The controversy surrounding indomethacin for tocolysis

Indomethacin: The Interplay between Structural Relaxation, Viscous Flow and Crystal Growth

Non-isothermal differential scanning calorimetry (DSC) was used to study the influences of particle size (d_aver) and heating rate (q⁺) on the structural relaxation, crystal growth and decomposition kinetics of amorphous indomethacin. The structural relaxation and decomposition processes exhibited d_aver-independent kinetics, with the q⁺ dependences based on the apparent activation energies of 342 and 106 kJ·mol^-1, respectively. The DSC-measured crystal growth kinetics played a dominant role in the nucleation throughout the total macroscopic amorphous-to-crystalline transformation: the change from the zero-order to the autocatalytic mechanism with increasing q⁺, the significant alteration of kinetics, with the storage below the glass transition temperature, and the accelerated crystallization due to mechanically induced defects. Whereas slow q⁺ led to the formation of the thermodynamically stable γ polymorph, fast q⁺ produced a significant amount of the metastable α polymorph. Mutual correlations between the macroscopic and microscopic crystal growth processes, and between the viscous flow and structural relaxation motions, were discussed based on the values of the corresponding activation energies. Notably, this approach helped us to distinguish between particular crystal growth modes in the case of the powdered indomethacin materials. Ediger's decoupling parameter was used to quantify the relationship between the viscosity and crystal growth. The link between the cooperativity of structural domains, parameters of the Tool-Narayanaswamy-Moynihan relaxation model and microscopic crystal growth was proposed.

Betamethasone as a potential treatment for preterm birth associated with sterile intra-amniotic inflammation: a murine study

OBJECTIVES

Preterm birth remains the leading cause of perinatal morbidity and mortality worldwide. Preterm birth is preceded by spontaneous preterm labor, which is commonly associated with sterile intra-amniotic inflammation; yet, no approved treatment exists for this clinical condition. Corticosteroids are the standard of care to improve neonatal outcomes in women at risk of preterm birth. Herein, we first validated our model of alarmin-induced preterm birth. Next, we investigated whether treatment with betamethasone could prevent preterm birth resulting from sterile intra-amniotic inflammation in mice.

METHODS

Under ultrasound guidance, the first cohort of dams received an intra-amniotic injection of the alarmin high-mobility group box-1 (HMGB1, n=10) or phosphate-buffered saline (PBS, n=9) as controls. A second cohort of dams received HMGB1 intra-amniotically and were subcutaneously treated with betamethasone (n=15) or vehicle (n=15). Dams were observed until delivery, and perinatal outcomes were observed.

RESULTS

Intra-amniotic HMGB1 reduced gestational length (p=0.04), inducing preterm birth in 40% (4/10) of cases, of which 100% (4/4) were categorized as late preterm births. Importantly, treatment with betamethasone extended the gestational length (p=0.02), thereby reducing the rate of preterm birth by 26.6% (from 33.3% [5/15] to 6.7% [1/15]). Treatment with betamethasone did not worsen the rate of neonatal mortality induced by HMGB1 or alter weight gain in the first three weeks of life.

CONCLUSIONS

Treatment with betamethasone prevents preterm birth induced by the alarmin HMGB1. This study supports the potential utility of betamethasone for treating women with sterile intra-amniotic inflammation.

One-Pot Synthesis of Coumarin-Indomethacin Hybrids as COX-2 Targeting Probes for Cancer Imaging

Facile synthesis of 6- or 7-substituted coumarin-indomathacin hybrids (Coum-IDM) has been developed for specific cyclooxygenase-2 (COX-2) binding along with their intrinsic fluorescent properties. A mild and rapid condensation/dehydrative cyclization of 2-hydroxy benzaldehyde with activated indomethacin was carried out in one step under ultrasound irradiation. Coum-IDM₄ was found to be the best of this series as it presented significant binding to COX-2 and exhibited higher fluorescent intensity in cancer cells than in normal cells. Therefore, in the light of drug development tools, this new hybrid system could be a potential targeted probe for COX-2-overexpressed inflammation and cancer-cell tracking.

The effect of antenatal indomethacin on extremely preterm neonatal kidney function

Introduction/Objective: Indomethacin is an effective tocolytic to prevent extremely preterm birth. Prior studies have associated antenatal indomethacin exposure with adverse preterm neonatal intestinal and neurological outcomes. Indomethacin is a nephrotoxic medication that may also affect preterm neonatal kidneys. We sought to evaluate the effect of antenatal indomethacin on extremely preterm neonatal kidney function and acute kidney injury (AKI) in the first week of age.Methods: A retrospective cohort study was conducted on neonates born < 29 weeks at a level III neonatal intensive care unit (NICU) from January 2018-April 2019. Serum creatinine (sCr) values and urine output (UOP) in the first seven days of age and the neonate's peak serum creatinine within the first 30 days were evaluated. Neonatal AKI was defined by the modified neonatal Kidney Disease Improving Global Outcomes (KDIGO) definition including urine output.Results: 17 of the 55 neonates meeting criteria for this study were exposed to indomethacin. The average gestational age at birth was similar between study groups. Maternal preeclampsia was more common among women who did not receive indomethacin (p = 0.021). Indomethacin exposed neonates received more gentamicin (p = 0.024). Overall, staging of the neonatal AKI did not differ significantly between the study groups, regardless of how it was quantified (sCr or UOP) or the duration of time in which the injury developed (7 days or 30 days). Separate analysis of sCr and UOP in the first seven days also failed to show any statistically significant differences between the two groups.Conclusion: In this small cohort study of extremely preterm neonates, those born to mothers treated with indomethacin did not have an increased incidence of AKI compared to neonates born to unexposed mothers. Although no statistically significant differences in UOP or sCr were found, they deserve further evaluation in adequately powered prospective clinical trials. Future prospective studies with long-term follow-up utilizing advanced biomarkers are needed to determine how antenatal indomethacin affects extremely preterm neonatal kidney function in the NICU, during childhood, and as adults.

