Tocolytic treatment for the management of preterm labor: a review of the evidence

Uterodilation effect of unripe fruit extract of Crataegus azarolus var. aronia L. on rat uterine smooth muscles

Crataegus azarolus var. aronia L. (C. aronia) is one of the most important medicinal plants used widely in folk medicine for the prevention of several diseases due to its content of several bioactive compounds like phenolic acid, aromatic amines, proanthocyanidins and flavonoids. This study investigated the uterodilation effect of methanol extract (ME) of C. aronia unripe fruit on the uterine smooth muscle in rats. The mechanism of action underlying the plant's extract was also screened. The unripe fruits were cleaned and extracted in methanol. The extract (1.9-4 mg/ml) was tested on rat uterine relaxation in calcium-free Kreb's solution and potassium chloride-induced uterine contraction. The plant extract was also studied in the presence of antagonists in separate experiments to determine the role of various ion channels and hyperpolarizing agents. The plant extract showed an uterodilation effect on the uterus, in which the ME produced a considerable relaxant effect. The results confirmed that the induced dilation was mediated mainly by the nitric oxide pathway and the activation of potassium channels with a limited role of the prostaglandin pathway and calcium channel activation. This in-vitro study provides the first scientific evidence of the claimed effect of C. aronia on uterine relaxation.

Vaginal Nanoformulations for the Management of Preterm Birth

Preterm birth (PTB) is a leading cause of infant morbidity and mortality in the world. In 2020, 1 in 10 infants were born prematurely in the United States. The World Health Organization estimates that a total of 15 million infants are born prematurely every year. Current therapeutic interventions for PTB have had limited replicable success. Recent advancements in the field of nanomedicine have made it possible to utilize the vaginal administration route to effectively and locally deliver drugs to the female reproductive tract. Additionally, studies using murine models have provided important insights about the cervix as a gatekeeper for pregnancy and parturition. With these recent developments, the field of reproductive biology is on the cusp of a paradigm shift in the context of treating PTB. The present review focuses on the complexities associated with treating the condition and novel therapeutics that have produced promising results in preclinical studies.

Effects of Solvents, Emulsions, Cosolvents, and Complexions on Ex Vivo Mouse Myometrial Contractility

A great need exists to develop tocolytic and uterotonic drugs that combat poor, labor-related maternal and fetal outcomes. A widely utilized method to assess novel compounds for their tocolytic and uterotonic efficacy is the isometric organ bath contractility assay. Unfortunately, water-insoluble compounds can be difficult to test using the physiological, buffer-based, organ bath assay. Common methods for overcoming solubility issues include solvent variation, cosolvency, surfactant or complexion use, and emulsification. However, these options for drug delivery or formulation can impact tissue function. Therefore, the goal of this study was to evaluate the ability of common solvents, surfactants, cosolvents, and emulsions to adequately solubilize compounds in the organ bath assay without affecting mouse myometrial contractility. We found that acetone, acetonitrile, and ethanol had the least effect, while dimethylacetamide, ethyl acetate, and isopropanol displayed the greatest inhibition of myometrial contractility based on area under the contractile curve analyses. The minimum concentration of surfactants, cosolvents, and human serum albumin required to solubilize nifedipine, a current tocolytic drug, resulted in extensive bubbling in the organ bath assay, precluding their use. Finally, we report that an oil-in-water base emulsion containing no drug has no statistical effect beyond the control (water), while the drug emulsion yielded the same potency and efficacy as the freely solubilized drug.

Effects of Bryophyllum pinnatum Administration on Wistar Rat Pregnancy: Biochemical and Histological Aspects

INTRODUCTION

Bryophyllum pinnatum is widely used in folk medicine. It has neuropharmacological, anti-inflammatory, immunomodulatory, antidiabetic, hepatoprotective, and nephroprotective effects, among others. It also acts on uterine contractility. It is prescribed by practitioners of anthroposophic medicine for preterm labor, insomnia, and emotional disorders, and has other potential uses in obstetrics. As all drugs currently used in preterm labor have side effects, new tocolytic agents remain an area of active research.

OBJECTIVE

To evaluate the effect of B. pinnatum mother tincture (MT) on albino rats and their offspring throughout pregnancy from a biochemical and histological standpoint.

METHODS

Longitudinal, prospective, randomized controlled bioassay. This is the second stage of a trial that investigated 60 animals distributed across six equal groups: controls C1 and C2, which received 1 and 25 times the vehicle dose (30% ethanol), B1 and B2 (1- and 25-fold doses of B. pinnatum MT), and B3 and B4 (which received 50- and 100-fold doses of B. pinnatum concentrate). At this stage, blood chemistry parameters (glucose, alanine aminotransferase [ALT], aspartate aminotransferase [AST], creatinine, and blood urea nitrogen) were measured in dams, as well as histological aspects of dam liver, kidney, placenta, and uterine tissue and fetal liver, kidney, heart, and brain.

RESULTS

No differences were found between group B1 (therapeutic dose) and its control C1 in relation to glucose, AST, ALT, and creatinine. Group B2 exhibited lower glucose levels than groups C1, B3, and B4. There was no difference in AST across groups. Groups B3 and B4 exhibited higher ALT levels than groups C1 and B1. Groups B1-B4 exhibited higher urea nitrogen levels than group C1. Creatinine levels were higher in groups B2 and B3 than group C1. On morphological evaluation, fatty infiltration of the liver was observed in the alcoholic vehicle control groups (C1 and C2).

CONCLUSIONS

Daily administration of B. pinnatum at therapeutic doses (group B1) to pregnant albino rats appears to be safe, with reduced glucose at dose B2, elevated ALT at doses B3 and B4, and increased urea at doses B1 to B4 and creatinine at B2 and B3, but never exceeding the normal reference range. It was not associated with histological changes in specimens of the maternal or fetal structures of interest.

Short-Term Outcomes of Atosiban in the Treatment of Preterm Labour at the Sultan Qaboos University Hospital, Muscat, Oman: A tertiary care experience

Objectives

This study aimed to generate baseline evidence regarding the effectiveness of atosiban in delaying delivery by ≥48 hours among pregnant women presenting with threatened preterm labour (TPL). The secondary objective was to assess the relationship between atosiban success and various perinatal factors and neonatal outcomes.

Methods

This retrospective study was conducted between June 2008 and May 2018 at the Sultan Qaboos University Hospital, Muscat, Oman. The medical records of all pregnant women who received atosiban between 24–34 gestational weeks for TPL during this period were reviewed.

Results

A total of 159 women were included in the study. Atosiban was successful in delaying delivery by ≥48 hours in 130 cases (81.8%). Approximately half of the women (50.9%) achieved uterine quiescence in <12 hours. Failure to delay delivery by ≥48 hours was significantly lower among women with normal versus abnormal cervical findings (11.1% versus 25.6%; P = 0.023). Only 9.4% of women experienced minor side-effects. Mean birth weight (2,724.55 versus 1,707.59 g; P <0.001) and Apgar scores at 5 minutes (9.66 versus 8.28; P <0.001) were significantly higher among neonates delivered at ≥48 versus <48 hours post-atosiban, whereas the rate of neonatal respiratory distress syndrome was significantly lower (18.4% versus 81.6%; P <0.001).

Conclusion

Atosiban was highly effective in delaying delivery by ≥48 hours and resulted in few adverse maternal side-effects and neonatal outcomes. To the best of the authors’ knowledge, this is the first study conducted in Oman to evaluate the effectiveness of atosiban in preventing preterm labour.

