Assessing the Neonatal Safety of Indomethacin Tocolysis

Association of Intrapartum Drugs with Spontaneous Intestinal Perforation: A Single-Center Retrospective Review

OBJECTIVE

 Spontaneous intestinal perforation (SIP) occurs commonly in extremely low gestational age newborns (ELGANs; <30 weeks' GA). Early, concurrent neonatal use of indomethacin (Neo_IN) and hydrocortisone (Neo_HC) is a known risk for SIP. Mothers in premature labor often receive indomethacin (Mat_IN) for tocolysis and steroids (Mat_S) for fetal maturation. Coincidentally, ELGANs may receive Neo_IN or Neo_HC within the first week of life. There are limited data on the effect of combined exposures to maternal and neonatal medications. We hypothesized that proximity exposure to these medications may increase the risk of SIP.

STUDY DESIGN

 We reviewed the medical records of ELGANs from June 2014 to December 2019 at a single level III neonatal intensive care unit. We compared antenatal and postnatal indomethacin and steroid use between neonates with and without SIP. For analysis, chi-square, Student's t-test, Fisher's exact test, and Mann-Whitney U tests were used.

RESULTS

 Among 417 ELGANs, SIP was diagnosed in 23, predominantly in neonates < 26 weeks' GA (n = 21/126, 16.7%). Risk factors analysis focused on this GA cohort in which SIP was most prevalent. Mat_IN administration within 2 days of delivery increased SIP risk (odds ratio: 3; 95% confidence interval: 1.25-7.94; p = 0.036). Neo_HC was not independently associated with SIP (p = 0.38). A higher proportion of SIP group had close temporal exposure of Mat_IN and Neo_HC compared with the non-SIP group, though not statistically significant (14 vs. 7%, p = 0.24).

CONCLUSION

 Peripartum Mat_IN was associated with increased risk for SIP in this small study sample. Larger studies are needed to further delineate SIP risk from the interaction of peripartum maternal medication with early postnatal therapies and disease pathophysiology.

KEY POINTS

· Perinatal indomethacin is associated with SIP in preterm infants born at less than 26 weeks.. · Temporal proximity of prenatal/postnatal medication exposure matters.. · Indomethacin and Hydrocortisone the risks, benefits, and timing related to SIP..

A novel role for PGE2-EP4 in the developmental programming of the mouse ductus arteriosus: consequences for vessel maturation and function

The ductus arteriosus (DA) is a vascular shunt that allows oxygenated blood to bypass the developing lungs in utero. Fetal DA patency requires vasodilatory signaling via the prostaglandin E2 (PGE2) receptor EP4. However, in humans and mice, disrupted PGE2-EP4 signaling in utero causes unexpected patency of the DA (PDA) after birth, suggesting another role for EP4 during development. We used EP4-knockout (KO) mice and acute versus chronic pharmacological approaches to investigate EP4 signaling in DA development and function. Expression analyses identified EP4 as the primary EP receptor in the DA from midgestation to term; inhibitor studies verified EP4 as the primary dilator during this period. Chronic antagonism recapitulated the EP4 KO phenotype and revealed a narrow developmental window when EP4 stimulation is required for postnatal DA closure. Myography studies indicate that despite reduced contractile properties, the EP4 KO DA maintains an intact oxygen response. In newborns, hyperoxia constricted the EP4 KO DA but survival was not improved, and permanent remodeling was disrupted. Vasomotion and increased nitric oxide (NO) sensitivity in the EP4 KO DA suggest incomplete DA development. Analysis of DA maturity markers confirmed a partially immature EP4 KO DA phenotype. Together, our data suggest that EP4 signaling in late gestation plays a key developmental role in establishing a functional term DA. When disrupted in EP4 KO mice, the postnatal DA exhibits signaling and contractile properties characteristic of an immature DA, including impairments in the first, muscular phase of DA closure, in addition to known abnormalities in the second permanent remodeling phase.NEW & NOTEWORTHY EP4 is the primary EP receptor in the ductus arteriosus (DA) and is critical during late gestation for its development and eventual closure. The "paradoxical" patent DA (PDA) phenotype of EP4-knockout mice arises from a combination of impaired contractile potential, altered signaling properties, and a failure to remodel associated with an underdeveloped immature vessel. These findings provide new mechanistic insights into women who receive NSAIDs to treat preterm labor, whose infants have unexplained PDA.

Efficacy of long-term indomethacin therapy in prolonging pregnancy after fetoscopic laser surgery for twin-to-twin transfusion syndrome: a collaborative cohort study

OBJECTIVE

To evaluate the efficacy of long-term indomethacin therapy (LIT) in prolonging pregnancy and reducing spontaneous preterm birth (PTB) in patients undergoing fetoscopic laser surgery (FLS) for the management of twin-to-twin transfusion syndrome (TTTS).

DESIGN

Retrospective cohort study of prospectively collected data.

SETTING

Collaborative multicentre study.

POPULATION

Five hundred and fifty-seven consecutive TTTS cases that underwent FLS.

METHODS

Long-term indomethacin therapy was defined as indomethacin use for at least 48 hours. Log-binomial regression was used to estimate the relative risk of PTB in the LIT group compared with a non-LIT group. Cox regression was used to evaluate the association between LIT use and FLS-to-delivery survival.

MAIN OUTCOME MEASURES

Gestational age (GA) at delivery.

RESULTS

Among the 411 pregnancies included, a total of 180 patients (43.8%) received LIT after FLS and 231 patients (56.2%) did not. Median GA at fetal intervention did not differ between groups (20.4 weeks). Median GA at delivery was significantly higher in the LIT group (33.6 weeks) compared with the non-LIT group (31.1 weeks; P < 0.001). FLS-to-delivery interval was significantly longer in the LIT group (P < 0.001). The risks of PTB before 34, 32, 28 and 26 weeks of gestation were all significantly lower in the LIT group compared with the non-LIT group (relative risks 0.69, 0.51, 0.37 and 0.18, respectively). The number needed to treat with LIT to prevent one PTB before 32 weeks of gestation was four, and to prevent one PTB before 34 weeks was five.