An Update on Biologic Agents During Pregnancy

Most biological agents are safe to use in pregnancy. Biologic agents may be divided into 4 risk categories: minimal, uncertain, moderate, and high. Treatment options should be individualized to each patient's disease activity, response to medication, and adverse effects. Hydroxychloroquine, sulfasalazine, azathioprine, cyclosporine A, and low-dose aspirin are considered safe. Glucocorticoids may increase the risk of gestational diabetes and gestational hypertension/preeclampsia. Nonsteroidal medication should only be used during the first trimester and for a short period during the second trimester. Limited experience with tumor necrosis factor-α inhibitor medications suggests minimal risk. Methotrexate, mycophenolate, and leflunomide are contraindicated during pregnancy.

Evaluation of the Risk Factors for Acute Kidney Injury in Neonates Exposed to Antenatal Indomethacin

OBJECTIVE

Evidence is limited about important maternal and neonatal risk factors that affect neonatal renal function. The incidence of acute kidney injury (AKI) and identification of associated risk factors in neonates exposed to antenatal indomethacin was studied.

METHODS

A retrospective cohort of neonates exposed to antenatal indomethacin within 1 week of delivery was analyzed for development of AKI up to 15 days of life. Adjusted hazard ratios (HRs) and 95% CIs for AKI risk were calculated in time-dependent Cox proportional hazards models.

RESULTS

Among 143 neonates with mean gestational age of 28.3 ± 2.4 weeks, AKI occurred in 62 (43.3%), lasting a median duration of 144 hours (IQR, 72-216 hours). Neonates with AKI had greater exposure to postnatal NSAIDs (48.4% vs 9.9%, p < 0.001) and inotropes (37.1% vs 3.7%, p < 0.001) compared with neonates without AKI. In multivariable-adjusted models, increased AKI risk was observed with antenatal indomethacin doses received within 24 to 48 hours (HR, 1.6; 95% CI, 1.28-1.94; p = 0.036) and <24 hours (HR, 2.33; 95% CI, 1.17-4.64; p = 0.016) prior to delivery. Further, postnatal NSAIDs (HR, 2.8; 95% CI, 1.03-7.61; p = 0.044), patent ductus arteriosus (HR, 4.04; 95% CI, 1.27-12.89; p = 0.018), and bloodstream infection (HR, 3.01; 95% CI, 1.37-6.60; p = 0.006) were associated significantly with increased risk of AKI following antenatal indomethacin. Neonates with AKI experienced more bloodstream infection, severe intraventricular hemorrhage, patent ductus arteriosus, respiratory distress syndrome, and longer hospitalization.

CONCLUSIONS

Extended risk of AKI with antenatal indomethacin deserves clinical attention among this population at an already increased AKI risk.

The relationship between antenatal indomethacin as a tocolytic drug and neonatal outcomes: a retrospective cohort study

INTRODUCTION

Preterm birth is associated with increased mortality and morbidity. Tocolytic drugs, such as indomethacin, are often used to postpone preterm delivery. Indomethacin has been proven to be more effective than other tocolytic agents in terms of delaying birth but is often prescribed with caution because of its potential association with adverse neonatal outcomes. We aim to study the effects of antenatal indomethacin on neonatal outcomes after controlling for potential confounders, as compared to nifedipine and/or atosiban.

METHODS

In this cohort study, we performed a retrospective analysis of maternal and neonatal data. Women were included if they received indomethacin, nifedipine or atosiban as a tocolytic drug for imminent preterm labor and gave birth at a gestational age (GA) between 23^5/7 and 32^0/7weeks, between 2010 and 2015. Main outcome measures were: neonatal death, necrotizing enterocolitis (NEC), spontaneous intestinal perforation (SIP), intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), patent ductus arteriosus (PDA) and its treatment.

RESULTS

Four hundred seventy-four women, delivering 610 infants were investigated. The incidence of the following adverse neonatal outcomes were significantly higher after indomethacin use: neonatal death (p = .017), NEC (p = .026), SIP (p = .008), PDA (p = .000) and PDA ligation (p = .000). However, these associations showed to be nonsignificant after adjusting for confounders (adjusted odds ratio neonatal mortality 1.6 (0.7-3.8)), NEC 1.6 (0.6-4.4), SIP 2.8 (0.3-30.0), PDA 1.1 (0.6-2.2) and PDA ligation 2.2 (0.7-6.5).

CONCLUSIONS

The presumed association between antenatal indomethacin exposure and several adverse neonatal outcomes may be based upon indication bias. Taking important confounding factors, such as GA at birth and neonatal birth weight into account, antenatal indomethacin exposure does not result in a higher incidence of adverse neonatal outcomes. However, there may be a higher risk for spontaneous intestinal perforation.

Disease specific problems related to drug therapy in pregnancy

Rheumatic diseases occur frequently in women of childbearing years necessitating drug treatment also during a concurrent pregnancy in order to control maternal disease activity and to ensure a successful pregnancy outcome. This survey reviews maternal and fetal side effects of nonsteroidal anti-inflammatory drugs (NSAID) and immunosuppressive agents in pregnant patients. The classic nonselective nonsteroidal anti-inflammatory drugs are not teratogenic, but given in late pregnancy they can induce renal and cardiac side effects in the fetus. Similar effects must be expected of the new, selective Cox2-inhibitors. NSAID should therefore be stopped by gestational week 32. Corticosteroids are frequently necessary to control rheumatic disease flares and for prevention of serious organ manifestations. However, due to an increased risk of oral clefts, high doses (1-2 mg/kg) should be avoided in the first trimester. Among disease modifying drugs, sulfasalazine and antimalarials have the safest record. Cyclosporine and azathioprine can be given throughout pregnancy if disease control requires it. Insufficient data exist for treatment of pregnant patients with TNF-inhibitors and mycophenolate mofetil. The severity of the disease under treatment decides if continuation of one of these drugs is justified. Prophylactic withdrawal of drugs before pregnancy is mandatory for leflunomide and the cytotoxic agents methotrexate and cyclophosphamide. Prepregnancy counselling and careful monitoring during pregnancy help to tailor necessary drug treatment for the benefit of mother and child.