Justicia flava leaf extract potently relaxes pregnant human myometrial contractility: a lead plant for drug discovery of new tocolytic drugs

NEW FINDINGS

What is the central question of this study? Can Justicia flava leaf extract (JF) inhibit human myometrial contractility as was previously shown in mouse myometrium? What is the main finding and its importance? JF abolished human myometrial contractions and therefore presents as a lead plant in drug discovery studies involving drugs for preterm birth.

ABSTRACT

In the search for new potent therapies for preterm labour, Justicia flava leaf extract (JF) was previously shown to potently inhibit uterine contractility in both pregnant and non-pregnant mouse uterus. This study took the investigation a step further and investigated the activity of JF on pregnant human myometrial contractility. JF potently inhibited human myometrial contractility in a concentration-dependent manner. This pilot study provides evidence that JF should be further investigated as a lead plant in the drug discovery of new uterine relaxants.

Impact of tocolysis-intent magnesium sulfate and beta-adrenergic agonists on perinatal brain damage in infants born between 28-36 weeks' gestation

AIMS

Magnesium sulfate has neuroprotective effects in preterm infants. Whether other antepartum treatments interfere with the neuroprotective actions is not well known. This study aims to explore the impacts of antenatal administration of Magnesium sulfate or beta-2 adrenergic agonists as tocolytic agents on the developing brain in premature infants.

METHODS

This is a retrospective cohort study in four tertiary perinatal centers in Japan. We collected data of pregnant women and infants born between 28 and 36 weeks for tocolytic agents, gestational age, sex, antenatal corticosteroid, fetal growth restriction, pathological chorioamnionitis, low umbilical arterial pH values (<7.1), multiple pregnancy, mode of delivery and institutions after excluding clinical chorioamnionitis, non-reassuring fetal status or major anomalies. Tocolytic agents were categorized into four groups: no-tocolysis, magnesium sulfate, beta-2 adrenergic agonists and the combination of them. We conducted multiple comparisons with multivariate analyses using generalized linear regression models to compare the prevalence of a poor perinatal outcome defined as infant's death, brain damage, particularly cerebral palsy and developmental delay.

RESULTS

Among 1083 infants, 39% were no-tocolysis, 47% were magnesium sulfate, 41% were beta-2 adrenergic agonists and 27% were combination group, including the duplication. The incidence of poor perinatal outcome was decreased by magnesium sulfate (OR 0.27, 95% CI 0.10-0.72), but not changed significantly by beta-2 adrenergic agonists (OR 1.28, 95% CI 0.63-2.59) or the combination group (OR 2.24, 95% CI 0.67-7.54), compared with the no-tocolysis.

CONCLUSION

The combination therapy for tocolysis with beta-2 adrenergic agonists diminished the magnesium sulfate neuroprotective action after adjusting for covariables.

The efficacy of transcutaneous electrical nerve stimulation therapy in pain control after cesarean section delivery associated with uterine contractions and abdominal incision

Objectives

This study aims to investigate the effects of transcutaneous electrical nerve stimulation (TENS) therapy on the intensity of pain associated with uterine contractions and abdominal incision in patients undergoing cesarean section (C-section) delivery.

Patients and methods

This single-blind, prospective, randomized-controlled study included a total of 90 female patients (mean age 30.5 years; range, 25 to 36 years) who had a scheduled C-section delivery between November 2017 and April 2018. Forty-five postpartum patients were randomly assigned into the treatment group (Group 1) and TENS electrodes were placed below and above the abdominal incision. The control group (n=45) consisted of 45 patients who had a scheduled C-section (Group 2) (n=45) and received routine follow-up care. The Visual Numeric Scale (VNS) scores were obtained separately for abdominal, low back, and groin pain at baseline (within 1 h after C-section before the TENS replacement), at postpartum 2, 6, 24, and 48 h. In addition to instant scoring, the percentages of change in pain scores from baseline were also calculated for each time points.

Results

Data of a total of 87 patients were analyzed. No statistically significant difference was found in the baseline VNS scores measured in any body regions between the groups (p>0.05). However, there was a statistically significant difference in the instant VNS scores for abdominal pain at 2, 6, 24, and 48 h in favor of Group 1 (p<0.05). No significant differences were found in the instant VNS scores for low back and groin pain (p>0.05). The comparison of changes in pain scores from baseline (% change) over time between the groups revealed a statistically significant difference in favor of Group 1 in all VNS scores for abdominal, low back, and groin pain at 2, 6, 24, and 48 h (p<0.05).

Conclusion

Our study results suggest that TENS is an effective and safe non-invasive, non-pharmacological treatment modality. It may be preferred as an alternative method in pain control in postpartum women after C-section delivery.

Gynecologic cancer in pregnancy

Cancer complicates 1 in 1000 pregnancies. Multidisciplinary consensus comprised of Gynecologic Oncology, Pathology, Neonatology, Radiology, Anesthesiology, Maternal Fetal Medicine, and Social Work should be convened. Pregnancy provides an opportunity for cervical cancer screening, with deliberate delays in treatment permissible for early stage carcinoma. Vaginal delivery is contraindicated in the presence of gross lesion(s) and radical hysterectomy with lymphadenectomy at cesarean delivery is recommended. Women with locally advanced and metastatic/recurrent disease should commence treatment at diagnosis with chemoradiation and systemic therapy, respectively; neoadjuvant chemotherapy to permit gestational advancement may be considered in select cases. Most adnexal masses are benign and resolve by the second trimester. Persistent, asymptomatic, benign-appearing masses can be managed conservatively; surgery, if indicated, is best deferred to 15-20 weeks, with laparoscopy preferable over laparotomy whenever possible. Benign and malignant germ cell tumors and borderline tumors are occasionally encountered, with unilateral adnexectomy and preservation of the uterus and contralateral ovary being the rule. Epithelial ovarian cancer is exceedingly rare. Ultrasonography and magnetic resonance imaging lack ionizing radiation and can be employed to evaluate disease extent. Tumor markers, including CA-125, AFP, LDH, inhibin-B, and even CEA and ßhCG may be informative. If required, chemotherapy can be administered following organogenesis during the second and third trimesters. Because platinum and other anti-neoplastic agents cross the placenta, chemotherapy should be withheld after 34 weeks to avoid neonatal myelosuppression. Bevacizumab, immune checkpoint inhibitors, and PARP inhibitors should be avoided throughout pregnancy. Although antenatal glucocorticoids to facilitate fetal pulmonary maturation and amniotic fluid index assessment can be considered, there is no demonstrable benefit of tocolytics, antepartum fetal heart rate monitoring, and/or amniocentesis. Endometrial, vulvar, and vaginal cancer in pregnancy are curiosities, although leiomyosarcoma and the dreaded twin fetus/hydatidiform mole have been reported. For gynecologic malignancies, pregnancy does not impart aggressive clinical behavior and/or worse prognosis.

Clinical management of the pregnant patient undergoing non-obstetric surgery: Review of guidelines

The management principles of non-obstetric surgery during pregnancy are important concepts for all health care providers to be cognizant of. The goals of non-obstetric surgery are to ensure maternal safety, maintain the pregnancy, and ensure fetal well-being. In this regard, organogenesis occurs roughly between days 7-57 and thus, certain medications have a higher incidence of fetal teratogenicity in this first trimester. Some examples of common surgeries performed urgently or emergently include appendectomies, ovarian detorsions, bowel obstruction, trauma, and cholecystectomies. The choice of anesthetic technique and the selection of appropriate anesthetic drugs should be guided by indication for surgery, the nature of the surgery, and the site of the surgical procedure. Many of the concerns for any patients undergoing urgent or emergent surgery must be considered by anesthesia providers along with steps to ensure the fetus has the best outcome.