CONCLUSION

Long-term indomethacin after FLS for TTTS was found to be associated with prolongation of pregnancy and reduced risk for PTB.

TWEETABLE ABSTRACT

Long-term indomethacin used after fetoscopic laser surgery for twin-to-twin transfusion syndrome is effective in prolonging pregnancy and reducing the risk for preterm birth; especially extreme preterm birth.

Guideline No. 401: Sonographic Cervical Length in Singleton Pregnancies: Techniques and Clinical Applications

OBJECTIVES

• To assess the association between sonography-derived cervical length measurement and preterm birth. • To describe the various techniques to measure cervical length using sonography. • To review the natural history of the short cervix. • To review the clinical uses, predictive ability, and utility of sonography-measured short cervix.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

INTENDED USERS

Clinicians involved in the obstetrical management or cervical imaging of patients at increased risk of a short cervix.

TARGET POPULATION

Women at increased risk of a short cervix or at risk of preterm birth.

EVIDENCE

Literature published up to June 2019 was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, cervical insufficiency, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made and graded according to the rankings of the Canadian Task Force on Preventive Health Care (Online Appendix Table A1).

BENEFITS, HARMS, COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the sonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth. SUMMARY STATEMENTS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES): RECOMMENDATIONS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES).

Antenatal Risk Factors Associated with Spontaneous Intestinal Perforation in Preterm Infants Receiving Postnatal Indomethacin

OBJECTIVE

To determine if antenatal variables affect the risk of spontaneous intestinal perforation (SIP) among preterm infants when prophylactic indomethacin is used.

STUDY DESIGN

Retrospective case-control study of infants <29 weeks of gestational age between January 2010 and June 2018 at one hospital. SIP was defined as acute abdominal distension and pneumoperitoneum without signs of necrotizing enterocolitis at <14 days of life. Each case (n = 57) was matched with 2 controls (n = 114) for gestational age and birth year. Maternal and infant data were abstracted until the SIP or equivalent day for controls. Univariate analyses were followed by adjusted conditional logistic regressions and reported as OR and 95% CI.

RESULTS

Mothers of cases were younger, more often delivering multiples (31% vs 14%, P = .007), and less abruptions (15% vs 29%, P = .045) but did not differ in intra-partum betamethasone, magnesium, or indomethacin use. Prophylactic indomethacin was given on day 1 to 99% of infants. SIP was associated with a shorter interval from last betamethasone dose to delivery (46 hours vs 96 hours, P = .01). Dopamine use (14% vs 4%, P = .02), volume expansion (23% vs 8%, P = .003), and high grade intraventricular hemorrhage (28% vs 8%, P = .0008) were related postnatal factors. The adjusted odds of SIP increased by 1% for each hour decrease between the last dose of betamethasone and delivery (OR 1.01, 95% CI 1.002-1.019) and with multiple births (OR 2.66, 95% CI 1.05-6.77).

CONCLUSIONS

Antenatal betamethasone given shortly before delivery is associated with an increased risk of SIP. Potential interaction with medications such as postnatal indomethacin needs study.

Effect of In Utero Non-Steroidal Anti-Inflammatory Drug Therapy for Severe Ebstein Anomaly or Tricuspid Valve Dysplasia (NSAID Therapy for Fetal Ebstein anomaly)

Ebstein anomaly (EA) and tricuspid valve dysplasia (TVD) are rare congenital malformations associated with nearly 50% mortality when diagnosed in utero. The diseases often produce severe tricuspid regurgitation (TR) in the fetus and in some cases, pulmonary regurgitation (PR) and circular shunting ensue. Since the ductus arteriosus (DA) plays a critical role in the circular shunt and may be constricted by transplacental nonsteroidal anti-inflammatory drugs (NSAIDs), we sought to assess the effect of NSAIDs on fetuses with EA/TVD. We reviewed mothers of singleton fetuses with EA/TVD and PR, indicative of circular shunting, who were offered NSAIDs at multiple centers from 2010 to 2018. Initial dosing consisted of indomethacin, followed by ibuprofen in most cases. Twenty-one patients at 10 centers were offered therapy at a median gestational age (GA) of 30.0 weeks (range: 20.9 to 34.9). Most (15/21 = 71%) mothers received NSAIDs, and 12 of 15 (80%) achieved DA constriction after a median of 2.0 days (1.0 to 6.0). All fetuses with DA constriction had improved PR; 92% had improved Doppler patterns. Median GA at pregnancy outcome (live-birth or fetal demise) was 36.1 weeks (30.7 to 39.0) in fetuses with DA constriction versus 33 weeks (23.3 to 37.3) in fetuses who did not receive NSAIDs or achieve DA constriction (p = 0.040). Eleven of 12 patients (92%) with DA constriction survived to live-birth, whereas 4 of 9 patients (44%) who did not receive NSAIDs or achieve DA constriction survived (p = 0.046). In conclusion, our findings demonstrate the proof of concept that NSAIDs mitigate circular shunt physiology by DA constriction and improve PR among fetuses with severe EA/TVD. Although the early results are encouraging, further investigation is necessary to determine safety and efficacy.

Safety and Efficacy of Tocolytics for the Treatment of Spontaneous Preterm Labour

BACKGROUND

Preterm birth is the major cause of perinatal mortality and morbidity worldwide. Attempts to reduce the burden may be proactive using biochemical or biophysical prediction and preventative measures. If these efforts fail, then the approach may have to be reactive using tocolytics to inhibit spontaneous preterm labour.