Supramolecular interactions of nonsteroidal anti-inflammatory drug in nanochannels of molecular containers: a spectroscopic, thermogravimetric and microscopic investigation

Supramolecular host-guest complexation between the nonsteroidal anti-inflammatory drug indomethacin (IMC) and molecular containers were investigated. The weakly fluorescent drug molecule becomes highly fluorescent on complexation with different molecular containers, and time-resolved fluorescence emission spectroscopy reveals that the lifetime components of IMC significantly increase in the presence of molecular containers, compared with the lifetimes in neat water. The respective solid host-guest complexes were synthesised and characterised by Fourier transform infrared and (1) H nuclear magnetic resonance spectroscopic analysis. Microscopy techniques were used to analyse modifications of the surface morphology, owing to the formation of supramolecular complexes. The effect of the molecular container on the optical properties of IMC has also been investigated to determine the effect of nanochannels of different size and structure.

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.

The 2'-Trifluoromethyl Analogue of Indomethacin Is a Potent and Selective COX-2 Inhibitor

Indomethacin is a potent, time-dependent, nonselective inhibitor of the cyclooxygenase enzymes (COX-1 and COX-2). Deletion of the 2′-methyl group of indomethacin produces a weak, reversible COX inhibitor, leading us to explore functionality at that position. Here, we report that substitution of the 2′-methyl group of indomethacin with trifluoromethyl produces CF₃–indomethacin, a tight-binding inhibitor with kinetic properties similar to those of indomethacin and unexpected COX-2 selectivity (IC₅₀ mCOX-2 = 267 nM; IC₅₀ oCOX-1 > 100 μM). Studies with site-directed mutants reveal that COX-2 selectivity results from insertion of the CF₃ group into a small hydrophobic pocket formed by Ala-527, Val-349, Ser-530, and Leu-531 and projection of the methoxy group toward a side pocket bordered by Val-523. CF₃–indomethacin inhibited COX-2 activity in human head and neck squamous cell carcinoma cells and exhibited in vivo anti-inflammatory activity in the carrageenan-induced rat paw edema model with similar potency to that of indomethacin.

What really causes necrotising enterocolitis?

Background. One of the most serious gastrointestinal disorders occurring in neonates is necrotising enterocolitis (NEC). It is recognised as the most common intra-abdominal emergency and is the leading cause of short bowel syndrome. With extremely high mortality and morbidity, this enigmatic disease remains a challenge for neonatologists around the world as its definite aetiology has yet to be determined. As current medical knowledge stands, there is no single well-defined cause of NEC. Instead, there are nearly 20 risk factors that are proposed to increase the likelihood of developing NEC. Aims and Objectives. The aim of this project was to conduct a comprehensive literature review around the 20 or so well-documented and less well-documented risk factors for necrotising enterocolitis. Materials and Methods. Searches of the Medline, Embase, and Science direct databases were conducted using the words "necrotising enterocolitis + the risk factor in question" for example, "necrotising enterocolitis + dehydration." Search results were ordered by relevance with bias given to more recent publications. Conclusion. This literature review has demonstrated the complexity of necrotising enterocolitis and emphasised the likely multifactorial aetiology. Further research is needed to investigate the extent to which each risk factor is implicated in necrotising enterocolitis.

Effect of antenatal tocolysis on neonatal outcomes

OBJECTIVE

Detail adverse neonatal effects in pregnancies treated with indomethacin (I), magnesium sulfate (M) or nifedipine (N).

METHODS

Women in acute preterm labor with cervical dilatation 1-6 cm were randomized to receive one of three first-line tocolytic drugs.

RESULTS

There were 317 neonates (I = 103, M = 95, N = 119) whose mothers were treated with tocolytic therapy. There was no difference in gestational age at randomization (average 28.6 weeks' gestation) or at delivery (31.6 weeks' gestation, p = 0.551), birth weight (p = 0.871) or ventilator days (p = 0.089) between the three groups. Neonatal morbidity was not different between the three groups; respiratory distress syndrome (p = 0.086), patent ductus arteriosus (p = 0.592), sepsis (p = 0.590), necrotizing enterocolitis (p = 0.770), intraventricular hemorrhage (p = 0.669) and periventricular leukomalacia (p = 0.124).

CONCLUSIONS

There were no statistically significant differences between the three tocolytics as far as composite neonatal morbidity or mortality was concerned.

Headache in pregnancy: a nuisance or a new sense?

Headache is a very commonly encountered symptom in pregnancy and is usually due to primary headache disorders which are benign in nature. It can however be quite debilitating for some women who may need therapeutic treatment of which there are several options safe to use in pregnancy. It is equally important though to recognise that headache may be a sign of serious underlying pathology. This paper aims to provide a clinically useful guidance for differentiation between primary and secondary headaches in pregnancy. The primary headache disorders and their management in pregnancy are explored in depth with brief overviews of the causes for secondary headaches and their further investigation and management.

Prenatal or postnatal indomethacin exposure and neonatal gut injury associated with isolated intestinal perforation and necrotizing enterocolitis

OBJECTIVE

To examine the role of indomethacin in neonatal gut injury.

STUDY DESIGN

Infants born at gestational age 23 weeks and with birth weights 400-1200 g were included in this prospective prevalence study of neonatal gut injury. Infants with isolated intestinal perforation (IIP) confirmed at laparotomy or at autopsy or with necrotizing enterocolitis (NEC) were identified. Data were abstracted bi-weekly.