Pharmacology for Preterm Labor

Preterm birth occurs with 10% of deliveries and yet accounts for more than 85% of perinatal morbidity and mortality. Management of preterm labor prior to delivery includes a multipronged pharmacologic approach targeting utilization of reproductive hormones for continuation of pregnancy, advancement of fetal lung maturity, and the decrease of uterine contractility (tocolysis). This article will review and compare guidelines on pharmacologic management of preterm labor as recommended by the American College of Obstetricians and Gynecologists and the European Association of Perinatal Medicine. The classifications of drugs discussed include exogenous progesterone, corticosteroids, and tocolytics (β-adrenergic agonists, magnesium sulfate, calcium channel blockers, prostaglandin inhibitors, nitrates, and oxytocin receptor blockers). For each of these drug classes, the following information will be presented: mechanism of action, maternal/fetal side effects, and nursing implications.

Tocolysis and the risk of nonreassuring fetal status among pregnant women in labor: Findings from a population-based retrospective cohort study

The purpose of this study was to evaluate the association between tocolysis for preterm uterine contraction and the risk of nonreassuring fetal status.This was a retrospective cohort study using data from the Taiwan National Health Insurance Research Database. Pregnant women were enrolled if they delivered a baby during January 1, 2003 to December 31, 2011. The occurrence of the nonreassuring fetal status was compared between pregnant women with and without tocolytic treatment for preterm uterine contraction. Multivariable logistic regression models with adjusted cofounders were used to evaluate the association between tocolysis and the risk of nonreassuring fetal status.Of 24,133 pregnant women, 1115 (4.6%) received tocolytic treatment during pregnancy. After adjusting for covariates, pregnant women receiving tocolysis more than one time during pregnancy were found to have significantly higher risk of the nonreassuring fetal status when compared with pregnant women who did not receive tocolysis for uterine contraction (Odds Ratio = 2.70, 95% Confidence Interval: 1.13-6.49).Pregnant women with more frequent tocolysis for preterm uterine contraction during pregnancy had an increased risk of nonreassuring fetal status. Close evaluation of dose and duration of tocolytic treatment is necessary for pregnant women with preterm uterine contraction.

Tocolytic activity assessment of the methanol leaf extract of Justicia flava Vahl (Acanthaceae) on mouse myometrial contractility and preliminary mass spectrometric determination of secondary metabolites

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Justicia flava are traditionally used in the South of Nigeria to prevent preterm births.

AIM OF THE STUDY

In this study, the activity of the methanol leaf extract of J. flava (JF) was investigated on uterine contractility in non-pregnant and pregnant isolated mouse tissues.

MATERIAL AND METHODS

The effects on spontaneous, oxytocin, and KCl-induced contractions were determined. The effects in calcium-free media were also determined. Possible mechanisms of activity were investigated using receptor and channel modulators. Mass spectrometric analysis was additionally performed on the leaf extract to identify secondary metabolites.

RESULTS

JF was observed to inhibit spontaneous, oxytocin and high KCl-induced uterine contractility. JF also inhibited contractions in Ca²⁺-free media. JF was found to exert its inhibitory effect via interaction with inositol triphosphate and ryanodine receptors and also through modulation of K⁺- channels. Lignans and alkaloids were identified with the lignans being the most abundant in JF.

CONCLUSION

JF has been shown to potently inhibit uterine contractions in non-pregnant and pregnant isolated mouse uterus. The inhibitory activity of JF has been shown to occur via blockade of extracellular and intracellular calcium entry and these effects may be due to the lignans identified in - JF. JF has therefore been shown in this study to be a lead plant in the discovery of new drugs with uterine inhibitory activity.

Effect of Ketoprofen and ATB-352 on the Immature Human Intestine: Identification of Responders and Non-responders

BACKGROUND AND OBJECTIVE

The use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with a broad spectrum of life-threatening adverse effects on the immature gastrointestinal tract. NSAID derivatives exploiting the beneficial effects of biologically active gases, such as hydrogen sulfide (H2S), have been developed. Herein, we determined the effects of ketoprofen and ATB-352, a H2S-releasing ketoprofen derivative, on selected metabolic pathways previously identified to be significantly altered by indomethacin in the human immature intestine.

METHODS

Ketoprofen and ATB-352 were tested on human mid-gestation small intestinal explants maintained in a serum-free organ culture system for 48 hours. The expression levels of the representative genes involved in selected metabolic pathways were measured by real-time PCR after a treatment of 48 hours.

RESULTS

Tested at a concentration that allows more than 80% inhibition of PGE2 production, ketoprofen was found to be less damaging than indomethacin at an equivalent dosage. However, based on the inducibility of cyclooxygenase-2 transcript expression, we were able to discriminate between responder individuals in which the deleterious effects observed with indomethacin were attenuated, and non-responder specimens in which the effects were similar to those observed with indomethacin. ATB-352 did not induce significant changes compared to ketoprofen on these metabolic pathways.

CONCLUSIONS

These results show less damaging effects of ketoprofen compared to indomethacin on the immature intestine and indicate that the intestinal response to this NSAID significantly varies between individuals. However, the results did not allow us to demonstrate a specific beneficial effect of H2S release in organ culture.

The Pregnant Trauma Patient

Trauma is the leading non-obstetric cause of maternal death. Optimal management of the pregnant trauma patient requires a multidisciplinary approach. The anaesthetist and critical care physician play a pivotal role in the entire continuum of fetomaternal care, from initial assessment, resuscitation and intraoperative management, to postoperative care that often involves critical care support and patient transfer. Primary goals are aggressive resuscitation of the mother and maintenance of uteroplacental perfusion and fetal oxygenation by the avoidance of hypoxia, hypotension, hypocapnia, acidosis and hypothermia. Recognizing and understanding the mechanisms of injury, the factors that may predict fetal outcome, and the pathophysiological changes that can result from trauma, will allow early identification and treatment of fetomaternal injury. This in turn should improve morbidity and mortality. A framework for the acute care of the pregnant trauma patient is presented.

Oxytocin Receptor Antagonist (Atosiban) in the Threat of Preterm Birth: Does It Have Any Effect on Breastfeeding in the Term Newborn?

AIM

Oxytocin is a hormone involved in the mechanism of breastfeeding, uterine contractions, and social relationships. Atosiban (competitive oxytocin antagonist) is one of the most commonly used tocolytics for the threat of preterm labor in Europe. The aim of this study is to determinate if the administration of atosiban has any influence in the type of feeding in the term newborn at discharge. The secondary objective is to verify its effectiveness for the prevention of preterm delivery and in the possibility of applying treatment to complete lung maturation.

MATERIALS AND METHODS

Retrospective cohort study carried out in a tertiary University Hospital distinguished by WHO-UNICEF as a Baby-Friendly Hospital Initiative. The analysis included 264 women exposed to atosiban during a period of 4 years. One hundred met inclusion criteria. Unexposed infants born right after and before the exposed ones were selected as the not exposed subgroup (n = 200).

