A Randomised, Double-Blinded, Placebo-Controlled Study of the Phosphodiesterase Type 5 Inhibitor Sildenafil for the Treatment of Preeclampsia

Neurodevelopmental outcomes at 2 years in children who received sildenafil therapy in utero: The STRIDER randomised controlled trial

OBJECTIVE

Severe early-onset fetal growth restriction (FGR) causes stillbirth, neonatal death and neurodevelopmental impairment. Poor maternal spiral artery remodelling maintains vasoactive responsiveness but is susceptible to treatment with sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, which may improve perinatal outcomes.

DESIGN

Superiority, double-blind randomised controlled trial.

SETTING

A total of 20 UK fetal medicine units.

POPULATION

Pregnancies affected by FGR, defined as an abdominal circumference below the tenth centile with absent end-diastolic flow in the umbilical artery between 22+0 and 29+6 weeks of gestation.

METHODS

Treatment with sildenafil (25 mg three times/day) or placebo until delivery or 32 weeks of gestation.

MAIN OUTCOME MEASURES

All infants alive at hospital discharge were assessed for cardiovascular function and cognitive, speech/language and neuromotor impairment at 2 years of age. The primary outcome was survival without cerebral palsy or neurosensory impairment, or a Bayley-III composite score of >85.

RESULTS

In total, 135 women were randomised between November 2014 and July 2016 (70 to sildenafil and 65 to placebo). We previously published that there was no improvement in time to delivery or perinatal outcomes with sildenafil. In all, 75 babies (55.5%) were discharged alive, with 61 infants eligible for follow-up (32 sildenafil and 29 placebo). One infant died (placebo), three mothers declined and ten mothers were uncontactable. There was no difference in neurodevelopment or blood pressure following treatment with sildenafil. Infants who received sildenafil had a larger head circumference at 2 years of age (median difference 49.2 cm, IQR 46.4-50.3, vs 47.2 cm, 95% CI 44.7-48.9 cm).

CONCLUSIONS

Sildenafil therapy did not prolong pregnancy or improve perinatal outcomes and did not improve infant neurodevelopment in FGR survivors. Therefore, sildenafil should not be prescribed for this condition.

The iSEARCH randomised controlled trial protocol: a pragmatic Australian phase III clinical trial of intrapartum sildenafil citrate to improve outcomes potentially related to intrapartum hypoxia

INTRODUCTION

We showed in a phase II randomised controlled trial (RCT) that oral sildenafil citrate in term labour halved operative birth for fetal distress. We outline the protocol for a phase III RCT (can intrapartum SildEnafil safely Avert the Risks of Contraction-induced Hypoxia? (iSEARCH)) of 3200 women in Australia to assess if sildenafil citrate reduces adverse perinatal outcomes related to intrapartum hypoxia.

METHODS AND ANALYSIS

iSEARCH will enrol 3200 Australian women in term labour to determine whether up to three 50 mg oral doses of sildenafil citrate versus placebo reduce the relative risk of a primary composite end point of 10 perinatal outcomes potentially related to intrapartum hypoxia by 35% (from 7% to 4.55%). Secondary aims are to evaluate reductions in the relative risk of emergency caesarean section or instrumental vaginal birth for fetal distress by 25% (from 20% to 15%) and in healthcare costs. To detect a 35% reduction in the primary outcome for an alpha of 0.05 and power of 80% with 10% dropout in each arm requires 3200 women (1600 in each arm). This sample size will also yield >90% power to detect a 25% reduction for the secondary outcome of any operative birth (caesarean section or instrumental vaginal birth) for fetal distress.

ETHICS AND DISSEMINATION

Ethical approval for the iSEARCH RCT was granted by the Hunter New England Human Research Ethics Committee (ref no: 2020/ETH02791). Results will be disseminated through websites, peer-reviewed publications, scientific meetings and social media, news outlets, television and radio.

TRIAL REGISTRATION NUMBER

ACTRN12621000231842.