OBJECTIVE

We have reviewed the evidence concerning the safety and efficacy of various classes of tocolytic agents.

RESULTS

The evidence to support the use of magnesium sulfate or nitric oxide donors as a tocolytic is poor. Compared to placebo or no treatment, there is evidence to support the efficacy of calcium channel blockers (mainly nifedipine), prostaglandin synthetase inhibitors (mainly indomethacin and sulindac), oxytocin receptor antagonists (mainly atosiban) and β2-agonists (mainly ritodrine, terbutaline, salbutamol and fenoterol). Maternal safety concerns have reduced the use of β2-agonists. Fetal safety and gestational age restrictions have largely condemned prostaglandin synthetase inhibitors to second-line therapy. First-line therapy in Europe and other parts of the world outside the USA and Australia is limited to calcium channel blockers and oxytocin receptor antagonists. With respect to efficacy, atosiban and nifedipine are similar, but the robustness of the evidence favours atosiban. With respect to safety, atosiban is clearly the safest tocolytic as there are fetomaternal concerns with nifedipine, particularly in high daily doses.

CONCLUSION

The perfect tocolytic that is uniformly effective and safe does not exist. Cost, licensing and informed consent are considerations involved in the choice. Efforts continue to develop and introduce other or better agents, including novel compounds such as progesterone, PGF2α antagonists and statins.

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.

Prolonged early antenatal indomethacin exposure is safe for fetus and neonate. J Matern Fetal Neonatal Med 2019;34:167-176. [PMID: 30905227 DOI: 10.1080/14767058.2019.1599351]

Objective: To evaluate fetal and neonatal safety of early-onset long-term antenatal indomethacin treatment (LIT) for short cervix.Methods: In this cohort study, women started LIT for short cervix (<25 mm) before completing 25 weeks. They followed a standardized regiment of oral indomethacin: 100 mg loading, 50 mg qid for 48 h, 25 mg qid until delivery or at 32 weeks gestational age (GA), whichever comes first. Weekly monitoring for oligohydramnios and ductus arteriosus (DA) constriction included confirmation of compliance with treatment/dose. This approach is established in our clinical practice. To identify LIT complications separate from prematurity, each neonate exposed to LIT were matched to two unexposed neonatal controls within ±3 days of GA of delivery and birth weight of ±10%. Odds ratios for neonatal variables included pulmonary hemorrhage, patent DA (PDA) requiring medical or surgical correction, necrotizing enterocolitis (NEC), spontaneous intestinal perforation (SIP), intraventricular hemorrhage (IVH) grade III-IV, other intracranial hemorrhage (ICH), neonatal mortality, calculated individually, and for total composite morbidity. Statistical determinants of neonatal morbidity were assessed using binary logistic regression. Exposure to LIT, maternal age, parity, BMI, GA at delivery, birth-weight (BW), neonatal gender, cord artery pH, and 5-min Apgar score were independent variables.Results: 166 LIT cases were matched with 332 controls. LIT median duration was 49 (3-108) days. Mean delivery GA was 34 weeks. LIT was stopped for 5 patients (2.9%) with oligohydramnios and 1 (0.6%) with DA constriction, without consequent morbidity. 71 cases (43%) completed LIT, stopping at 32 weeks. 95 stopped early for preterm premature ruptures of membranes (PPROM) (20%), active labor (11%) or patient choice (22%). Odds of any individual complication did not differ between treated cases and controls. LIT was not a statistical determinant of composite morbidity or any individual neonatal problem.Conclusion: Continuous early-onset indomethacin exposure, up to 15 weeks antenatally, did not increase fetal or neonatal complications. This level of safety is permissive to a randomized trial of indomethacin for the treatment of short cervix.

Tocolysis: A Review of the Literature

Importance

Preterm delivery represents an important cause of infant morbidity and mortality. Various tocolytics have been studied with the objective of stopping preterm labor, increasing gestational age at delivery, and preventing complications related to preterm birth.

Objective

This review aims to summarize the major classes of tocolytics and review the evidence regarding use of each.

Evidence Acquisition

A PubMed search of the following terms was performed to gather relevant data: "tocolytic," "preterm labor," "preterm delivery," "PPROM," "magnesium," "indomethacin," "nifedipine," and "betamimetics."

Results

The benefits and risks of nonsteroid anti-inflammatory drugs, calcium channel blockers, magnesium, and betamimetics are reviewed. Calcium channel blockers afford superior outcomes in terms of prolonging gestation and decreasing neonatal morbidity and mortality with the fewest adverse effects.

Conclusions and Relevance

Tocolytics, particularly calcium channel blockers, may provide benefit to pregnant women and their infants. Their use should be tailored to the particular clinical circumstances of the patient and used in conjunction with other management strategies (e.g., administration of corticosteroids for fetal lung maturation or magnesium for neuroprotection and transfer to a tertiary medical center). Further research and professional guidelines are needed on optimal use of these agents.