RESULT

Among 992 study infants, 58 infants exposed solely to prenatal indomethacin did not show an increased rate of neonatal gut injury. Any postnatal indomethacin exposure (n=611) increased the odds of IIP (OR 4.17, CI, 1.24-14.08, P=0.02) but decreased the odds of NEC (OR 0.65, CI 0.43-0.97, P=0.04). There was a negative association between the timing of indomethacin-exposure and the odds of developing IIP (OR 0.30, CI 0.11-0.83, P=0.02). Compared with NEC, IIP occurred at an earlier age (P<0.05) and was more common (P<0.05) among infants who received early indomethacin (first dose at <12 h of age) to prevent intraventricular hemorrhage than among infants who were treated with late indomethacin for closure of a patent ductus arteriosus (PDA). Unlike the classic hemorrhagic ischemic lesions of NEC in which large areas of tissue were inflamed or necrotic, the IIP lesions were small and discrete.

CONCLUSION

Early (<12 h) postnatal indomethacin exposure was associated with an increased odds of IIP in very low birth weight infants whereas its later use for closure of a PDA appeared to provide protection against NEC. The paradoxical effect of the timing of indomethacin on IIP versus on NEC may be related to the different pathogeneses of the two diseases. Our findings also suggest that PDA may contribute to NEC.

The use during pregnancy of prescription, over-the-counter, and alternative medications among Hispanic women

BACKGROUND

Despite lack of scientific evidence about the safety of complementary and alternative medicines, the reported use of such remedies during pregnancies has increased. This study was undertaken to investigate the use of herbs, vitamins, and over-the-counter and prescription medications among pregnant Hispanic women and reasons for use, and to assess physician-patient level of communication about women's use.

METHODS

A total of 485 Hispanic women were surveyed by means of a self-administered questionnaire immediately postpartum in a public hospital in Houston, Texas. The primary outcome was use of alternative therapies during the prenatal period.

RESULTS

During their pregnancies, 19 percent of the participants took herbs and 47 percent took vitamin supplements, other than prenatal vitamins. The most common reason for using herbs and vitamins was to improve the woman's general health and energy level (59%); a few women (12%) had used them for specific pregnancy-related problems. Overall, 77 percent took prenatal vitamins and 21 percent supplemented with folic acid. The rates of use of over-the-counter and prescription medications were 23 and 29 percent, respectively. The use of prescription medication was two-and-a-half times higher among women with history of medical problems (adjusted OR = 2.59, 95% CI = 1.59-4.25, p = 0.0001). No other factor studied was independently associated with supplement or medication use. One in five women (20%) believed that herbs and vitamins were safer to use than prescription medication or were better at treating medical problems than prescription medicine, and one-third had not disclosed information about supplement use to their physicians.

CONCLUSIONS

Use of herbal remedies does not appear to be a replacement for conventional medicine among most pregnant Hispanic women. Patient education about the risks of alternative therapies may lead to a reduction in intake of alternative medicines and greater disclosure to medical practitioners among this ethnic group.

Indomethacin tocolysis and white matter injury in preterm infants

OBJECTIVE

This study aims to clarify the relationship between indomethacin tocolysis and neonatal white matter injury (WMI) in preterm infants.

METHODS

We conducted a retrospective review of preterm infants born at 24-32 weeks who had sufficient cranial ultrasound examinations (CUS) to determine the incidence and severity of abnormalities. Infants with normal CUS were compared on univariate and multivariate analyses with infants with the different forms of WMI.

RESULTS

On multivariate logistic regression analysis, indomethacin tocolysis was significantly correlated with periventricular echogenicity (PVE; OR 2.84 95% CI 1.41-5.7, p = 0.003), but not with periventricular leucomalacia (PVL; OR 1.83 95% CI0.6-5.6, p = 0.29). Indomethacin was not related to increased risk for periventricular-intraventricular hemorrhage or periventricular hemorrhagic infarction.

CONCLUSION

These findings suggest caution in the use of indomethacin as a tocolytic therapy.

The present and future of tocolysis

This chapter discusses the tocolytic agents currently in use for the treatment of preterm labour and considers them in light of the evidence base. These agents are the beta2 sympathomimetic agonists, magnesium sulphate (MgSO(4)), indomethacin, nifedipine and atosiban. The available evidence for these agents shows that the beta2 agents are effective but have significant maternal side effects and no effect on perinatal outcome. MgSO(4) and glyceryl trinitrate are clearly ineffective. Nifedipine is effective with a low maternal side effect profile and is associated with improved perinatal outcomes. Meta-analyses of the several randomized controlled trials of atosiban show that it is no more effective than other tocolytic therapies. Possible directions for the future will be discussed.

Effect of Placental Fatty Acid Metabolism and Regulation by Peroxisome Proliferator Activated Receptor on Pregnancy and Fetal Outcomes

Fatty acids, particularly the omega-3 and omega-6 essential fatty acids (EFAs), are considered critical nutritional sources for the developing fetus. The placenta governs the fetal supply of fatty acids via two processes: transport and metabolism. Placental fatty acid metabolism can play a critical role in guiding pregnancy and fetal outcome. EFAs can be metabolized to important cell signaling molecules in placenta by several major isoform families including: the Cytochrome P450 subfamily 4A (CYP4A); Cyclooxygenases (COXs); and Lipoxygenases (LOXs). Peroxisome proliferator-activated nuclear receptors (PPARs) have been demonstrated to regulate a number of placental fatty acid/lipid homeostasis-related proteins (e.g., metabolizing enzymes and transporters). The present review summarizes research on the molecular and functional relevance of fatty acid metabolizing enzymes and the role of PPARs in regulating their expression in the mammalian placenta. Elucidating the pathways of placental fatty acid metabolism and the regulatory processes governing these pathways is critical for advancing our understanding of the role of placenta in supplying EFAs to the developing fetus and the potential implications on pregnancy and fetal outcome. A more complete understanding of placental fatty acid disposition may also provide a basis for nutritional/pharmacological interventions to ameliorate the risk of adverse pregnancy and/or fetal outcomes.

The effects of indomethacin tocolysis on the postnatal response of the ductus arteriosus to indomethacin in extremely low birth weight infants

BACKGROUND

Antenal indomethacin reportedly decreases the responses of a symptomatic patent ductus arteriosus (sPDA) to postnatal indomethacin treatment. Whether a similar exposure affects the responses to indomethacin prophylaxis is unknown.