Tadalafil for Treatment of Fetal Growth Restriction: A Review of Experimental and Clinical Studies

Fetal growth restriction (FGR) is a major concern in perinatal care. Various medications have been proposed as potential treatments for this serious condition. Nonetheless, there is still no definitive treatment. We studied tadalafil, a phosphodiesterase-5 inhibitor, as a therapeutic agent for FGR in clinical studies and animal experiments. In this review, we summarize our preclinical and clinical data on the use of tadalafil for FGR. Our studies in mouse models indicated that tadalafil improved FGR and hypertensive disorders of pregnancy. A phase II trial we conducted provided evidence supporting the efficacy of tadalafil in prolonging pregnancy (52.4 vs. 36.8 days; p = 0.03) and indicated a good safety profile for fetuses and neonates. Fetal, neonatal, and infant mortality was significantly lower in mothers receiving tadalafil treatment than that in controls (total number: 1 vs. 7, respectively; p = 0.03), and no severe adverse maternal events associated with tadalafil were observed. Although further studies are needed to establish the usefulness of tadalafil in FGR treatment, our research indicates that the use of tadalafil in FGR treatment may be a paradigm shift in perinatal care.

Interventions affecting the nitric oxide pathway versus placebo or no therapy for fetal growth restriction in pregnancy

BACKGROUND

Fetal growth restriction (FGR) is a condition of poor growth of the fetus in utero. One of the causes of FGR is placental insufficiency. Severe early-onset FGR at < 32 weeks of gestation occurs in an estimated 0.4% of pregnancies. This extreme phenotype is associated with a high risk of fetal death, neonatal mortality, and neonatal morbidity. Currently, there is no causal treatment, and management is focused on indicated preterm birth to prevent fetal death. Interest has risen in interventions that aim to improve placental function by administration of pharmacological agents affecting the nitric oxide pathway causing vasodilatation.

OBJECTIVES

The objective of this systematic review and aggregate data meta-analysis is to assess the beneficial and harmful effects of interventions affecting the nitric oxide pathway compared with placebo, no therapy, or different drugs affecting this pathway against each other, in pregnant women with severe early-onset FGR.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (16 July 2022), and reference lists of retrieved studies.

SELECTION CRITERIA

We considered all randomised controlled comparisons of interventions affecting the nitric oxide pathway compared with placebo, no therapy, or another drug affecting this pathway in pregnant women with severe early-onset FGR of placental origin, for inclusion in this review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Pregnancy and Childbirth methods for data collection and analysis.

MAIN RESULTS

We included a total of eight studies (679 women) in this review, all of which contributed to the data and analysis. The identified studies report on five different comparisons: sildenafil compared with placebo or no therapy, tadalafil compared with placebo or no therapy, L-arginine compared with placebo or no therapy, nitroglycerin compared with placebo or no therapy and sildenafil compared with nitroglycerin. The risk of bias of included studies was judged as low or unclear. In two studies the intervention was not blinded. The certainty of evidence for our primary outcomes was judged as moderate for the intervention sildenafil and low for tadalafil and nitroglycerine (due to low number of participants and low number of events). For the intervention L-arginine, our primary outcomes were not reported. Sildenafil citrate compared to placebo or no therapy (5 studies, 516 women) Five studies (Canada, Australia and New Zealand, the Netherlands, the UK and Brazil) involving 516 pregnant women with FGR were included. We assessed the certainty of the evidence as moderate. Compared with placebo or no therapy, sildenafil probably has little or no effect on all-cause mortality (risk ratio (RR) 1.01, 95% confidence interval (CI) 0.80 to 1.27, 5 studies, 516 women); may reduce fetal mortality (RR 0.82, 95% CI 0.60 to 1.12, 5 studies, 516 women), and increase neonatal mortality (RR 1.45, 95% CI 0.90 to 2.33, 5 studies, 397 women), although the results are uncertain for fetal and neonatal mortality as 95% confidence intervals are wide crossing the line of no effect. Tadalafil compared with placebo or no therapy (1 study, 87 women) One study (Japan) involving 87 pregnant women with FGR was included. We assessed the certainty of the evidence as low. Compared with placebo or no therapy, tadalafil may have little or no effect on all-cause mortality (risk ratio 0.20, 95% CI 0.02 to 1.60, one study, 87 women); fetal mortality (RR 0.11, 95% CI 0.01 to 1.96, one study, 87 women); and neonatal mortality (RR 0.89, 95% CI 0.06 to 13.70, one study, 83 women). L-Arginine compared with placebo or no therapy (1 study, 43 women) One study (France) involving 43 pregnant women with FGR was included. This study did not assess our primary outcomes. Nitroglycerin compared to placebo or no therapy (1 studies, 23 women) One study (Brazil) involving 23 pregnant women with FGR was included. We assessed the certainty of the evidence as low. The effect on the primary outcomes is not estimable due to no events in women participating in both groups. Sildenafil citrate compared to nitroglycerin (1 study, 23 women) One study (Brazil) involving 23 pregnant women with FGR was included. We assessed the certainty of the evidence as low. The effect on the primary outcomes is not estimable due to no events in women participating in both groups.