A comparative study on the efficacy of nifedipine and indomethacin for prevention of preterm birth as monotherapy and combination therapy: a randomized clinical trial

Introduction: Preterm delivery is an important issue in obstetrics, which is the most common cause of neonatal mortality and morbidity. Therefore, finding a way to prevent it is always under serious concern.Objective: The study aimed to compare the efficacy of two tocolytic agents, nifedipine and indomethacin, for inhibiting preterm uterine contractions as monotherapy and combination therapy.Materials and methods: A double-blind randomized clinical trial was performed on pregnant women with gestational age of 26-34 weeks of pregnancy who referred to hospital for preterm labor. They were randomly assigned to three groups. Indomethacin plus placebo, nifedipine plus placebo, and a combination of indomethacin and nifedipine were administered to the three groups. Inhibiting contractions for 2 hours and prevention of delivery for 48 hours and 7 days were evaluated. Also, duration of pregnancy, the number of preterm births, and the interval between entering the study and delivery were compared between three groups.Results: One hundred fifty women were eligible for the study. Two women in the nifedipine group and one woman in the combined group were excluded from the study because of hypotension. The women of the three groups did not have significant difference according to age, BMI, gravidity, parity, Bishop score, gestational age, and the number of contractions at entering the study. Thirty-six women (72%) in the indomethacin group, 36 women (72%) in the nifedipine group, and 41 women (89.4%) in the combination group had stopped contractions within the first 2 hours of intervention (p = .002). Inhibiting contractions for 48 hours (p = .003), inhibiting contractions for 7 days (p = .021), gestational age at birth (p = .001), number of pregnancies more than 37 weeks (p = .007), and neonatal weight (p = .020) were significantly more in the combination group.Conclusion: Combination therapy with nifedipine and indomethacin was more effective than monotherapy with either of these two medications for inhibiting preterm labor, delaying delivery, and prolongation of the duration of pregnancy.

Acute Tocolysis - a Critical Analysis of Evidence-Based Data

Tocolysis is among the most common obstetric measures. The objective is to prolong the pregnancy by at least 48 hours to complete foetal lung maturation and for the in-utero transfer of the pregnant woman to a perinatal centre. The indication for tocolysis is regular, premature contractions (≥ 4/20 min) and a dynamic shortening of the cervical length/cervical opening between 22 + 0 to 33 + 6 weeks of pregnancy. In this connection, the cervical length measured on ultrasound and the determination of biomarkers in the cervicovaginal secretions can be important decision-making aids. Beta sympathomimetics should no longer be used due to the high rate of severe maternal adverse effects. Given controversial data, magnesium sulphate is no longer recommended for tocolysis in current guidelines. Atosiban is as effective for prolonging pregnancy as beta sympathomimetics and nifedipine, has the lowest rate of maternal adverse effects, but also the highest drug costs. Nifedipine and indomethacin are recommended in international guidelines for acute tocolysis, however there are indications of increased neonatal morbidity following indomethacin. Current problems are, above all, the lack of randomised, controlled comparative and placebo-controlled studies, the data which are controversial to some extent, and the insufficient evidence of tocolytics to significantly improve the neonatal outcome.

Effects of antenatal indomethacin on ductus arteriosus early closure and on adverse outcomes in preterm neonates

Introduction: Premature birth is a leading cause of neonatal morbidity and mortality. Since gestational age at birth is the most important predictive factor of adverse neonatal outcomes, strategies to postpone premature labor are of major importance. Studies on tocolytic drugs show that COX inhibitors such as indomethacin are superior to others in terms of efficiency in delaying birth, but results concerning neonatal outcomes associated with prenatal exposure to these drugs show controversial results. Indomethacin is also used in the postnatal age for pharmacologic treatment of patent ductus arteriosus (PDA), but no data concerning the effects of antenatal exposure on postnatal ductal patency are available.Methods: In this study, we focused primarily on the association between antenatal indomethacin (AI) and postnatal patency of ductus arteriosus while our secondary aim was to highlight any possible influence of AI exposure on adverse neonatal outcomes. We performed a retrospective analysis of 241 medical records of newborns born before 33 weeks' gestation and exposed to antenatal tocolysis. Obstetrical data and neonatal outcomes of newborns exposed to AI were compared to those of neonates exposed to other tocolytic drugs. Early ductal closure (EDC) was defined when functional echocardiography performed within 24 hours of life showed a closed duct. Occurrence of intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), respiratory distress syndrome (RDS), chronic lung disease (CLD), necrotizing enterocolitis (NEC), sepsis, and PDA were compared between the groups and the diagnosis of at least one of III-IV grade IVH, PVL, CLD, sepsis, surgical NEC, or death was defined as a severe outcome.Results: The univariate analysis showed that infants in the AI group were at a higher risk of IVH, CLD, RDS, sepsis, and PDA. The incidence of severe outcomes also appeared to be higher in this group, while no effect of AI on PDA was observed. Since we noticed that infants exposed to AI had a lower gestational age and worse clinical conditions at birth when compared to the controls, we considered this as a confounding factor. To overcome this bias, we performed a multivariate analysis that evidenced no significant role of AI on the occurrence of severe outcomes. On the other hand, a possible association was confirmed for all degrees of IVH (OR: 3.16, 95% CI : [1.41; 7.05]) and sepsis (OR: 2.81, 95% CI: [1.24; 6,28]).Conclusions: The unexpected result shown by the multivariate analysis was the association between AI exposure and EDC (OR: 2.52, 95% CI: [1.02; 6.21]). This result, which has never been evidenced in previous studies, has great clinical importance. It is well known that PDA is more frequent at lower gestational ages, thus reducing the incidence of PDA could lead to an improvement of overall outcomes in extremely preterm newborns.

Fetal anhydramnios following maternal non-steroidal anti-inflammatory drug use in pregnancy

We present a case report of transient fetal anhydramnios following maternal non-steroidal anti-inflammatory drug use in pregnancy. This reduction in liquor volume resolved following cessation of the medication with no obvious ill-effect on neonatal outcome. The case report is followed by a comprehensive summary of the relevant literature.

The Pharmacology of Indomethacin

BACKGROUND

Over 50 years ago, indomethacin emerged as an extremely potent non-steroidal anti-inflammatory drug (NSAID) during a massive effort to find effective anti-inflammatory and analgesic medications. The 1960s saw acetic acid derivatives developed into indomethacin, diclofenac, and sulindac, and propionic derivatives into ibuprofen, naproxen, and ketoprofen. Indomethacin was likely the most potent of these compounds and one of the earliest to enter clinical trials. It is not surprising that indomethacin was among the first of the NSAID medications to be used in treatment of migraine and for headaches that eventually became known as "indomethacin-responsive" headache disorders. Potential pharmacokinetic and bio-mechanistic differences between indomethacin and other NSAIDs are of great clinical and research interest to explain this observation.