OBJECTIVE

To evaluate the clinical responsiveness of ductus arteriosus to indomethacin prophylaxis and to the treatment of sPDA in extremely low birth weight (ELBW) infants following indomethacin tocolysis.

METHODS

Retrospective cohort study of 58 ELBW infants whose mothers received indomethacin tocolysis (study) and 58 ELBW infants whose mothers did not (controls), matched by gender, gestational age (GA), birth weight and postnatal sPDA management (prophylaxis or early treatment).

RESULTS

Indomethacin was used as a tocolytic at a median dose of 250 mg, for a duration of 2 days, and ending 1 day before delivery. Study and control mothers were comparable in demographics, antenatal steroid use, cesarean delivery, but were different in the incidence of preeclampsia and preterm labor. Study and control infants were similar in birth weight, GA, indomethacin prophylaxis, early sPDA treatment, mortality, necrotizing enterocolitis, severe intraventricular hemorrhage and stage 3-5 retinopathy of prematurity. Seventeen of 43 study and 16 of 43 control infants who received indomethacin prophylaxis developed sPDA and were combined with early treatment sPDA infants (15 to each group). Two of 32 study and two of 31 control infants underwent surgical ligation whereas the remaining were treated with indomethacin. Sixteen of 30 (53%) and 13 of 29 (45%) were successfully treated and did not require ligation. Study infants were divided according to their mothers' indomethacin total dose (28 infants received <or=225 mg and 30 infants received >225 mg). Both subgroups were demographically and clinically comparable and their response to indomethacin prophylaxis and treatment were similar.

CONCLUSION

In ELBW infants, exposure to indomethacin tocolysis does not affect the clinical responsiveness of the ductus arteriosus to prophylaxis or that of the sPDA to indomethacin treatment.

Anti-inflammatory pharmacotherapy during pregnancy

NSAIDs or cyclooxygenase inhibitors (COX inhibitors), including aspirin, are widely used to treat pain, fever and the articular symptoms of chronic rheumatic diseases. Manifestations of connective tissue or autoimmune diseases are commonly treated with glucocorticosteroids. The effect and side effects of NSAIDs depend on the isoforms of cyclooxygenases that they preferentially or selectively inhibit. The use of COX inhibitors has recently been associated with infertility and miscarriage. The classical nonselective COX inhibitors, including aspirin, do not increase the risk of congenital malformations in humans but administered in the latter part of gestation, they can affect pregnancy and the fetus. The ability of nonselective and selective COX inhibitors to prolong gestation has been used by obstetricians to inhibit premature delivery. The vascular effects of prostaglandin inhibitors can cause constriction of the fetal ductus arteriosus and reduce renal blood flow. These complications have been described for most nonselective COX inhibitors but are increasingly reported also for the selective COX-2 inhibitors. Aspirin, which causes irreversible inhibition of cyclooxygenases, differs from other NSAIDs with regard to indication, effects and side effects. Prematurity, which is increased in pregnancies of women with connective tissue diseases, is an additional risk factor for adverse effects of antenatal exposure to NSAIDs. Therefore, treatment with COX inhibitors should be discontinued at week 32 of gestation. The ability of NSAIDs to compromise reproductive function by inhibition of ovulation and as causative agents for miscarriage is still under debate. Glucocorticosteroids given in early pregnancy are a risk factor for the development of oral clefts. Therefore, the daily dose should be kept to <or= 15 mg during the first trimester. High doses of glucocorticosteroids in the second and third trimester are reserved for flares of autoimmune diseases. Intrauterine fetal growth restriction and premature delivery are possible side effects of high doses.

Risk:benefit ratio of nonsteroidal anti-inflammatory drugs in systemic lupus erythematosus

Nearly 80% of patients with systemic lupus erythematosus (SLE) are treated with NSAIDs for fever, arthritis, serositis and headaches. This article reviews currently available literature on non-selective and selective inhibitors of cyclooxygenases, with an emphasis on the efficacy and safety profile reported in SLE patients. All NSAIDs, regardless of their cyclooxygenase selectivity, induced renal side effects including sodium retention and reduction in glomerular filtration rate. In addition, lupus nephritis is a risk factor for NSAID-induced acute renal failure. NSAID-induced hepatotoxicity is increased in SLE patients in addition to cutaneous and allergic reactions. Finally, aseptic meningitis has been reported more frequently in NSAID-treated SLE patients. Nevertheless, NSAIDs can safely be prescribed to most lupus patients provided that their administration is re-evaluated on a regular basis and the patient is closely monitored.

An EP4 receptor agonist prevents indomethacin-induced closure of rat ductus arteriosus in vivo

Indomethacin exerts a strong tocolytic effect by suppressing uterine contractions mediated by prostaglandins. However, indomethacin also induces in utero closure of fetal ductus arteriosus (DA), leading to serious neonatal consequences. Using rats, we tested the effect of an agonist for a subtype of prostaglandin E2 receptor (EP4), ONO-AE1-437 and its prodrug ONO-4819, as a DA dilator during indomethacin treatment. In vitro, ONO-AE1-437 exhibited a potent dilatory effect on DA against O(2)- and indomethacin-induced contractions in a concentration-dependent manner. In vivo, rat dams were given indomethacin (10 mg/kg, p.o.) alone or with ONO-4819 (0.3 micrograms/kg/h, s.c.) on d 21 of gestation and pups were delivered 4 h later through cesarean section to evaluate the ratio of diameter of DA to that of pulmonary artery. Pups from dams with no drug had DA/PA ratio of 0.9 +/- 0.05, whereas those from dams with indomethacin alone had a decreased ratio of 0.2 +/- 0.03. When ONO-4819 was co-administered to the dams, the ratio recovered significantly to 0.7 +/- 0.06. The administration of ONO-4819 to the dams did not induce any increase in the uterine activity. These results suggest that administration of an EP4 agonist in addition to indomethacin might prevent adverse reactions of indomethacin on fetal DA without restricting its tocolytic effects.