AUTHORS' CONCLUSIONS

Interventions affecting the nitric oxide pathway probably do not seem to influence all-cause (fetal and neonatal) mortality in pregnant women carrying a baby with FGR, although more evidence is needed. The certainty of this evidence is moderate for sildenafil and low for tadalafil and nitroglycerin. For sildenafil a fair amount of data are available from randomised clinical trials, but with low numbers of participants. Therefore, the certainty of evidence is moderate. For the other interventions investigated in this review there are insufficient data, meaning we do not know whether these interventions improve perinatal and maternal outcomes in pregnant women with FGR.

The effects of sildenafil citrate on intrauterine growth restriction: a systematic review and meta-analysis

BACKGROUND

An increase in vascular resistance of uterine vessels is associated with intrauterine growth restriction (IUGR). Sildenafil citrate, a phosphodiesterase-5 inhibitor that stabilizes cyclic guanosine monophosphate (cGMP) and increases nitric oxide levels, improves placental perfusion by dilation of spiral arteries and is beneficial in managing IUGR. This study aims to determine the effectiveness of sildenafil citrate in improving perinatal outcomes in IUGR pregnancies.

METHODS

Meta-analysis was performed on data extracted from all studies specific to sildenafil citrate in IUGR management, searching relevant articles on PubMed, Medline, Google Scholar, Embase, and Cochrane databases. Publications identified by the manual search, based on references in reviews, were also included. Dichotomous results were presented as risk ratio (95% confidence interval), while continuous results were expressed as mean difference (MD); samples represented by the random effects model.

RESULTS

Nine trials were included where the sildenafil citrate effect was compared with a placebo or no intervention. A significant increase in birth weight [SMD (95% CI), 0.69 (0.31, 1.07)] was seen in IUGR pregnancies managed with sildenafil. However, gestational age (SMD (95% CI), 0.44 (-0.05, 0.94], fetal death rate [RR (95% CI), 0.56 (0.17, 1.79)] in IUGR pregnancies was not changed by sildenafil. Neonatal death [RR (95% CI), 0.93 (0.47, 1.86)] and neonatal intensive care unit (NICU) admissions [RR (95% CI), 0.76 (0.50, 1.17)] were not significantly different between sildenafil and control groups.

CONCLUSION

Sildenafil citrate increases birth weight and prolonged pregnancies but did not affect stillbirth rate, neonatal death, and NICU admission.

TRIAL REGISTRATION

The study was registered in PROSPERO on September 18, 2021 (CRD42021271992).

Comprehensive Review of Hypertensive Disorders Related to Pregnancy

Hypertensive disorder of pregnancy is a common complication during pregnancy that affects approximately 10% of pregnancies and is responsible for nearly 14% of maternal deaths worldwide. It affects the mother and the fetus simultaneously, sometimes putting the health of the mother and the fetus at odds with each other. It may present with only hypertension and proteinuria or with life-threatening complications in the mother such as eclampsia; stroke; acute pulmonary edema; acute renal failure; disseminated intravascular coagulation; placental abruption; hemolysis, elevated liver enzymes, and low platelet syndrome; pregnancy loss; and fetal growth restriction and prematurity resulting from the frequent need of delivering preterm in the fetus. In this review, we aimed to describe hypertensive disorders of pregnancy, mainly preeclampsia and chronic hypertension in pregnancy, by discussing the pathophysiology, the central role of abnormal placentation, the release of antiangiogenic factors in the circulation and immunological factors, the clinical outcome in the mother and the fetus, and the diagnostic criteria and principles of management of both the conditions. We also discuss possible screening methods and prevention of preeclampsia using low-dose aspirin and eclampsia prophylaxis.