RESULTS

Among women treated with atosiban, 82% maintained exclusively breastfed (EBF), 8% had mixed breastfeeding, and 10% had formula feeding at discharge. In the nonexposed group, 82% maintained EBF, 9.5% had mixed breastfeeding, and 8.5% had formula feeding at discharge (p = 0.84). 97.5% of pregnant women treated with atosiban received corticosteroid for lung maturation, and 49.5% completed gestation with term newborns.

CONCLUSION

There were no significant differences in the type of feeding at discharge between the atosiban group and the nonexposed group. In most cases, the administration of tocolytic therapy allowed to complete lung maturation.

Ante-, peri- and postnatal factors associated with intraventricular hemorrhage in very premature infants

BACKGROUND

Intraventricular hemorrhage (IVH) is one of the most serious complications in preterm infants and is associated with neurological sequelae and mortality. Over the past few decades, the rate of IVH has decreased due to improved neonatal intensive care. However, up to 15-25% of very and extremely premature infants (<32 and <28weeks of pregnancy (WOP) respectively) still suffer from IVH.

STUDY PURPOSE

The aim of this study was to perform an updated, multicenter analysis to identify ante-, peri, and postnatal factors other than gestational age/birth weight associated with IVH of any grade in a large cohort of very and extremely premature infants.

METHODS

We performed a retrospective analysis in a prospectively conducted multicenter cohort study between 01/01/1998-31/12/2012 at 5 level 3 perinatal centers. All relevant ante-, peri- and neonatal data were collected and univariate as well as multivariate logistic regression analysis was performed.

RESULTS

765 inborn infants with a gestational age<32 WOP were enrolled into this study (369 (48.2%) female; 396 (51.8%) male). Birth weight ranged from 315g to 2200g (mean 1149.7g, SD 371.9g); 279 (36.5%) were born ≤27+6 WOP and 486 (63.5%)≥28+0 WOP. IVH was seen in 177 (23.1%) patients. Multivariate analysis revealed that in addition to higher gestational age (OR 0.7, CI [0.6-0.8]), antenatal steroid treatment (OR 0.3, CI [0.2-0.6]) and caesarian section without uterine contraction (OR 0.6, CI [0.4-0.9]) were associated with a lower rate of IVH while RDS (OR 5.6, CI [1.3-24.2]), pneumothorax (OR 2.8, CI [1.4-5.5]) and use of catecholamines (OR 2.7, CI [1.7-4.5]) were associated with an increased risk of IVH. After exclusion of gestational age and birth weight from multivariate analysis, early onset sepsis (OR 1.6, CI [1.01-2.7]) and patent ductus arteriosus (OR 1.9, CI [1.1-3.1]) were associated with a higher rate of IVH. In addition, univariate analysis revealed that Apgar scores at 5min (p<0.001), BDP/ROP/NEC (p<0.001), mechanical ventilation (p<0.001) and inhalative nitric oxide (p<0.001) were significantly associated with IVH.

CONCLUSIONS

Our comprehensive analysis demonstrated that the occurrence of IVH in very premature infants is significantly associated with ante-, peri- and postnatal factors being either related to the degree of immaturity or indicating a critical clinical course after birth. The analysis reiterates the necessity for a very close cooperation between obstetricians and neonatologists to reduce the incidence of IVH in this susceptible cohort.

ATP-sensitive and maxi potassium channels regulate BRL 37344-induced tocolysis in buffaloes-an in vitro study

Cellular coupling of beta₃-adrenoceptors (β₃-ADR) to potassium channels in myometrium is largely unknown. In vitro study was undertaken to unravel the presence of β₃-adrenergic receptors (ADR) and the role of K⁺-channels in mediating β₃-ADR-induced relaxation in isolated myometrial strips from cyclic non-pregnant water buffaloes. Isometric tension was recorded in isolated myometrial strips using data acquisition system based physiograph. Compared to SR 59230A, BRL 37344 was found to be more potent in inducing β₃-dependent myometrial relaxation which was significantly (p < 0.05) inhibited in the presence of β₃ antagonist, SAR 150640. The immunoreactive protein to β₃-ADR was also detected in membrane fraction of myometrial protein. Further, incubation with BRL 37344 (10 μM) significantly (p < 0.05) increased c-AMP accumulation (37.58 ± 9.52 pmol/mg protein; n = 4) in the myometrial strips compared to basal c-AMP level (16.85 ± 3.87 pmol/mg protein; n = 4). The concentration response curves (CRC) of BRL 37344 were significantly (p < 0.05) shifted towards right in the presence of K_ATP channels specific blocker, glibenclamide (10 μM) and maxi K⁺-channels (BK_Ca) specific blocker, iberiotoxin (100 nM), with decrease in both efficacy and potency as compared to control. However, 4-aminopyridine (4-AP), a specific blocker of the voltage gated K⁺-channels (Kv), failed to alter the CRC of BRL 37344. Existence of immunoreactive protein to Kir6.1, α-subunit of BK_Ca and Kv1.1 channels were also detected in the membrane fraction of myometrial protein. Based on the above findings, it can be concluded that BRL 37344 is a potent stimulator of β₃-adrenoceptors in buffalo myometrium and besides mediating their effect through rise in c-AMP, they are coupled to K_ATP and BK_Ca channels in inducing tocolytic effects.

Progesterone in women with arrested premature labor, a report of a randomised clinical trial and updated meta-analysis

BACKGROUND

Progesterone may be effective in prevention of premature birth in some high risk populations. Women with arrested premature labor are at risk of recurrent labor and maintenance therapy with standard tocolytics has not been successful.

METHODS

Randomized double blinded clinical trial of daily treatment with 200 mg vaginal progesterone in women with arrested premature labor and an updated meta-analysis.

RESULTS

The clinical trial was terminated early after 41 women were enrolled. Vaginal progesterone treatment did not change the median gestational age at delivery: 36+2 weeks versus 36+4 weeks, p = .865 nor increase the mean latency to delivery: 44.5 days versus 46.6 days, p = .841. In the updated meta-analysis, progesterone treatment did reduce delivery <37 weeks gestation and increase latency to delivery, but this treatment effect was not evident in the high quality trials: (OR 1.23, 95% CI 0.91, 1.67) and (-0.95 days, 95% CI -5.54, 3.64) respectively.

CONCLUSION

Progesterone is not effective for preventing preterm birth following arrested preterm labor.

Outcomes of Admissions for Preterm Labor

Objective  This study aims to quantitate the incidence of preterm labor (PTL) admissions and determine the frequency and predictors of preterm delivery (PTD) during these admissions. Study Design  Retrospective cohort of singleton pregnancies within Kaiser Permanente Northern California, 2001 to 2011. PTL admissions were defined as inpatient encounters > 24 hours with an International Classification of Diseases, 9th Revision code for PTL. Results  Total study population was 365,897 with PTL admission rate 11%. PTD occurred in 85% of pregnancies with PTL admission. Delivery occurred within 48 hours of admission in 96% ≥34 weeks, 67% 31 to 33 weeks, and 51.9% <31 weeks. Predictors of delivery during PTL admission included gestational age 34 to 36 weeks (adjusted odds ratio [aOR], 6.90), chorioamnionitis (aOR, 105.58), and preterm rupture of membranes (aOR 19.29). Conclusion  We demonstrate a high rate of PTD per PTL admission in a highly integrated health care system. More work is needed to determine optimal practices for hospitalization and treatment of women diagnosed with PTL.