Management options for preterm labour in Canada

OBJECTIVES

(1) To determine the current use of treatment options for preterm labour and (2) to review the relative safety and efficacy of each class of tocolytic agent.

METHODS

MEDLINE and the Cochrane Library were searched using the terms "preterm delivery," "preterm labour," and "tocolysis" alone, and in combination with the terms "betamimetics," "ritodrine," "magnesium sulfate," "calcium channel blockers," "nifedipine," "prostaglandin synthetase inhibitors," "indomethacin," "glyceryl trinitrate," "nitroglycerin," "oxytocin antagonists," and "atosiban." Randomized controlled trials (RCTs) that compared the effect of a tocolytic with a placebo or other tocolytic in women with preterm labour were selected. Trials were assessed according to Jadad's validated quality scale for assessing the quality of RCTs. Thirty two RCTs retrieved met the inclusion criteria. Information not evident from RCTs was sought from non-randomized clinical trials, cohort studies, case control studies, case series, and case reports. Data from the Canadian Survey on Tocolytic Use was obtained directly from the Society of Obstetricians and Gynaecologists of Canada (SOGC).

RESULTS

The available evidence on the use of tocolytics to prolong pregnancy fails to show benefits in neonatal survival and reduced disability. This uncertainty of benefit makes the issue of fetal and maternal drug toxicity more important. There is great concern among SOGC members over the lack of effective and safe treatment options for the management of preterm labour.

CONCLUSIONS

Further well-designed placebo-controlled trials are necessary to study the efficacy and safety of tocolytics in managing preterm labour.

Nimesulide, a cyclooxygenase-2 preferential inhibitor, impairs renal function in the newborn rabbit

Tocolysis with nonsteroidal anti-inflammatory drugs (NSAIDs) has been widely accepted for several years. Recently, the use of the cyclooxygenase-2 (COX2) preferential NSAID nimesulide has been proposed. However, data reporting neonatal acute renal failure or irreversible end-stage renal failure after maternal ingestion of nimesulide question the safety of this drug for the fetus and the neonate. Therefore, this study was designed to define the renal effects of nimesulide in newborn rabbits. Experiments were performed in 28 newborn rabbits. Renal function and hemodynamic parameters were measured using inulin and para-aminohippuric acid clearances as markers of GFR and renal blood flow, respectively. After a control period, nimesulide 2, 20, or 200 microg/kg was given as an i.v. bolus, followed by a 0.05, 0.5, or 5 microg.kg(-1).min(-1) infusion. Nimesulide administration induced a significant dose-dependent increase in renal vascular resistance (29, 37, and 92%, respectively), with a concomitant decrease in diuresis (-5, -23, and -44%), GFR (-12, -23, and -47%), and renal blood flow (-23, -23, and -48%). These results are in contrast with recent reports claiming that selective COX2 inhibition could be safer for the kidney than nonselective NSAIDs. These experiments confirm that prostaglandins, by maintaining renal vasodilation, play a key role in the delicate balance regulating neonatal GFR. We conclude that COX2-selective/preferential inhibitors thus should be prescribed with the same caution as nonselective NSAIDs during pregnancy and in the neonatal period.

Acute management of preterm labor

We are continually reminded that the preterm birth rate has failed to improve; in fact, it has increased over the last 20 years. Much of this increase is related to the tremendous strides made by neonatologists and the resulting increased willingness of obstetricians to deliver preterm babies from hostile intrauterine environments. However, there is still much to learn concerning the pathogenesis, accurate early detection, treatment, and prevention of spontaneous preterm labor. This article concentrates on the clinical diagnosis and acute management of this enigmatic clinical problem.

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

OBJECTIVE

Preterm labor is often a prelude to early births and the significant attendant burden of infant morbidity and mortality. Treatment consists of bedrest, hydration, pharmacologic interventions, and combinations of these. We systematically reviewed the effectiveness of tocolytics to stop uterine contractions (first-line therapy) or maintain quiescence (maintenance therapy). Our objective was to evaluate the evidence on the benefits and harms of five classes of tocolytic therapy for treating uterine contractions related to preterm labor--beta-mimetics, calcium channel blockers, magnesium, nonsteroidal anti-inflammatory agents, and ethanol.

STUDY DESIGN

Reports of randomized controlled trials and other study designs in English, French, and German identified from searches of MEDLINE, EMBASE, specialized databases, bibliographies of review articles, unpublished literature, and discussions with investigators in the field were identified. Studies on women with preterm labor between 1966 and February 1999 that met our inclusion criteria were included. Through dual review, we abstracted the following information: study design and masking; definitions of preterm labor and successful tocolysis; patient inclusion/exclusion characteristics; patient demographic characteristics; drug and cointerventions; and numerous birth, maternal, and neonatal outcome measures.

RESULTS

Of the 256 articles evaluated, we abstracted data from 60 first-line and 15 maintenance studies. Of these, 16 first-line and 8 maintenance studies met more stringent requirements for meta-analyses. Studies of first-line tocolysis (grade Fair) reveal a mixed outcome pattern with small improvement in pregnancy prolongation and birth at term relative to placebo. Data were insufficient to show directly a beneficial effect on neonatal morbidity or mortality. Ethanol was less beneficial than, and beta-mimetics were not superior to, other tocolytic options. Maintenance tocolytics (grade Poor) showed no improvements in birth or infant outcomes relative to placebo; these results were confirmed through meta-analysis. In contrast to other tocolytic treatments, maternal harms from beta-mimetics were rated High; all tocolytics were rated as Low risk for short-term neonatal harms.

CONCLUSIONS

Management of uterine contractions with first-line tocolytic therapy can prolong gestation. Among the tocolytics, however, beta-mimetics appear not to be better than other drugs and pose significant potential harms for mothers; ethanol remains an inappropriate therapy. Continued maintenance tocolytic therapy has little or no value.

