Indomethacin tocolysis and intraventricular hemorrhage

Diseases and conditions that impact maternal and fetal health and the potential for nanomedicine therapies

Maternal mortality rates in the United States have steadily increased since 1987 to the current rate of over 16 deaths per 100,000 live births. Whereas most of these deaths are related to an underlying condition, such as cardiovascular disease, many pregnant women die from diseases that emerge as a consequence of pregnancy. Both pre-existing and emergent diseases and conditions are difficult to treat in pregnant women because of the potential harmful effects of the treatment on the developing fetus. Often the health of the woman and the health of the baby are at odds and must be weighed against each other when medical treatment is needed, frequently leading to iatrogenic preterm birth. However, the use of engineered nanomedicines has the potential to fill the treatment gap for pregnant women. This review describes several conditions that may afflict pregnant women and fetuses and introduces how engineered nanomedicines may be used to treat these illnesses. Although the field of maternal-fetal nanomedicine is in its infancy, with additional research and development, engineered nanotherapeutics may greatly improve outcomes for pregnant women and their offspring in the future.

Surface-Functionalized Nanoparticles as Efficient Tools in Targeted Therapy of Pregnancy Complications

Minimizing exposure of the fetus to medication and reducing adverse off-target effects in the mother are the primary challenges in developing novel drugs to treat pregnancy complications. Nanomedicine has introduced opportunities for the development of novel platforms enabling targeted delivery of drugs in pregnancy. This review sets out to discuss the advances and potential of surface-functionalized nanoparticles in the targeted therapy of pregnancy complications. We first describe the human placental anatomy, which is fundamental for developing placenta-targeted therapy, and then we review current knowledge of nanoparticle transplacental transport mechanisms. Meanwhile, recent surface-functionalized nanoparticles for targeting the uterus and placenta are examined. Indeed, surface-functionalized nanoparticles could help prevent transplacental passage and promote placental-specific drug delivery, thereby enhancing efficacy and improving safety. We have achieved promising results in targeting the placenta via placental chondroitin sulfate A (plCSA), which is exclusively expressed in the placenta, using plCSA binding peptide (plCSA-BP)-decorated nanoparticles. Others have also focused on using placenta- and uterus-enriched molecules as targets to deliver therapeutics via surface-functionalized nanoparticles. Additionally, we propose that placenta-specific exosomes and surface-modified exosomes might be potential tools in the targeted therapy of pregnancy complications. Altogether, surface-functionalized nanoparticles have great potential value as clinical tools in the targeted therapy of pregnancy complications.

Chorioamnionitis Is a Risk Factor for Intraventricular Hemorrhage in Preterm Infants: A Systematic Review and Meta-Analysis

Although chorioamnionitis (CA) is a well-known risk factor for white matter disease of prematurity, the association with intraventricular hemorrhage (IVH) is controversial and has not been yet systematically reviewed. We performed a systematic review and meta-analysis of studies exploring the association between CA and IVH. A comprehensive literature search was conducted using PubMed/MEDLINE and EMBASE, from their inception to 1 July 2017. Studies were included if they examined preterm infants and reported primary data that could be used to measure the association between exposure to CA and the presence of IVH. A random-effects model was used to calculate odds ratios (OR) and 95% confidence intervals (CI). We found 1,284 potentially relevant studies, of which 85 met the inclusion criteria (46,244 infants, 13,432 CA cases). Meta-analysis showed that CA exposure was significantly associated with all grades IVH (OR 1.88, 95% CI 1.61-2.19), with grades 1-2 IVH (OR 1.69, 95% CI 1.22-2.34), and with grades 3-4 IVH (OR 1.62, 95% CI 1.42-1.85). Both clinical and histological CA were associated with an increased risk for developing IVH in very preterm infants. In contrast, the presence of funisitis did not increase IVH risk when compared to CA in the absence of funisitis (OR 1.22, 95% CI 0.89-1.67). Further meta-analyses confirmed earlier findings that CA-exposed infants have significantly lower gestational age (GA; mean difference [MD] -1.20 weeks) and lower birth weight (BW; MD -55 g) than the infants not exposed to CA. However, meta-regression and subgroup analysis could not demonstrate an association between the lower GA and BW and the risk of IVH in the CA-exposed infants. In conclusion, our data show that CA is a risk factor for IVH, but also a risk factor for greater prematurity and more clinical instability. In contrast to other complications of prematurity, such as patent ductus arteriosus, retinopathy of prematurity, or bronchopulmonary dysplasia, the effect of CA on IVH appears to be independent of CA as causative factor for very preterm birth.