METHODS/RESULTS

The present article summarizes pharmacologic properties of indomethacin, including pharmacokinetics with particular attention to its distribution into the central nervous system, adverse effects, drug interactions, and mechanisms of action. Data are emphasized where differences in biomechanisms are found between indomethacin and other NSAIDs. The use of indomethacin in pregnant and lactating women is reviewed.

CONCLUSIONS

NSAIDs easily enter the brain, but their high protein binding limits absolute amount of entry. All work similarly as either nonselective or selective cyclooxygenase inhibitors, but indomethacin may have more potent vasoconstrictive activity and unique direct neuronal or nitric oxide-dependent inhibitory pathway activity.

[A review on tocolysis]

Tocolytic agents have limited efficacy, delaying preterm delivery by 48 hours to 7 days, without any neonatal benefit. Cyclo-oxygenase inhibitors and calcium canal inhibitors seem to be the most efficient. Betamimetics are tocolytic agents with the highest incidence of severe maternal side effects. Oxytocin receptors antagonists and cyclo-oxygenase inhibitors are tocolytic agents with the best maternal tolerating profile. Nifedipin is the tocolytic agent presenting the best fetal tolerating profile. However, doubts persist on fetal and neonatal tolerance for cyclo-oxygenase inhibitors and probably even for oxytocin receptors antagonists. A combined or sequential tocolytic treatment did not prove superior to a single tocolytic treatment although the former is also associated with a high incidence of severe adverse maternal effects. Nevertheless, this low efficiency should not make us forget their major interest in case of premature labour: to allow the mother's in utero transfer to a level II or III maternity following the gestational age, and moreover to gain time so as to obtain an optimal interval for the fetal lung maturation by corticoid injection. Tocolytic agents should be used between 24(+0) and 34(+6)weeks of amenorrhea. They should be used on the short term (24 to 72 hours) owing to their short period of efficacy and to the risk of side effects that increases with the duration of use.

Antenatal exposure to indomethacin increases the risk of severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leukomalacia: a systematic review with metaanalysis

OBJECTIVE

The purpose of this study was to provide an updated summary of the literature regarding the effects of tocolysis with indomethacin on neonatal outcome by systematically reviewing previously and recently reported data.

STUDY DESIGN

All previously reported studies pertaining to indomethacin tocolysis and neonatal outcomes along with recently reported data were identified with the use of electronic databases that had been supplemented with references that were cited in original studies and review articles. Observational studies that compared neonatal outcomes among preterm infants who were exposed and not exposed to indomethacin were included in this systematic review. Data were extracted and quantitative analyses were performed on those studies that assessed the neonatal outcomes of patients that received antenatal tocolysis with indomethacin.

RESULTS

Twenty-seven observational studies that met criteria for systematic review and metaanalysis were identified. These studies included 8454 infants, of whom 1731 were exposed to antenatal indomethacin and 6723 were not exposed. Relative risks with 95% confidence intervals were calculated for dichotomous outcomes with the use of random and fixed-effects models. Metaanalysis revealed no statistically significant differences in the rates of respiratory distress syndrome, patent ductus arteriosus, neonatal mortality rate, neonatal sepsis, bronchopulmonary dysplasia, or intraventricular hemorrhage (all grades). However, antenatal exposure to indomethacin was associated with an increased risk of severe intraventricular hemorrhage (grade III-IV based on Papile's criteria; relative risk, 1.29; 95% confidence interval, 1.06-1.56), necrotizing enterocolitis (relative risk, 1.36; 95% confidence interval, 1.08-1.71), and periventricular leukomalacia (relative risk, 1.59; 95% confidence interval, 1.17-2.17).

CONCLUSION

The use of indomethacin as a tocolytic agent for preterm labor is associated with an increased risk for severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leukomalacia.

Blood reflects tissue oxidative stress: a systematic review

We examined whether the levels of oxidative stress biomarkers measured in blood reflect the tissue redox status. Data from studies that measured redox biomarkers in blood, heart, liver, kidney and skeletal muscle were analyzed. In seven out of nine investigated redox biomarkers (malondialdehyde, reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase, vitamin C and E) there was generally good qualitative and quantitative agreement between the blood and tissues. In contrast, oxidized glutathione and the reduced to oxidized glutathione ratio showed poor agreement between the blood and tissues. This study suggests that most redox biomarkers measured in blood adequately reflect tissue redox status.

Antenatal exposure to sulindac and risk of necrotizing enterocolitis

OBJECTIVE

Most studies of tocolytics are underpowered to assess drug effects on rare adverse neonatal outcomes. Our aim was to optimize statistical power to assess the influence of sulindac on the rare but severe outcome of necrotizing enterocolitis (NEC) by performing a case-control study.

STUDY DESIGN

A priori sample size of 78 in each group was estimated to detect a 2.5-fold increase in nonsteroidal antiinflammatory drug exposure in NEC cases. Maternal-neonatal charts were reviewed from 2007 through 2012 to yield 110 NEC cases: 68 patients with confirmed NEC by Bell's stage II criteria, and 42 with suspected NEC. Cases and controls (N = 131, matched according to gestational age at delivery, plurality, and delivery date) were compared in rates of antenatal exposures to nonsteroidal antiinflammatory drugs, other tocolytics, and maternal-neonatal characteristics and complications.