Risk factors for intraventricular hemorrhage in very low birth weight premature infants: a retrospective case-control study

OBJECTIVE

High-grade intraventricular hemorrhage (IVH) is an important cause of severe cognitive and motor neurologic impairment in very low birth weight infants and is associated with a high mortality rate. The risk of IVH is inversely related to gestational age and birth weight. Previous studies have proposed a number of risk factors for IVH; however, lack of adequate matching for gestational age and birth weight may have confounded the results. The purpose of this study was to identify variables that affect the risk of high-grade IVH, using a retrospective and case-control clinical study.

METHODS

From a cohort of 641 consecutive preterm infants with a birth weight of <1500 g, 36 infants with IVH grade 3 and/or 4 were identified. A control group of 69 infants, closely matched for gestational age and birth weight, was selected. Maternal factors, labor and delivery characteristics, and neonatal parameters were collected in both groups. Results of cranial ultrasound examinations, whether routine or performed in presence of clinical suspicion, were also collected. Univariate analysis and multivariate logistic regression analysis were performed.

RESULTS

High fraction of inspired oxygen in the first 24 hours, pneumothorax, fertility treatment (mostly IVF), and early sepsis were associated with an increased risk of IVH. A higher number of suctioning procedures, a higher first hematocrit, and a relatively low arterial pressure of carbon dioxide during the first 24 hours of life were associated with a lower occurrence. In the multivariate logistic regression model, early sepsis (odds ratio [OR]: 8.19; 95% confidence interval [CI]: 1.55-43.1) and fertility treatment (OR: 4.34; 95% CI: 1.42-13.3) were associated with a greater risk of high-grade IVH, whereas for every dose of antenatal steroid treatment there was a lower risk of high-grade IVH (OR: 0.52; 95% CI: 0.30-0.90) and each decrease in a mmHg unit of arterial pressure of carbon dioxide during the first 24 hours was associated with a lower risk of IVH (OR: 0.91; 95% CI: 0.83-0.98). This multivariate model had a sensitivity of 77%, a specificity of 75%, and a positive predictive value of 76%. The area under the curve derived from the receiver operator characteristic plots is 0.82.

CONCLUSIONS

Our results confirm that the development of IVH is associated with early sepsis and failure to give antenatal steroid treatment. We propose that fertility treatment (and especially IVF) may be a new risk factor, and more research is needed to assess its role.

An update on the controversies of tocolytic therapy for the prevention of preterm birth

Preterm birth is the major cause of perinatal mortality and morbidity in the developed world. Where there are no contraindications to their use, tocolytics can improve neonatal survival rates by approximately 3% per day between 23 and 27 weeks gestation with a concomitant reduction in morbidity. The ultimate aim of tocolytic therapy is to prolong pregnancy until growth and maturation is complete, but even short-term delay may enable the administration of antepartum glucocorticoids to reduce hyaline membrane disease or to arrange transfer to a center with neonatal intensive care facilities. Both of these have been shown to reduce neonatal mortality and morbidity. Until recently, none of the currently used tocolytics, whether licensed or unlicensed, were developed specifically for the inhibition of preterm labor and consequently, they exhibit various potentially serious side-effects. As a result of the recent licensing of the oxytocin antagonist, atosiban, developed for the treatment of preterm labor and due to its high utero-specificity, obstetricians have experienced an advance in their options for the management of spontaneous preterm labor.

Expression of cyclooxygenase-2 in embryonic and fetal tissues during organogenesis and late pregnancy

BACKGROUND

Cyclooxygenase (COX) catalyzes the committed step in prostaglandin biosynthesis and exists as two related but unique isoforms, COX-1 (constitutive) and COX-2 (inducible). Prostaglandins (PGs) are known to have many important functions in reproduction, such as placentation and decidualization. Studies with the COX-1 and COX-2 knockout mice have demonstrated that COX-2, but not COX-1, is crucial for normal ovulation, implantation, and decidualization, suggesting that COX-2-derived PGs are important during the initial stages of pregnancy. Although the COX-2 knockout mice did not exhibit any abnormalities at birth, relatively little information exists with regard to the expression of COX-2 in the fetus during development.

METHODS

In order to understand the role of COX-2 throughout pregnancy, we characterized the cell type and the temporal expression of inducible COX-2 throughout embryonic and fetal development in the rat (n = 22) by immunohistochemistry and in situ hybridization.

RESULTS

High levels of COX-2 expression were seen in decidualized uterine tissue on gestation days 7-13 and then in the fetal membranes on gestation days 17-20. Cyclooxygenase-2 expression was not detectable in any tissues from developing embryos during gestation days 7-13, but was observed in the fetal growth period (gestation days 15-20) in the skin, heart, cartilage, and the kidney.

CONCLUSIONS

No COX-2 expression was seen in fetal tissues at days 7-13 of gestation, but was seen in various tissues at days 15-17 of gestation. These observations suggest that COX-2 may be important in mid to late pregnancy through an effect on fetal organ growth, but not in the organogenetic phase of fetal development.

The effect of in utero exposure to indomethacin on the need for surgical closure of a patent ductus arteriosus in the neonate

OBJECTIVE

Our purpose was to determine the effect of in utero exposure to indomethacin on the need for surgical closure of a patent ductus arteriosus (PDA).

STUDY DESIGN

Perinatal variables were compared between infants at <32 weeks who required surgical closure of PDA after failed medical management and those who did not. Statistical analysis was performed by Student t, Mann-Whitney, chi(2), and multiple logistic regression tests.

RESULTS

Eight of 77 infants with PDA failed therapy and required surgery. Maternal demographics, gestational age, birth weight, and delivery route were similar in both groups. In utero exposure to indomethacin was more common in neonates requiring surgery versus those who did not, particularly when exposure was for >72 hours (50.0% vs 8.7%, odds ratio 10.5, 95% CI 1.6-72.1, P =.008).

CONCLUSION

Need for surgical closure of PDA appears to be increased by in utero indomethacin exposure. These findings should be considered in the overall context of the risk versus benefits of tocolysis.