Cervical pessary for the prevention of preterm birth: is it of any use?

Preterm birth (PTB) represents a heavy burden in modern obstetrics as it is a major cause of perinatal morbidity and mortality. After the introduction of transvaginal sonography (TVS) screening, secondary prevention of PTB has been re-evaluated on the basis of pre-existing cervical length (CL) and meanwhile the cervical pessary has become an object of increasing interest. This device consists of a silicone cone acting mechanically, that can be easily placed or removed, but whose efficacy is still controversial. Therefore, this study aims to review the most recent evidence regarding its efficacy for prevention of PTB, together with the correct position, the evidence regarding the mechanism of action, the exclusion criteria for pessary placement and the reasons for precocious removal. Overall, it is well tolerated and there are no reports on severe associated side effects. Finally, we discuss published data regarding cervical pessary efficacy. Although results are still conflicting, it seems however to be an effective method for preventing PTB, both in singleton and multiple pregnancies, but further evidence is needed.

The Synergic In Vitro Tocolytic Effect of Nifedipine Plus Ritodrine on Human Myometrial Contractility

Many pharmacological agents have been investigated to manage preterm labor; we postulate that a combination of tocolytic drugs may achieve a better effect in the prevention of uterine contractions without dose-dependent adverse effects. The aim of this study was to evaluate the inhibitory effect of dual combinations of tocolytics in vitro. Human myometrium was obtained during elective cesarean sections (term without labor; n = 40). Myometrial strips were placed in organ baths for the measurement of isometric tension. Contractile activity was induced by oxytocin (10^-8 mol/L), then a concentration-response curve to single or dual combinations of tocolytics was started. All studied tocolytics (nifedipine, ritodrine, nitroglycerin, atosiban, and NS-1619), when used alone, significantly inhibited myometrial contractions. When combined, nifedipine plus ritodrine produced a significantly greater inhibition of contractility than each drug alone in the midrange of concentrations. The combination of nifedipine plus nitroglycerin or nifedipine plus atosiban produced a significantly greater inhibition than nitroglycerin or atosiban alone but not greater than nifedipine. The combination of nifedipine plus NS-1619 (Ca⁺²-activated K⁺ [BK_Ca] channel opener) reduced the inhibitory effect of each drug. We concluded that a selected combination of tocolytics (nifedipine plus ritodrine) produced a significantly greater inhibitory effect on contractility than each drug alone at intermediate concentrations. Thus, specific combinations of tocolytics with different intracellular signaling pathways may have a synergic effect constituting a provocative new option for preterm labor treatment.

Preterm birth: An overview of risk factors and obstetrical management

Preterm birth is the leading cause of neonatal mortality and a major public health concern. Risk factors for preterm birth include a history of preterm birth, short cervix, infection, short interpregnancy interval, smoking, and African-American race. The use of progesterone therapy to treat mothers at risk for preterm delivery is becoming more widespread. Tocolytics may not prevent preterm birth but have a role in prolonging pregnancy for administration of medications to benefit the preterm infant. These include antenatal steroids and, if indicated, magnesium sulfate for neuroprotection and intravenous antibiotics for Group B Streptococcus prophylaxis.

Nifedipine versus atosiban for threatened preterm birth (APOSTEL III): a multicentre, randomised controlled trial

BACKGROUND

In women with threatened preterm birth, delay of delivery by 48 h allows antenatal corticosteroids to improve neonatal outcomes. For this reason, tocolytics are often administered for 48 h; however, there is no consensus about which drug results in the best maternal and neonatal outcomes. In the APOSTEL III trial we aimed to compare the effectiveness and safety of the calcium-channel blocker nifedipine and the oxytocin inhibitor atosiban in women with threatened preterm birth.

METHODS

We did this multicentre, randomised controlled trial in ten tertiary and nine teaching hospitals in the Netherlands and Belgium. Women with threatened preterm birth (gestational age 25-34 weeks) were randomly assigned (1:1) to either oral nifedipine or intravenous atosiban for 48 h. An independent data manager used a web-based computerised programme to randomly assign women in permuted block sizes of four, with groups stratified by centre. Clinicians, outcome assessors, and women were not masked to treatment group. The primary outcome was a composite of adverse perinatal outcomes, which included perinatal mortality, bronchopulmonary dysplasia, sepsis, intraventricular haemorrhage, periventricular leukomalacia, and necrotising enterocolitis. Analysis was done in all women and babies with follow-up data. The study is registered at the Dutch Clinical Trial Registry, number NTR2947.

FINDINGS

Between July 6, 2011, and July 7, 2014, we randomly assigned 254 women to nifedipine and 256 to atosiban. Primary outcome data were available for 248 women and 297 babies in the nifedipine group and 255 women and 294 babies in the atosiban group. The primary outcome occurred in 42 babies (14%) in the nifedipine group and in 45 (15%) in the atosiban group (relative risk [RR] 0·91, 95% CI 0·61-1·37). 16 (5%) babies died in the nifedipine group and seven (2%) died in the atosiban group (RR 2·20, 95% CI 0·91-5·33); all deaths were deemed unlikely to be related to the study drug. Maternal adverse events did not differ between groups.

INTERPRETATION

In women with threatened preterm birth, 48 h of tocolysis with nifedipine or atosiban results in similar perinatal outcomes. Future clinical research should focus on large placebo-controlled trials, powered for perinatal outcomes.

FUNDING

ZonMw (the Netherlands Organisation for Health Research and Development).

Tocolysis for Women With Early Spontaneous Preterm Labor and Advanced Cervical Dilation

OBJECTIVE

To characterize tocolytic use and examine perinatal outcomes among women presenting very preterm with spontaneous labor and cervical dilation 4 cm or greater.

METHODS

This was a retrospective cohort study. Data from January 2000 to June 2011 in a single health care system were reviewed. Women with singleton, nonanomalous fetuses and preterm labor with intact membranes between 23 and 32 weeks of gestation who had cervical dilation 4 cm or greater and less than 8 cm at admission were included. Women receiving one or more tocolytics (magnesium sulfate, indomethacin, or nifedipine) were compared with those who did not receive tocolysis. The primary outcome was composite major neonatal morbidity.

RESULTS

Two hundred ninety-seven women were included; 233 (78.5%) received at least one tocolytic. Women receiving tocolysis were slightly less dilated (median 5 compared with 6 cm, P<.001) at presentation and were more likely to receive at least a partial course of corticosteroids (88.4% compared with 56.3%, P<.001). Initial composite severe neonatal morbidity rates were similar (41.6% compared with 43.8%, P=.761) regardless of tocolytic administration. Those receiving tocolysis were significantly more likely to be pregnant at least 48 hours after admission (23.6% compared with 7.8%, P=.005), but a similar proportion delivered within 7 days of admission (94.8% compared with 95.3%, P>.99), and delivery gestational ages were similar (28.9 compared with 29.2 weeks, P=.408). The incidence of chorioamnionitis and postpartum endometritis was similar between groups.

CONCLUSION

The majority of women presenting very preterm with advanced cervical dilation received tocolysis. Although tocolysis administration increased the likelihood of achieving at least 48 hours of latency, initial neonatal outcomes were similar.

LEVEL OF EVIDENCE

II.