RESULTS

Cases and controls were delivered at a mean of 28 weeks. Approximately 52% of the total cohort received tocolytics (26% indomethacin, 15% sulindac, 32% calcium channel blockers, 32% beta-sympathomimetics), with no differences in frequency of use between cases and controls. While there was no difference in indomethacin exposure between cases and controls, antenatal exposure to sulindac was independently associated with increased risk of NEC (adjusted odds ratio, 5.33; 95% confidence interval, 1.38-20.57; P = .02), even after adjustment for other factors significantly associated with NEC.

CONCLUSION

Our data demonstrate an adverse association of sulindac with NEC. These findings deserve further investigation and using sulindac as a tocolytic agent requires caution.

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.

Comparison of pooled risk estimates for adverse effects from different observational study designs: methodological overview

BACKGROUND

A diverse range of study designs (e.g. case-control or cohort) are used in the evaluation of adverse effects. We aimed to ascertain whether the risk estimates from meta-analyses of case-control studies differ from that of other study designs.

METHODS

Searches were carried out in 10 databases in addition to reference checking, contacting experts, and handsearching key journals and conference proceedings. Studies were included where a pooled relative measure of an adverse effect (odds ratio or risk ratio) from case-control studies could be directly compared with the pooled estimate for the same adverse effect arising from other types of observational studies.

RESULTS

We included 82 meta-analyses. Pooled estimates of harm from the different study designs had 95% confidence intervals that overlapped in 78/82 instances (95%). Of the 23 cases of discrepant findings (significant harm identified in meta-analysis of one type of study design, but not with the other study design), 16 (70%) stemmed from significantly elevated pooled estimates from case-control studies. There was associated evidence of funnel plot asymmetry consistent with higher risk estimates from case-control studies. On average, cohort or cross-sectional studies yielded pooled odds ratios 0.94 (95% CI 0.88-1.00) times lower than that from case-control studies.

INTERPRETATION

Empirical evidence from this overview indicates that meta-analysis of case-control studies tend to give slightly higher estimates of harm as compared to meta-analyses of other observational studies. However it is impossible to rule out potential confounding from differences in drug dose, duration and populations when comparing between study designs.

Cyclo-oxygenase (COX) inhibitors for preventing preterm labour

BACKGROUND

Preventing preterm labour is the most important step in preventing preterm birth. Prostaglandins play an important role in labour and birth. Prostaglandin production can be obstructed by inhibition of the cyclo-oxygenase (COX) enzyme and this may arrest uterine contraction. A Cochrane review on COX inhibitors for the treatment of preterm labour found insufficient data to draw conclusions about its effectiveness.

OBJECTIVES

To assess the effectiveness and safety of COX inhibitors for preventing preterm labour in high-risk women.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trial Register (30 June 2012).

SELECTION CRITERIA

All published and unpublished randomised trials evaluating administration of any COX inhibitor for prevention of preterm labour in pregnant women at gestational age less than 36 weeks at risk of, but not experiencing, preterm labour. Cluster-randomised trials were eligible for inclusion. Quasi-randomised trials and studies with cross-over designs were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors (T Khanprakob and U Sangkomkamhang) independently assessed all potential studies for inclusion. Disagreement was resolved by discussion and, where necessary, by consultation with a third review author. Two review authors independently assessed trial quality and extracted data. Data were checked for accuracy.

MAIN RESULTS

We included one randomised trial (involving 98 women) that evaluated the effectiveness of one type of COX inhibitor (rofecoxib) for preventing preterm birth. The included study did not report any data for one of our primary outcomes: preterm labour. Rofecoxib use was associated with an increased risk for preterm birth and preterm premature rupture of membranes (PPROM). Rofecoxib was associated with a higher risk of oligohydramnios and low fetal urine production but the effects were reversible after stopping treatment. There were no differences in the number of women who discontinued treatment before 32 weeks of gestation. There was no difference in neonatal morbidities and admission to neonatal intensive care unit. There were no maternal adverse effects or perinatal mortalities in either group.

AUTHORS' CONCLUSIONS

There was very little evidence about using COX inhibitors for preventing preterm labour. There are inadequate data to make any recommendation about using COX inhibitor in practice to prevent preterm labour. Future research should include follow-up of the babies to examine the short-term and long-term effects of COX inhibitors.

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.

Idiopathic constriction of the fetal ductus arteriosus: three cases and review of the literature

Premature constriction or closure of the ductus arteriosus can occur during fetal life. It is a rare phenomenon and has been described secondary to medication or structural lesions or as idiopathic constriction. Premature closure of the ductus arteriosus can lead to progressive right heart dysfunction with tricuspid regurgitation, congestive heart failure, fetal hydrops, and intrauterine death. This series describes diagnosis of fetal ductus arteriosus constriction of unknown etiology in 3 cases, prenatal management, and outcomes. Constriction of the ductus arteriosus can be diagnosed prenatally with careful interrogation of the ductal arch using pulsed Doppler sonography and complete fetal echocardiography. Close monitoring is mandatory to rule out development of right heart failure and to determine the intervention time.

The ductus arteriosus: a refined approach!

Although ongoing patency of the ductus arteriosus is common in small extremely preterm infants, consensus is lacking regarding its clinical significance and treatment strategies. Literature regarding likelihood of spontaneous closure, impact on neonatal morbidity and long-term outcomes, and adverse effects of intervention has led to uncertainty as to the best course of action. Enhancing the determination of hemodynamic significance and refining patient selection for therapeutic intervention will streamline the decision-making process. Targeted neonatal echocardiography performed by the clinician has gained popularity worldwide, and preliminary data show that it has the potential to optimize patient outcomes. We review the arguments for and against medical and surgical therapy, explore how targeted neonatal echocardiography used in conjunction with biomarkers may refine the treatment approach, and consider future directions in the field.