Uterus-targeted liposomes for preterm labor management: studies in pregnant mice

Preterm labor caused by uterine contractions is a major contributor to neonatal morbidity and mortality. Treatment intended to reduce uterine contractions include tocolytic agents, such as indomethacin. Unfortunately, clinically used tocolytics are frequently inefficient and cross the placenta causing fetal side effects. Here we show for the first time in obstetrics the use of a targeted nanoparticle directed to the pregnant uterus and loaded with a tocolytic for reducing its placental passage and sustaining its efficacy. Nanoliposomes encapsulating indomethacin and decorated with clinically used oxytocin receptor antagonist were designed and evaluated in-vitro, ex-vivo and in-vivo. The proposed approach resulted in targeting uterine cells in-vitro, inhibiting uterine contractions ex-vivo, while doubling uterine drug concentration, decreasing fetal levels, and maintaining the preterm birth rate in vivo in a pregnant mouse model. This promising approach opens new horizons for drug development in obstetrics that could greatly impact preterm birth, which currently has no successful treatments.

Humanized mice, a new model to study the influence of drug treatment on neonatal sepsis

Bacterial infection with group B Streptococcus (GBS) represents a prominent threat to neonates and fetuses in the Western world, causing severe organ damage and even death. To improve current therapeutic strategies and to investigate new approaches, an appropriate in vivo model to study the immune response of a human immune system is needed. Therefore, we introduced humanized mice as a new model for GBS-induced sepsis. Humanized mice feature deficiencies similar to those found in neonates, such as lower immunoglobulin levels and myeloid cell dysfunction. Due to the husbandry in specific-pathogen-free (SPF) facilities, the human immune cells in these mice also exhibit a naive phenotype which mimics the conditions in fetuses/neonates. Following infection, cytokine release and leukocyte trafficking from the bone marrow to the lymphoid organ (spleen) and into the peritoneum (site of infection) as well as bacterial spreading and clearance were traceable in the humanized mice. Furthermore, we investigated the effects of betamethasone and indomethacin treatment using this novel sepsis model. Although both drugs are commonly used in perinatal care, little is known about their effects on the neonatal immune system. Treatment of infected humanized mice not only induced the reduction of human leukocytes in the spleen but also increased the bacterial load in all analyzed organs, including the brain, which did not show infiltration of live GBS in untreated controls. These studies demonstrate the utility of the humanized mice as a new model to study an immature human immune response during bacterial infection and allow the investigation of side effects induced by various treatments.

Goals and strategies for prevention of preterm birth: an obstetric perspective

Complications of prematurity surpass congenital malformations as the leading cause of infant mortality in the United States. Since 1990, there has been a steady rise in preterm birth, alarming health professionals from all disciplines. This review from a prenatal perspective confirms those concerns and describes the risks and opportunities that may attend efforts to improve the health of fetuses, newborns, and infants. Fetal and live-born outcomes are included.

Metaanalysis of the effect of antenatal indomethacin on neonatal outcomes

OBJECTIVE

The objective of the study was to determine whether indomethacin used as a tocolytic agent is associated with adverse neonatal outcomes.

STUDY DESIGN

We used published guidelines of the Metaanalysis of Observational Studies in Epidemiology Group (MOOSE) to perform the metaanalysis. The search strategy used included computerized bibliographic searches of MEDLINE (1966-2005), PubMed (1966-2005), abstracts published in Obstetrics and Gynecology (1991-2005), abstracts published in Pediatric Research (1991-2005), and references of published manuscripts. Study inclusion criteria were publication in English, more than 30 deliveries less than 37 weeks' gestation, and meeting diagnostic criteria for individual neonatal outcomes. Exclusion criteria included case reports, case series, and multiple publications from the same author. Metaanalysis was performed using random effects model if there were more than 2 observational studies for a specific outcome. Eggers test was performed to exclude publication bias. Sensitivity analysis was performed to evaluate the effect of antenatal steroid exposure, gestation, and recent antenatal indomethacin exposure (duration of 48 hours or more between the last dose and delivery).

RESULTS

Fifteen retrospective cohort studies and 6 case-controlled studies met inclusion criteria. Antenatal indomethacin was associated with an increased risk of periventricular leukomalacia (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.3-3.1). Recent exposure to antenatal indomethacin was associated with necrotizing enterocolitis (OR, 2.2; 95% CI; 1.1-4.2). Antenatal indomethacin was not associated with intraventricular hemorrhage, patent ductus arteriosus, respiratory distress syndrome, bronchopulmonary dysplasia, and mortality.

CONCLUSION

Antenatal indomethacin may be associated with an increased risk of periventricular leukomalacia and necrotizing enterocolitis in premature infants and therefore should be used judiciously for tocolysis.

Assessing the Neonatal Safety of Indomethacin Tocolysis

OBJECTIVE

To systematically review and summarize the medical literature regarding the effects of tocolysis with indomethacin on neonatal outcome.

DATA SOURCES

We supplemented a search of entries in electronic databases with references cited in original studies and review articles to identify studies pertaining to indomethacin tocolysis and neonatal outcome.