In vitro study of tocolytic effect of rofecoxib, a specific cyclo-oxygenase 2 inhibitor. Comparison and combination with other tocolytic agents

OBJECTIVE

The aim of this work was to study and compare the tocolytic effects of rofecoxib with indomethacin, ritodrine, nicardipine and atosiban. We also studied the combination of rofecoxib with each agent.

DESIGN

In vitro animal experimental study.

SETTING

Non-selective cyclo-oxygenase (COX) inhibitors have potent tocolytic effect. However, they also have major fetal side effects that seem to be due to COX-1 inhibition. A specific COX-2 inhibitor could be a potent tocolytic agent with less fetal toxicity.

SAMPLE

Myometrial strips from pregnant Wistar rats at 18 days of gestation.

METHODS

Isometric tension was recorded from 112 pregnant rat myometrial strips in vitro. Strips were exposed to increase molar concentration of one drug or combination.

MAIN OUTCOME MEASURES

Contractile activity was assessed by calculating the area under the curve, to obtain a dose-response curve of each drug. EC50 and mean maximal inhibiting concentration were compared using ANOVA. Chemical interaction was defined for each combination.

RESULTS

The in vitro tocolytic effect of rofecoxib was demonstrated. Contractile activity stopped at a concentration of 1.6 x 10(-7) M. Effective concentrations were 1000 times less than for indomethacin and significantly lower than ritodrine and atosiban. Rofecoxib combined with ritodrine had a synergic effect. Other combinations only had an additive effect.

CONCLUSIONS

Rofecoxib has a potent tocolytic effect in vitro. The high specificity and low effective concentrations of COX-2 may result in low fetal toxicity. Animal fetal side effects need to be explored.

Clearance and disposition of indometacin in chronically instrumented fetal lambs following a 3-day continuous intravenous infusion

Indometacin is used in pregnancy for the treatment of premature labour, but there are limited data on the disposition of the drug in the fetus. In order to elucidate fetal indometacin pharmacokinetics at plasma levels and duration comparable with those occurring with use of the drug for tocolysis in humans, indometacin was administered at doses of 1.9 (low dose, LD; n = 5) or 7.5 (high dose, HD; n = 9) microg min(-1) to steady state over a 3-day period in chronically instrumented fetal lambs. Indometacin concentrations in biological fluid samples were analysed by a sensitive capillary gas chromatography-electron capture detection method. The mean steady-state fetal arterial plasma indometacin concentrations were 68.6+/-16.5 ng mL(-1) in the LD infusion and 230.3+/-28.8 ng mL(-1) in the HD infusion. Indometacin concentrations in amniotic fluid were approximately 10% of those in fetal plasma, and below assay detection limits in tracheal fluid. Total body clearance (TBC) in the LD and HD infusions were not different and the overall mean was 11.3+/-1.2 mL min(-1) kg(-1). In the 11 experiments where paired fetal arterial and umbilical venous samples were collected, the extraction of indometacin across the placenta averaged only 5.2+/-1.1%, indicating low placental permeability to the drug in sheep. However, fetal placental clearance (CLpl) of indometacin (10.0+/-2.5 mL min(-1) kg(-1), n = 10) averaged 115.1+/-41.2% of TBC in these animals and the calculated value for fetal non-placental clearance (0.6+/-2.8 mL min(-1) kg(-1)) was not significantly different from zero. Fetal renal clearance of intact indometacin (3.8+/-1.1 microL min(-1) kg(-1); n = 12) was also very low. However, treatment of fetal urine with glucuronidase indicated the presence of glucuronide conjugates and these comprised 69.9+/-8.2% of the total drug concentration (i.e. intact+conjugated) in urine. Thus, the fetal lamb appears to be able to glucuronidate indometacin, but the contribution of this and other non-placental routes to overall fetal elimination of the drug appear minimal. CLpl of the drug is also low owing to the physicochemical properties of indometacin (high polarity) and the permeability characteristics of the sheep placenta.

Treatment of preterm labor

The ultimate goal of treating preterm labor is to prolong the pregnancy long enough to decrease the incidence of neonatal mortality and morbidity associated with prematurity, while minimizing maternal and fetal risks. There are many controversies in treating preterm labor. Much of this controversy stems from the difficulty in establishing efficacy and safety of interventions and uncertainty of the diagnosis of preterm labor. This article outlines conventional measures and tocolytic therapy directed at prolonging the pregnancy. A review of the effect of tocolytic agents, administration, side effects, and nursing interventions is included. Key words: preterm labor treatment,

Preterm labour

Studies in the past year have clarified the roles of inflammatory mediators in preterm labour. Exploration of possible genetic predisposition is just beginning. Ultrasound measurement of cervical length has the potential to predict women at risk of preterm delivery several weeks before it occurs. Biochemical testing such as fetal fibronectin can possibly increase its predictive value and differentiate true preterm labour from more innocent preterm contractions. The use of antibiotics for preterm premature rupture of membranes has been clarified with the ORACLE I trial, which shows health benefits for the neonate with the use of erythromycin, whereas antibiotics do not seem to play a beneficial role in spontaneous preterm labour without evidence of clinical infection. There have been further studies suggesting that agents other than beta-agonists are preferable for acute tocolysis and that repeated doses of corticosteroids should be used with caution.

Adverse and beneficial effects of tocolytic therapy

In addition to questions raised about the efficacy of many tocolytics, appropriate concern has been voiced about the safety of these potent drugs. Although some degree of risk for adverse effects with drugs promising a strong therapeutic effect can be accepted, caution needs to be exercised when benefits are marginal or unproven. Unfortunately, some of the tocolytics, most notably the betamimetics and magnesium sulfate, have been found to have considerable potential for adverse maternal cardiovascular and respiratory effects. Although less clearly established, the use of indomethacin appears to be associated with increased fetal and neonatal risks. Concerning magnesium sulfate, in addition to the well-known maternal effects, the accumulating evidence showing an increased frequency of adverse outcomes in the fetus and neonate has led to the recommendations to abandon its use entirely as a tocolytic. Given the limitations of our current state of knowledge, nifedipine would appear to be among the more efficacious and safer tocolytics available to use when properly indicated.