Tocolytic therapy for acute preterm labor

The pathophysiology leading to preterm labor is not well understood and often multifactorial; initiating factors include intrauterine infection, inflammation, ischemia, overdistension, and hemorrhage. Given these different potential causes, directing therapy for preterm labor has been difficult and suboptimal. To date, no single drug has been identified as successful in treating all of the underlying mechanisms leading to preterm labor. In addition, the methodology of many of the tocolytic studies is limited by lack of sufficient patient numbers, lack of comparison with a placebo, and inconsistent use of glucocorticoids. The limitations in these individual studies make it difficult to evaluate the efficacy of a single tocolytic by meta-analysis. Despite these limitations, the goals for tocolysis for preterm labor are clear: To complete a course of glucocorticoids and secure the appropriate level of neonatal care for the fetus in the event of preterm delivery. The literature demonstrates that many tocolytic agents inhibit uterine contractility. The decision as to which tocolytic agent should be used as first-line therapy for a patient is based on multiple factors, including gestational age, the patient’s medical history, common and severe side effects, and a patient’s response to therapy. In a patient at less than 32 weeks gestation, indomethacin may be a reasonable first choice based on its efficacy, ease of administration, and minimal side effects. Concurrent administration of magnesium for neuroprotection may be given. At 32 to 34 weeks, nifedipine may be a reasonable first choice because it does not carry the fetal risks of indomethacin at these later gestational ages, is easy to administer, and has limited side effects relative to beta-mimetics. In an effort to review a commonly faced obstetrical complication, this article has provided a summary of the most commonly used tocolytics, their mechanisms of action, side effects, and clinical data regarding their efficacy.

SOGC Clinical Practice Guideline. Ultrasonographic cervical length assessment in predicting preterm birth in singleton pregnancies

OBJECTIVES

To review (1) the use of ultrasonographic-derived cervical length measurement in predicting preterm birth and (2) interventions associated with a short cervical length.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

EVIDENCE

Published literature was retrieved through searches of PubMed and The Cochrane Library up to December 2009, using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, incompetent cervix, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee and the Maternal Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made according to the guidelines developed by The Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the ultrasonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth.

SPONSORS

The Society of Obstetricians and Gynaecologists of Canada.

Clinical management of the short cervix

Cervical cerclage is associated with prolongation of gestation in singleton pregnancies with prior spontaneous preterm delivery and a short cervix on vaginal ultrasonography in the mid-trimester. Ultrasound screening of cervical length is not indicated in low-risk singleton pregnancies and in women with multiple gestations. 17α-Hydroxyprogesterone does not prevent preterm delivery in twin gestations with a short cervix. Cervical cerclage may cause detrimental effects in twin gestations. Vaginal pessary for the prevention of preterm birth in women with a short cervix is currently under active investigation.

The risk of necrotizing enterocolitis after indomethacin tocolysis

BACKGROUND

Postnatal indomethacin is reportedly associated with an increased incidence of necrotizing enterocolitis (NEC) in preterm infants. Because indomethacin readily crosses the placenta, we hypothesized that antenatal indomethacin (AI) would increase the risk for NEC in preterm infants.

OBJECTIVE

The goal of this study was to explore the association between AI and NEC in preterm infants.

METHODS

Medical records of preterm infants, 23 to 32 weeks' gestational age, without major congenital anomalies, were reviewed. Maternal and neonatal data were abstracted. Association of AI within 15 days before delivery (predictor variable) and classification of NEC according to modified Bell's stage 2a or higher in the first 15 days after delivery (early NEC [primary outcome variable]) was explored by using bivariate analyses, multivariate logistic regression, and propensity score analysis.

RESULTS

Of 628 eligible infants, 63 received AI and 28 developed early NEC. AI exposure was significantly associated with multiple gestation, race, antenatal corticosteroids and magnesium sulfate, lower birth weight and gestational age, umbilical arterial catheter placement, respiratory distress syndrome, postnatal vasopressors and antibiotics, patent ductus arteriosus, sepsis, NEC, intraventricular hemorrhage, and mortality. On multivariate logistic regression controlling for covariates, AI was significantly associated with early NEC (adjusted odds ratio: 7.193 [95% confidence interval: 2.514-20.575]; number needed to harm: 5). The results remained significant when analyses were repeated using AI exposure within 5 days before delivery as a predictor variable; on analyses stratified according to gestational age; and on propensity score analysis.

CONCLUSIONS

AI was associated with NEC in preterm infants in the first 15 days of life in this study, as were multiple other clinical factors.

Meta-analyses of adverse effects data derived from randomised controlled trials as compared to observational studies: methodological overview

BACKGROUND

There is considerable debate as to the relative merits of using randomised controlled trial (RCT) data as opposed to observational data in systematic reviews of adverse effects. This meta-analysis of meta-analyses aimed to assess the level of agreement or disagreement in the estimates of harm derived from meta-analysis of RCTs as compared to meta-analysis of observational studies.

METHODS AND FINDINGS

Searches were carried out in ten databases in addition to reference checking, contacting experts, citation searches, and hand-searching key journals, conference proceedings, and Web sites. Studies were included where a pooled relative measure of an adverse effect (odds ratio or risk ratio) from RCTs could be directly compared, using the ratio of odds ratios, with the pooled estimate for the same adverse effect arising from observational studies. Nineteen studies, yielding 58 meta-analyses, were identified for inclusion. The pooled ratio of odds ratios of RCTs compared to observational studies was estimated to be 1.03 (95% confidence interval 0.93-1.15). There was less discrepancy with larger studies. The symmetric funnel plot suggests that there is no consistent difference between risk estimates from meta-analysis of RCT data and those from meta-analysis of observational studies. In almost all instances, the estimates of harm from meta-analyses of the different study designs had 95% confidence intervals that overlapped (54/58, 93%). In terms of statistical significance, in nearly two-thirds (37/58, 64%), the results agreed (both studies showing a significant increase or significant decrease or both showing no significant difference). In only one meta-analysis about one adverse effect was there opposing statistical significance.