Does magnesium sulfate delay the active phase of labor in women with premature rupture of membranes? A randomized controlled trial

OBJECTIVE

Administration of many drugs including magnesium sulfate (MS) has considerable influences on pregnancy outcomes. The present study investigates the effects of MS administration on reaching the active phase of labor in women with premature rupture of membrane (PROM) and subsequent fetal complications.

MATERIALS AND METHODS

A double blind, randomized, placebo-controlled trial was performed among primipara women referred to the PROM center in Tehran, Iran between March 2010 and August 2012. Patients were equally allocated into two groups; the intervention group who received MS (n = 46) and the control (placebo) group (n = 46). Both groups received a corticosteroid, 1g oral azithromycin (oral) and 2 g ampicillin (IV) every 6 hours for 48 hours, followed by amoxicillin (500 mg orally 3 times daily) for an additional 5 days. None of the research staff were aware of the treatment allocation of patients in order for blinding purposes.

RESULTS

Administration of MS in intervention group increases this period 2.7 times compared to the control group. In women whose gestational age was <30 weeks, MS administration increased the active phase of labor up to 77%. Administration of magnesium sulfate reduced the risk of respiratory distress syndrome significantly (p = 0 .002), without producing any adverse pregnancy outcomes.

CONCLUSION

Magnesium sulfate increases delay in reaching the active phase of labor in mothers with PROM, without producing adverse birth outcomes. (Registration ID in IRCT; IRCT2012091810876N1).

Abdominal surgery in pregnancy--an interdisciplinary challenge

BACKGROUND

Abdominal operations are performed during ca. 2% of all pregnancies. They represent an unusual situation not only for the patient, but also for the involved surgeons and anesthesiologists. Appendectomy, followed by cholecystectomy are the two most common types of operation performed during pregnancy. Special questions arise with regard to the peri- and intraoperative management and the optimal surgical approach.

METHOD

This review is based on pertinent articles retrieved by a selective search in the PubMed database.

RESULTS

The question of laparoscopy versus laparotomy during pregnancy has been addressed to date only in case series and a few meta-analyses. Two meta-analyses have shown a significantly higher rate of miscarriage after laparoscopic, compared to open, appendectomy (relative risk [RR] 1.91, 95% confidence interval [CI] 1.31-2.77). The risk of preterm birth is also somewhat higher after laparoscopic appendectomy according to one meta-analysis on this subject (RR 1.44, 95% CI 0.78-1.76), but significantly lower according to another meta-analysis (2.1% vs. 8.1%, p<0.0001). For cholecystectomy, laparoscopy was associated with a lower miscarriage rate than laparotomy (1 in 89 cases, versus 2 in 69 cases), but with a somewhat higher preterm birth rate (6 in 89 cases, versus 2 in 69 cases). Delay or non-performance of surgery in a patient with appendicitis or cholecystitis can lead to additional hospitalizations, a higher miscarriage rate, premature rupture of the membranes, and preterm birth.

CONCLUSION

Laparoscopy in experienced hands is safe even during pregnancy, with the recognized advantages of minimally invasive surgery, yet it carries a higher miscarriage rate than laparotomy, with a comparable preterm birth rate. Before surgery, patients should be thoroughly informed about the operation they are about to undergo and the advantages and disadvantages of the available surgical approaches.

Management of pregnant patients undergoing general surgical procedures

Pregnant patients have a 0.2% to 0.75% chance of developing a medical condition that requires a general surgical intervention during pregnancy. To safely and appropriately care for patients, surgeons must be cognizant of the maternal physiologic changes in pregnancy as well as of the unique risk to both mothers and fetuses of diagnostic modalities, anesthetic care, operative intervention, and postoperative management. Surgeons can be assured that, if these risks are understood and considered, operating during pregnancy, even in the abdomen, can be safely undertaken.

Functional insights into modulation of BKCa channel activity to alter myometrial contractility

The large-conductance voltage- and Ca(2+)-activated K(+) channel (BKCa) is an important regulator of membrane excitability in a wide variety of cells and tissues. In myometrial smooth muscle, activation of BKCa plays essential roles in buffering contractility to maintain uterine quiescence during pregnancy and in the transition to a more contractile state at the onset of labor. Multiple mechanisms of modulation have been described to alter BKCa channel activity, expression, and cellular localization. In the myometrium, BKCa is regulated by alternative splicing, protein targeting to the plasma membrane, compartmentation in membrane microdomains, and posttranslational modifications. In addition, interaction with auxiliary proteins (i.e., β1- and β2-subunits), association with G-protein coupled receptor signaling pathways, such as those activated by adrenergic and oxytocin receptors, and hormonal regulation provide further mechanisms of variable modulation of BKCa channel function in myometrial smooth muscle. Here, we provide an overview of these mechanisms of BKCa channel modulation and provide a context for them in relation to myometrial function.

Nifedipine versus atosiban in the treatment of threatened preterm labour (Assessment of Perinatal Outcome after Specific Tocolysis in Early Labour: APOSTEL III-Trial)

Background

Preterm birth is the most common cause of neonatal morbidity and mortality. Postponing delivery for 48 hours with tocolytics to allow for maternal steroid administration and antenatal transportation to a centre with neonatal intensive care unit facilities is the standard treatment for women with threatening preterm delivery in most centres. However, there is controversy as to which tocolytic agent is the drug of first choice. Previous trials have focused on tocolytic efficacy and side effects, and are probably underpowered to detect clinically meaningfull differences in neonatal outcome. Thus, the current evidence is inconclusive to support a balanced recommendation for clinical practice. This multicenter randomised clinical trial aims to compare nifedipine and atosiban in terms of neonatal outcome, duration of pregnancy and maternal side effects.

Methods/Design

The Apostel III trial is a nationwide multicenter randomised controlled study. Women with threatened preterm labour (gestational age 25 – 34 weeks) defined as at least 3 contractions per 30 minutes, and 1) a cervical length of ≤ 10 mm or 2) a cervical length of 11-30 mm and a positive Fibronectin test or 3) ruptured membranes will be randomly allocated to treatment with nifedipine or atosiban. Primary outcome is a composite measure of severe neonatal morbidity and mortality. Secondary outcomes will be time to delivery, gestational age at delivery, days on ventilation support, neonatal intensive care (NICU) admittance, length admission in neonatal intensive care, total days in hospital until 3 months corrected age, convulsions, apnoea, asphyxia, proven meningitis, pneumothorax, maternal side effects and costs. Furthermore, an economic evaluation of the treatment will be performed. Analysis will be by intention to treat principle. The power calculation is based on an expected 10% difference in the prevalence of adverse neonatal outcome. This implies that 500 women have to be randomised (two sided test, β 0.2 at alpha 0.05).

Discussion

This trial will provide evidence on the optimal drug of choice in acute tocolysis in threatening preterm labour.

Trial registration

Clinical trial registration: NTR2947, date of registration: June 20th 2011.

Progestational agents for treating threatened or established preterm labour

BACKGROUND

Prematurity is not only the leading cause of perinatal morbidity and mortality but is associated with long-term impairment. Studies of various tocolytic agents have shown mixed results with little effect in improving pregnancy duration and insufficient data to confirm a definite beneficial effect on neonatal morbidity or mortality. Progesterone is known to have an inhibitory effect on uterine contractility and is thought to play a key role in the maintenance of pregnancy until term.

OBJECTIVES

To determine if the use of progestational agents is effective as a form of treatment or co-treatment for women with threatened or established preterm labour with intact membranes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2013), CENTRAL (The Cochrane Library 2013, Issue 10), MEDLINE (1966 to August 31 2013) and Embase (1974 to 31 August 2013). We checked the reference lists of all included studies to identify any additional studies and communicated with authors and the pharmaceutical industry.