METHODS OF STUDY SELECTION

We evaluated, abstracted data, and performed quantitative analyses in studies assessing the neonatal outcomes of patients undergoing tocolysis with indomethacin. Observational studies and randomized trials were included in this systematic review.

TABULATION, INTEGRATION, AND RESULTS

Forty-six studies were identified, 28 of which met criteria for systematic review and meta-analysis. These 28 studies included 6,008 infants. Of these infants, 1,621 were exposed to indomethacin for tocolysis antenatally; 4,387 infants not exposed to indomethacin served as the comparison group. An estimate of pooled odds ratios with 95% confidence intervals was calculated for dichotomous outcomes using random- and fixed-effects models. Observational studies and randomized trials were analyzed separately. Pooled estimates from observational studies and randomized trials revealed no significant differences in the rates of intraventricular hemorrhage, patent ductus arteriosus, necrotizing enterocolitis, or neonatal mortality between infants exposed to indomethacin antenatally and those not exposed. Meta-analysis of randomized trials revealed increased risk of bronchopulmonary dysplasia. However, the meta-analysis included only 3 randomized clinical trials, one of which showed increased risk. An association of bronchopulmonary dysplasia and indomethacin use was not noted in our analysis of observational studies.

CONCLUSION

Although our pooled results did not identify significantly increased risks of adverse effects, the limited statistical power of published randomized trials does not allow us to exclude the possibility that indomethacin tocolysis increases the risk of adverse neonatal outcomes.

The effect of short-term indomethacin therapy on amniotic fluid volume

OBJECTIVE

The purpose of this study was to determine the effect of short-term (48 hour) indomethacin therapy on amniotic fluid volume.

STUDY DESIGN

Patients who were admitted to Northwestern Memorial Hospital in preterm labor and who received indomethacin tocolysis were eligible for the study. Thirty-five patients with singleton gestations and 26 patients with twin gestations were enrolled. Amniotic fluid volumes were measured at baseline, at 48 hours after the initiation of indomethacin, and then every 24 hours thereafter for a maximum of 7 days.

RESULTS

There were no significant changes in mean amniotic fluid volume subsequent to the administration of indomethacin at any of the time points that were measured. Among the 61 patients who received indomethacin, there were 2 cases of oligohydramnios (3.3%; 95% CI, 0.03%, 11.3%). In both cases, the amniotic fluid index returned to normal within 24 hours after the discontinuation of indomethacin.

CONCLUSION

Short-term indomethacin therapy, in either singleton or twin gestations, does not cause a clinically significant change in amniotic fluid volume.

The Randomized Nitric Oxide Tocolysis Trial (RNOTT) for the treatment of preterm labor

OBJECTIVE

This study was undertaken to assess the effectiveness of glyceryl trinitrate (GTN) patches in comparison with beta2 sympathomimetics (beta2) for the treatment of preterm labor.

STUDY DESIGN

A multicenter, multinational, randomized controlled trial was conducted in tertiary referral teaching hospitals. Women in threatened preterm labor with positive fetal fibronectin or ruptured membranes between 24 and 35 weeks' gestation were recruited and randomly assigned to either beta2 or GTN with rescue beta2 tocolysis if moderate-to-strong contractions persisted at 2 hours. Obstetric and neonatal outcomes were assessed.

RESULTS

Two hundred thirty-eight women were recruited and randomly assigned, 117 to beta2 and 121 to GTN. On a strict intention-to-treat basis, there was no significant difference in the time to delivery using Kaplan-Meier curves (P = .451). At 2 hours, 27% of women receiving beta2 had moderate or stronger contractions compared with 53% in the GTN group (P < .001). This led to 35% of women in the GTN group receiving rescue treatment. If delivery or requirement for beta2 rescue are regarded as treatment failure, then a significant difference was observed between the 2 arms (P = .0032). There were no significant differences in neonatal outcomes.

CONCLUSION

GTN is a less efficacious tocolytic compared with ss2 sympathomimetics.

The neonate with suspected congenital heart disease

Congenital heart disease (CHD) occurs in 8 per 1000 live births, with approximately one third of these neonates requiring intervention in the first month of life. Neonates with respiratory distress, cyanosis, feeding difficulties, low cardiac output, or dysmorphic syndromes commonly have CHD. Clinical suspicion increases in a symptomatic infant with a heart murmur, but the presence or absence of a murmur does not assure either the presence or absence of significant congenital heart disease. Infants suspected to have CHD may be divided into premature and term infants, as well as infants with duct-dependent pulmonary blood flow, infants with duct-dependent systemic blood flow, and infants with unrestricted pulmonary blood flow. This article will also address the specialized clinical situations of total anomalous pulmonary venous return, transposition of the great arteries, and hypoplastic left heart syndrome with intact atrial septum.

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.