at 24 weeks (LR+ 9.6, sensitivity 28.6%) were the best predictors of preterm delivery. A shortening of cervical length >/= 2.5 mm per week between 18 and 28 weeks' gestation also predicted preterm delivery (LR+ 10.8, sensitivity 16.7%). There was no relationship between the detection of fetal fibronectin and preterm delivery.

CONCLUSIONS

This study confirms the value of transvaginal ultrasound assessment of cervical length as a predictor of preterm delivery in twin pregnancies. However, the poor sensitivity of this test makes it unsuitable as a single predictor of preterm delivery. Fetal fibronectin testing does not identify twin pregnancies destined to deliver prematurely.

End-tidal breath carbon monoxide measurements are lower in pregnant women with uterine contractions

OBJECTIVE

To compare the levels of end-tidal carbon monoxide (ETCOc) among women with and without uterine contractions in term and preterm pregnancies.

STUDY DESIGN

In all, 55 nonsmoking healthy pregnant women were enrolled. ETCOc levels were compared among women with contractions (10 preterm and 13 term) and 32 women without contractions (34-41 weeks gestation).

RESULTS

Maternal age, gravidity and parity were similar among study and control groups. ETCOc levels were significantly lower among women that had uterine contractions (0.99+/-0.38 parts per million (ppm) and 1.15+/-0.34 p.p.m. respectively), compared to women with no contractions (1.70+/-0.52 p.p.m., P<0.002). However, there was no significant difference in the ETCOc levels between women with preterm or term contractions (P=0.48).

CONCLUSIONS

Low levels of ETCOc are associated with preterm and term uterine contractions.

Regulation of the human relaxin genes H1 and H2 by steroid hormones

Relaxin, a peptide hormone important to the outcome of human pregnancy is expressed in a tissue specific manner as two genes known as relaxins H1 and H2, in addition to a third human relaxin H3, expressed primarily in the brain. The H1 and H2 genes are highly homologous, differentially expressed in reproductive tissues and appear to activate the same receptor, but their regulation is poorly understood. Based upon the known physiology of these hormones and the response elements in their 5'- and 3'-flanking regions, the possibility that progesterone and/or the glucocorticoids might influence their differential expression was therefore investigated. The changes in the mRNA levels of the relaxin genes in response to either medroxyprogesterone acetate (MPA) or dexamethasone (Dex) were analyzed by RT-PCR using a choriocarcinoma cell line (JAR) as a model system, because the expression of these genes in any primary human cell type is too low for such a study. The addition of 0.5 microM MPA to JAR cells, significantly upregulated the mRNA of only the relaxin H2, while the addition of 0.5 microM Dex significantly upregulated the mRNAs for both the relaxins, after 6h of treatment. Promoter assays indicated an early activation of transcription (1 h), which by 6 h had decreased. Progesterone and/or glucocorticoids could exert their effects via the GRE motif found on the 5'-flanking region of the relaxin genes. The H1-GRE differs from the H2-GRE by a single nucleotide, which may affect H1-GRE binding to the progesterone receptor (PR) but not the glucocorticoid receptor (GR). The antiprogestin RU486 inhibited the binding of the GR to both H1-GRE and H2-GRE, while it enhanced the binding of the PR to these GREs. As determined by gel shift assays, this GRE motif could bind to both the PR and GR and was therefore considered to be functional. Thus, both progesterone and glucocorticoids are capable of differentially regulating the expression of the two human relaxin genes in a model system.

Medroxyprogesterone acetate, but not progesterone, protects against inflammation-induced parturition and intrauterine fetal demise

OBJECTIVE

This study was undertaken to determine whether progestational agents can prevent inflammation-induced preterm parturition and fetal demise.

STUDY DESIGN

The activation of contractile and inflammatory pathways in response to localized intrauterine inflammation was investigated by using quantitative polymerase chain reaction (PCR). Serum progesterone (P4) levels and alterations in progesterone receptor-B (PR-B) were determined with radioimmunoassay and quantitative PCR, respectively. With our in vivo model of intrauterine inflammation, animals were randomly assigned to pretreatment with P4 or medroxyprogesterone acetate (MPA) before intrauterine lipopolysaccharide (LPS). Animals were observed for preterm delivery. The number of live pups 48 hours after intrauterine LPS was recorded for each treatment group. The ability of MPA to alter signal transduction pathways leading to preterm parturition were investigated by quantitative PCR and histochemical studies.

RESULTS

Intrauterine inflammation is associated with decreased serum progesterone levels and decreased transcription of PR-B. Preterm delivery rates were 100% for LPS alone, 63% for LPS+P4, and 0% for LPS+MPA. No live pups remained at 48 hours in the LPS or LPS+P4 groups. Pretreatment with MPA significantly preserved fetal viability. MPA suppressed activation of contraction-associated genes and inflammatory mediators and prevented cervical ripening in response to intrauterine inflammation.

CONCLUSION

MPA, with its progestational and anti-inflammatory properties, prevented inflammation-induced preterm parturition and significantly preserved fetal viability.

Immunology of term and preterm labor

During pregnancy there is an alteration in maternal immunity within the uterus where innate, proinflammatory immune responses are tightly regulated to prevent immunological rejection of the fetal allograft. Disruption of the delicate balance of cytokines by bacteria or other factors increases the production of proinflammatory cytokines at the maternal-fetal interface and activates the parturition mechanism prematurely. Despite years of searching, there is still no broadly effective strategy for preventing preterm labor and most therapies are directed at inhibiting myometrial contractions and improving neonatal outcome. Recent studies with progestins and interleukin-10 (IL-10), however, are showing promise in randomized clinical trials and animal studies. Furthermore, the identification of the Toll-like receptors as upstream mediators of inflammation may offer alternative therapeutic targets for preventing this common pregnancy complication.

Preterm Labor and Birth: What Have We Learned in the Past Two Decades?

Preterm births in the United States reached a 20-year high of 11.9% in 2001. Preterm and low-birth-weight births are the end result of multiple pathways. This article examines two decades of multidisciplinary research related to preterm birth from both individual and ecologic perspectives. The difficulties in identifying women who will have preterm birth, risk factors amenable to change in the preconception and prenatal periods, and strategies for intervention are described, along with maternal treatment to improve infant outcomes. Future directions for nursing practice and research are suggested.

Pregnancy in dialysis patients: where do we go from here?

Current guidelines for dialysis in pregnant women have been developed in response to occasional dialysis patients who unexpectedly become pregnant. These include prolonged dialysis times, generally 20 or more hours per week. The increased dialysis time requires careful monitoring of phosphorus and potassium which may be removed in excessive amounts. Target serum bicarbonate for a pregnant woman is 18-20 mEq/L. Patients require increased supplementation of water soluble vitamins particularly folate. Increased doses of erythropoietin are needed to meet the demands for increased red cell production occasioned by pregnancy. Hypertension is the greatest danger to the mother and extreme vigilance is required up to six weeks postpartum. Volume status is difficult to predict and can only be determined by repeated clinical assessment. Only 50% of pregnancies result in a surviving infant and in the best subgroups, no more than 75% of pregnancies are successful. Over 80% of live born infants are premature, often severely premature. The key to improving the outcome of pregnancy in dialysis patients lies in decreasing premature labor and premature rupture of membranes in the late second and early third trimester. To this end, it is important for obstetricians to recognize that the risk of prematurity in pregnant dialysis patients is as higher or higher than in any other group and that any intervention, including such measures as progesterone and oxytocin antagonists, used to prevent premature labor in other groups should be considered in dialysis patients.