SELECTION CRITERIA

Randomised controlled trials that compared progestational agents, given either alone or in combination with other tocolytics, with a control group receiving another tocolytic, placebo or no treatment, for the treatment of preterm labour.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trial quality.

MAIN RESULTS

Eight studies were included in this review, involving 563 women, but only seven studies, involving 538 women, contributed data for analyses. There are some data suggesting that the use of progestational agents results in a reduction of preterm deliveries at less than 37 weeks of gestation and an increase in birthweight. The use of a progestational agent may also reduce the frequency of uterine contractions, prolong pregnancy and attenuate the shortening of cervical length. However, the analysis was limited by the relatively small number of available studies. The power of the meta-analysis was also limited by the varying types, dosages and routes of administration of progesterone.

AUTHORS' CONCLUSIONS

There is insufficient evidence to advocate progestational agents as a tocolytic for women presenting with preterm labour.

A novel molecular microbiologic technique for the rapid diagnosis of microbial invasion of the amniotic cavity and intra-amniotic infection in preterm labor with intact membranes

PROBLEM

The diagnosis of microbial invasion of the amniotic cavity (MIAC) has been traditionally performed using traditional cultivation techniques, which require growth of microorganisms in the laboratory. Shortcomings of culture methods include the time required (days) for identification of microorganisms, and that many microbes involved in the genesis of human diseases are difficult to culture. A novel technique combines broad-range real-time polymerase chain reaction with electrospray ionization time-of-flight mass spectrometry (PCR/ESI-MS) to identify and quantify genomic material from bacteria and viruses.

METHOD OF STUDY

AF samples obtained by transabdominal amniocentesis from 142 women with preterm labor and intact membranes (PTL) were analyzed using cultivation techniques (aerobic, anaerobic, and genital mycoplasmas) as well as PCR/ESI-MS. The prevalence and relative magnitude of intra-amniotic inflammation [AF interleukin 6 (IL-6) concentration ≥ 2.6 ng/mL], acute histologic chorioamnionitis, spontaneous preterm delivery, and perinatal mortality were examined.

RESULTS

(i) The prevalence of MIAC in patients with PTL was 7% using standard cultivation techniques and 12% using PCR/ESI-MS; (ii) seven of ten patients with positive AF culture also had positive PCR/ESI-MS [≥17 genome equivalents per PCR reaction well (GE/well)]; (iii) patients with positive PCR/ESI-MS (≥17 GE/well) and negative AF cultures had significantly higher rates of intra-amniotic inflammation and acute histologic chorioamnionitis, a shorter interval to delivery [median (interquartile range-IQR)], and offspring at higher risk of perinatal mortality, than women with both tests negative [90% (9/10) versus 32% (39/122) OR: 5.6; 95% CI: 1.4-22; (P < 0.001); 70% (7/10) versus 35% (39/112); (P = 0.04); 1 (IQR: <1-2) days versus 25 (IQR: 5-51) days; (P = 0.002), respectively]; (iv) there were no significant differences in these outcomes between patients with positive PCR/ESI-MS (≥17 GE/well) who had negative AF cultures and those with positive AF cultures; and (v) PCR/ESI-MS detected genomic material from viruses in two patients (1.4%).

CONCLUSION

(i) Rapid diagnosis of intra-amniotic infection is possible using PCR/ESI-MS; (ii) the combined use of biomarkers of inflammation and PCR/ESI-MS allows for the identification of specific bacteria and viruses in women with preterm labor and intra-amniotic infection; and (iii) this approach may allow for administration of timely and specific interventions to reduce morbidity attributed to infection-induced preterm birth.

Maintenance therapy with calcium channel blockers for preventing preterm birth after threatened preterm labour

BACKGROUND

Calcium channel blocker maintenance therapy is one of the types of tocolytic therapy that may be used after an episode of threatened preterm labour (and usually an initial dose of tocolytic therapy) in an attempt to prevent the onset of further preterm contractions.

OBJECTIVES

To assess the effects of calcium channel blockers as maintenance therapy on preventing preterm birth after threatened preterm labour.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2013) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials of calcium channel blockers used as maintenance therapy to prevent preterm birth after threatened preterm labour, compared with placebo or no treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of included studies.

MAIN RESULTS

We included six trials that enrolled 794 women and their babies and all assessed nifedipine as calcium channel blocker maintenance therapy. The six trials were judged to be at a moderate risk of bias overall. No differences in the incidence of preterm birth (risk ratio (RR) 0.97; 95% confidence interval (CI) 0.87 to 1.09; five trials, 681 women), birth within 48 hours of treatment (RR 0.46; 95% CI 0.07 to 3.00; two trials, 128 women) or neonatal mortality (average RR 0.75; 95% CI 0.05 to 11.76; two trials, 133 infants) were seen when nifedipine maintenance therapy was compared with placebo or no treatment. No stillbirths were reported in the one trial that provided data for this outcome. No trials reported on longer-term follow-up of infants.Women receiving nifedipine maintenance therapy were significantly more likely to have their pregnancy prolonged (mean difference (MD) 5.35 days; 95% CI 0.49 to 10.21; four trials, 275 women); however, no differences between groups were shown for birth at less than 34 weeks' gestation, birth at less than 28 weeks' gestation, birth within seven days of treatment, or gestational age at birth. No significant differences were shown between the nifedipine and control groups for any of the secondary neonatal morbidities reported. Similarly, no significant differences were seen for the outcomes relating to the use of health services, except for in one trial, where infants whose mothers received nifedipine were significantly more likely to have a longer length of hospital stay as compared with infants born to mothers who received a placebo (MD 14.00 days; 95% CI 4.21 to 23.79; 60 infants).

AUTHORS' CONCLUSIONS

Based on the current available evidence, maintenance treatment with a calcium channel blocker after threatened preterm labour does not prevent preterm birth or improve maternal or infant outcomes.

A comparison of three tocolytics for preterm labor: a randomized clinical trial

OBJECTIVE

To compare the efficacy and maternal side effects of nifedipine (N), magnesium sulfate (M), and indomethacin (I) for acute tocolysis.

METHODS

In this single center randomized trial, women in preterm labor 24-32 weeks' gestation received intravenous M, oral N, or I suppositories. The primary outcomes of interest were arrest of preterm labor (>48 h, ≥7 days), gestational age at delivery, and maternal side effects.

RESULTS

Over a 38-month period, 301 women were allocated to receive M (90), N (114), or I (90). Gestational age at delivery (p = 0.551) or arrest of labor >48 h, >7 days were similar between the three groups (p = 0.199, 0.654). Hypotension and tachycardia were more common in N patients compared to women receiving M or I (p = 0.003, 0.009). Patients receiving I had more fetal ductal constriction or oligohydramnios compared to M or N (p = 0.001, 0.020) but, I women were tested more often. There was one case of pulmonary edema in the M group and one with plural effusion in the N group.

CONCLUSION

There were no differences in efficacy or in major maternal safety issues between the three tocolytic agents. Since there is no FDA approved tocolytic to treat preterm labor, clinicians should use the tocolytic that has afforded them the best results with the least maternal/neonatal side effects.