CONCLUSIONS

Empirical evidence from this overview indicates that there is no difference on average in the risk estimate of adverse effects of an intervention derived from meta-analyses of RCTs and meta-analyses of observational studies. This suggests that systematic reviews of adverse effects should not be restricted to specific study types. Please see later in the article for the Editors' Summary.

Comparison of the efficacy and adverse effects of nifedipine and indomethacin for the treatment of preterm labor

OBJECTIVE

To compare the effectiveness and adverse effects of nifedipine versus indomethacin in the treatment of preterm labor.

METHODS

In a randomized clinical trial, 79 women with labor pain at 26-33 weeks of gestation were treated with either oral nifedipine (n=40) or rectal indomethacin (n=39).

RESULTS

Twenty-three (59%) women in the indomethacin group, and 10 (25%) in the nifedipine group did not respond to treatment (P=0.002). None of the 16 and 30 women remaining in the indomethacin and nifedipine groups, respectively, delivered during the subsequent 48 hours. Of these remaining women, 1 (6.25%) in the indomethacin group and 4 (13.3%) in the nifedipine group delivered between 48 hours and 7 days (P=0.162). For the women who responded to treatment, the mean gestational age at time of delivery was 238.5±19.4 days and 246.4±15.4 days in the nifedipine and indomethacin groups, respectively (P=0.182). Seventeen (42.5%) women in the nifedipine group, and 11 (28.2%) in the indomethacin group showed adverse effects (P=0.184).

CONCLUSION

Indomethacin was less effective than nifedipine for the fast treatment of preterm labor. For women who responded to treatment within 2 hours, however, the delaying of delivery by indomethacin was similar to that by nifedipine.

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.

[Indometacin: come back of a controversial tocolytic? Obstetrical point of view]

The main aim of tocolysis is to improve the health of newborns. Given the modest impact in terms of perinatal health of tocolysis we must emphasize the use of tocolytics which, equally effective, have fewer maternal side effects than beta-agonists and are devoid of potential complications for mother and the newborn. Inhibitors of prostaglandin synthesis and calcium antagonists of oxytocin seem to meet these criteria. The recent papers for the use of NSAIDs provide no fundamentally new scientific data. This therapy is potentially associated with severe neonatal complications and superiority to calcium channel blockers or antagonists of oxytocin in terms of prolongation of pregnancy is not established. It seems reasonable to reserve them for special situations by their severity, precocity of the age of gestation or by the ineffectiveness of other treatments. In practice, it is recommended not to use NSAIDs first line, beyond 32 weeks and treatment should be of short duration (less than 48 to 72 hours). Ideally, delivery should not occur within 48 hours after stopping treatment.

Prematurity prevention: the role of acute tocolysis

PURPOSE OF REVIEW

The preterm birth rate in the United States remains at an all-time high and continues to rise. Acute tocolysis has potential to delay preterm birth for 48 h, the critical period of antenatal steroid administration, or to arrest an episode of preterm labor, thus delaying birth and improving neonatal outcomes. It is therefore paramount that medical providers remain up-to-date regarding the usefulness, indications and contraindications, and side-effects and adverse effects of all tocolytics.

RECENT FINDINGS

Magnesium sulfate remains the most common tocolyic agent in the United States. Recent evidence comparing oral nifedipine with magnesium sulfate suggests equal efficacy with fewer maternal side-effects, thus supporting this oral medication as first-line treatment. This review will summarize the most common acute tocolytic drugs, their methods of action, and clinical data regarding their utility.

SUMMARY

All tocolytic medications have side-effects, some of them potentially life-threatening. Decisions regarding whether to use a tocolytic and which tocolytic to use require the diagnosis of preterm labor, knowledge of the patient's gestational age, medical conditions, and cost. Once tocolysis is initiated, attention must be paid to the patient's response, side-effects, and adverse events. Larger studies are needed which incorporate, in addition to efficacy, data on safety and side-effect profiles and cost.

Reversible ductus arteriosus constriction due to maternal indomethacin after fetal intervention for hypoplastic left heart syndrome with intact/restrictive atrial septum

OBJECTIVE

Fetal cardiac intervention (FCI) has been performed at our center in selected fetuses with complex congenital heart disease since 2000. Most interventions are performed in fetuses with a ductus arteriosus (DA)-dependent circulation. Indomethacin promotes closure of the DA in newborns and in fetal life, a potentially life threatening complication in fetuses with ductus-dependent congenital heart disease.

METHODS

We reviewed our experience with FCI with a focus on the frequency, features, and clinical course of ductal constriction. Fetuses undergoing FCI receive comprehensive pre- and postoperative cardiac and cerebral ultrasound evaluation, approximately 24 hours before and after the procedure, including imaging of DA flow and Doppler assessment of the umbilical artery and vein, ductus venosus, and, since 2004, the middle cerebral artery.

RESULTS

Among 113 fetuses that underwent FCI, 24 of which were older than 28 0/7 weeks gestation, 2 were found to have DA constriction due to indomethacin therapy within 24 hours of intervention. Both of these were 30-week fetuses with hypoplastic left heart syndrome and restrictive or intact atrial septum. The DA was stenotic by spectral and color Doppler, and middle cerebral and umbilical artery pulsatility indexes were depressed. After discontinuation of indomethacin, the Doppler indices improved or normalized.

CONCLUSION

Close echocardiographic monitoring of fetal Doppler flow velocities is very important after fetal intervention and indomethacin treatment, as the consequences of DA constriction in a fetus with hypoplastic left heart syndrome are potentially lethal. Sonographic evaluation should include measurement of cerebral and umbilical arterial flow velocities as well as color and spectral Doppler interrogation of the DA.