Morbidity and mortality following envenomation by the common night adder (Causus rhombeatus) in three dogs

In South Africa dogs are frequently presented to veterinarians following snakebite. The offending snakes are usually puff adders (Bitis arietans), cobras (Naja spp.) and mambas (Dendroaspis spp.). Night adder (Causus rhombeatus) bites in dogs have not yet been reported in South Africa. This article deals with three cases of dogs bitten by night adders in which extensive tissue damage was noted and one fatality occurred. Night adder bites may be indistinguishable from puff adder bites. Non-specific treatment included addressing the hypovolaemia and swelling. Specific treatment involving immunotherapy using the South African polyvalent antivenom would be ineffective as it does not contain immunoglobulins against night adder venom. Veterinarians should also include night adders as the possible cause of dogs suffering from severe and painful swellings suspected to be due to snakebites.

Expression of selected genes in preterm premature rupture of fetal membranes

OBJECTIVE

To analyse the expression of 15 genes encoding receptors and enzymes associated with the molecular mechanism of the tocolytic drugs atosiban (oxytocin receptor antagonist), nifedipine (calcium channel blocker) and celecoxib (selective cyclo-oxygenase-2 inhibitor) in preterm labor patients with premature rupture of fetal membranes in relation to symptoms of intrauterine infection and preterm labor risk factors.

DESIGN

Experimental molecular study.

SETTING

Tertiary obstetric care center.

SAMPLE

Myometrial samples were obtained during cesarean sections from 35 patients who delivered preterm with unverified symptoms of intrauterine infection, 35 patients who delivered preterm without symptoms of intrauterine infection and 90 women who delivered at term.

METHODS

The Micro Fluidic Profiling Card analytic system was used to evaluate mRNA expression of the genes of interest.

MAIN OUTCOME MEASURES

The relative quantification values for mRNA expression.

RESULTS

The median oxytocin receptor and cyclo-oxygenase-2 mRNA expression in preterm patients with clinical symptoms of intrauterine infection was significantly higher than in preterm patients without symptoms. The median mRNA expression of β(1) , β(3) and β(4) subunits of the L-type calcium channel and prostaglandin E(2) receptor was significantly higher in preterm patients compared with term patients.

CONCLUSIONS

The mRNA expression of hormones, enzymes and their receptors associated with tocolytic actions can differ in various clinical conditions. The expression of these genes is regulated at different levels and can be modified by inflammatory factors, which affect their functions.

Laparoscopic management of pseudocyst of the pancreas in a pregnant patient

Gallstone pancreatitis is a rare problem in pregnant patients. A primigravida with persistent symptoms of abdomen pain, nausea, vomiting, and inability to tolerate oral diet presented at 5 weeks of pregnancy. A laparoscopic cystogastrostomy with cholecystectomy was performed at 13 weeks of pregnancy. There are only 10 case reports in literature of pseudocyst in pregnancy and in none of them ante partum surgical management was done.

Effects and selectivity of CL 316243, beta-3-adrenoceptor agonist, in term-pregnant rat myometrium

BACKGROUND/AIMS

Recent evidence supports a predominant role of β(3)-adrenoceptors at the end of pregnancy in myometrium. This study was designed to characterize the pharmacology of the selective β(3)-adrenoceptor agonist CL 316243 on oxytocin-induced myometrial contractions and the levels of cAMP and cGMP of myometrial strips isolated from term-pregnant rats.

METHODS

Myometrial strips were obtained from term-pregnant Wistar albino rats (n = 10), mounted in organ baths and tested for changes in isometric tension in response to CL 316243 (10(-10)-10(-5) M) on oxytocin-induced myometrial contractions. Effects of CL 316243 on cAMP and cGMP levels in isolated myometrial strips (n = 8) were evaluated by radioimmunoassay kits. We evaluated the effect of increasing concentrations of CL 316243 on myometrial contractions and on contractions of myometrial smooth muscle pretreated with metoprolol, ICI 118.551 and SR 59230A (β(1)-, β(2)-, β(3)-adrenoceptor antagonists, respectively, 10(-6) M).

RESULTS

The inhibition of the amplitude of oxytocin-induced contractions by CL 316243 were antagonized with SR 59230A (10(-6) M), but they were not changed by metoprolol (10(-6) M) or ICI 118.551 (10(-6) M). CL 316243 increased cAMP levels compared to the control group. CL 316243 increased cGMP levels, in the CL 316243 group more than in the control group, but this increase is less significant than cAMP levels.

CONCLUSION

These results demonstrate that the inhibition of rat myometrial contractions with CL 316243 is mediated by β(3)-adrenoceptor subtype and increased cAMP and cGMP levels.

Magnesium sulfate: past, present, and future

First used anecdotally for the control of eclamptic seizures in the early 1900s, magnesium sulfate remains 1 of the most commonly used medications in obstetric practice today. Over the past 95 years, there have been countless research studies investigating the efficacy of magnesium sulfate for the management of eclampsia, preeclampsia, preterm labor, and most recently for prevention of cerebral palsy. The majority of this evidence undeniably supports the use of magnesium sulfate as the drug of choice for the prevention and treatment of eclampsia when evidence of severe disease is present. On the other hand, studies have not shown magnesium sulfate to be comparably more effective than other tocolytics for treating preterm labor, nor is there agreement on whether the evidence supports its use as a neuroprotective agent for prevention of cerebral palsy. The exact mechanism of action of magnesium sulfate remains largely hypothetical, and parenteral use has the potential to cause significant morbidity in high doses. This article reviews magnesium sulfate's remarkable history in obstetric practice and includes a summary of the evidence related to each of the controversies. An initial review of the physiology of magnesium sulfate is essential to understanding pharmacodynamic actions, dosing guidelines, and safety requirements.

Myth: tocolysis for prevention of preterm birth has a major role in modern obstetrics

Tocolytics are widely used to reduce uterine activity in the context of preterm labour. Growing evidence that bacterial colonization of fetal membranes and amniotic fluid triggers an inflammatory response in mother and fetus and leads to preterm labour and long term neurological and respiratory complications in the neonate also raises questions about the desirability of prolonging pregnancy in this context. Combined with recent meta-analyses that fail to demonstrate improvements in neonatal outcome with tocolytic use, and a poor maternal/fetal side-effect profile, the case for continued use of these drugs needs to be questioned.

On benzofuroindole analogues as smooth muscle relaxants

At least two laboratories have independently reported the synthesis of benzofuroindole compounds having potential therapeutic implications in many disease states including those that involve smooth muscle hyperactivity. Through a series of in vitro screenings, they demonstrated the efficacy (and selectivity) of these compounds to potentiate large conductance calcium- (Ca²⁺-) activated K⁺ (BK_Ca) channels, by far, the most characterized of all Ca²⁺-dependent K⁺ channels. Interestingly, promising benzofuroindole derivatives such as compound 7 (10H-benzo[4,5]furo[3,2-b]indole) and compound 22 (4-chloro-7-trifluoromethyl-10H-benzo[4,5]furo[3,2-b]indole-1-carboxylic acid) both exhibited high bladder (versus aorta) selectivity, making them attractive alternative treatments for bladder overactivity. In recent reports, compound 22 (LDD175 or TBIC) also showed inhibition of ileum and uterine contractions, indicating multiple target tissues, which is not surprising as BK_Ca channels are ubiquitously expressed in the animal and human tissues. In this paper, the authors discuss the value of benzofuroindole compounds and the challenges that need to be overcome if they were considered as smooth muscle relaxants.