PBPK-based dose finding for sildenafil in pregnant women for antenatal treatment of congenital diaphragmatic hernia

Sildenafil is a potent vasodilator and phosphodiesterase type five inhibitor, commercially known as Revatio® and approved for the treatment of pulmonary arterial hypertension. Maternal administration of sildenafil during pregnancy is being evaluated for antenatal treatment of several conditions, including the prevention of pulmonary hypertension in fetuses with congenital diaphragmatic hernia. However, determination of a safe and effective maternal dose to achieve adequate fetal exposure to sildenafil remains challenging, as pregnancy almost always is an exclusion criterion in clinical studies. Physiologically-based pharmacokinetic (PBPK) modelling offers an attractive approach for dose finding in this specific population. The aim of this study is to exploit physiologically-based pharmacokinetic modelling to predict the required maternal dose to achieve therapeutic fetal exposure for the treatment congenital diaphragmatic hernia. A full-PBPK model was developed for sildenafil and N-desmethyl-sildenafil using the Simcyp simulator V21 platform, and verified in adult reference individuals, as well as in pregnant women, taking into account maternal and fetal physiology, along with factors known to determine hepatic disposition of sildenafil. Clinical pharmacokinetic data in mother and fetus were previously obtained in the RIDSTRESS study and were used for model verification purposes. Subsequent simulations were performed relying either on measured values for fetal fraction unbound (fu = 0.108) or on values predicted by the simulator (fu = 0.044). Adequate doses were predicted according to the efficacy target of 15 ng/mL (or 38 ng/mL) and safety target of 166 ng/mL (or 409 ng/mL), assuming measured (or predicted) fu values, respectively. Considering simulated median profiles for average steady state sildenafil concentrations, dosing regimens of 130 mg/day or 150 mg/day (administered as t.i.d.), were within the therapeutic window, assuming either measured or predicted fu values, respectively. For safety reasons, dosing should be initiated at 130 mg/day, under therapeutic drug monitoring. Additional experimental measurements should be performed to confirm accurate fetal (and maternal) values for fu. Additional characterization of pharmacodynamics in this specific population is required and may lead to further optimization of the dosing regimen.

Novel therapeutic and diagnostic approaches for preeclampsia

PURPOSE OF REVIEW

This review will summarize recent findings relating to the diagnostic approach to preeclampsia and current avenues of research aimed at modifying the underlying disease process.

RECENT FINDINGS

Growing international consensus supports a broad preeclampsia definition that incorporates maternal end-organ and uteroplacental dysfunction. Recent evidence demonstrates that this definition better identifies women and babies at risk of adverse outcomes compared to the traditional definition of hypertension and proteinuria. Multiple studies have demonstrated the usefulness and cost-effectiveness of angiogenic biomarkers such as soluble fms-like tyrosine kinase-1 and placental growth factor as a clinical adjunct to diagnose and predict severity of preeclampsia associated outcomes. Current novel therapeutic approaches to preeclampsia target pathogenic pathways (e.g. antiangiogenesis) or downstream effects such as oxidative stress and nitric oxide. Recent findings relating to these promising candidates are discussed. Multicenter clinical trials are needed to evaluate their effectiveness and ability to improve fetal and maternal outcomes.

SUMMARY

We provide an updated framework of the current approaches to define and diagnose preeclampsia. Disease modifying therapies (in particular, targeting the angiogenic pathway) are being developed for the first time and promise to revolutionize the way we manage preeclampsia.

A review of ex vivo placental perfusion models: an underutilized but promising method to study maternal-fetal interactions

Studying the placenta can provide information about the mechanistic pathways of pregnancy disease. However, analyzing placental tissues and manipulating placental function in real-time during pregnancy is not feasible. The ex vivo placental perfusion model allows observing important aspects of the physiology and pathology of the placenta, while maintaining its viability and functional integrity, and without causing harm to mother or fetus. In this review, we describe and compare setups for this technically complex model and summarize outcomes from various published studies. We hope that our review will encourage wider use of ex vivo placental perfusion, which in turn would generate more knowledge to improve pregnancy outcomes.

Sildenafil during the 2nd and 3rd Trimester of Pregnancy: Trials and Tribulations

Sildenafil, a phosphodiesterase 5 inhibitor with a vasodilatory and anti-remodeling effect, has been investigated concerning various conditions during pregnancy. Per indication, we herein review the rationale and the most relevant experimental and clinical studies, including systematic reviews and meta-analyses, when available. Indications for using sildenafil during the second and third trimester of pregnancy include maternal pulmonary hypertension, preeclampsia, preterm labor, fetal growth restriction, oligohydramnios, fetal distress, and congenital diaphragmatic hernia. For most indications, the rationale for administering prenatal sildenafil is based on limited, equivocal data from in vitro studies and rodent disease models. Clinical studies report mild maternal side effects and suggest good fetal tolerance and safety depending on the underlying pathology.

Newborn screen metabolic panels reflect the impact of common disorders of pregnancy

BACKGROUND

Hypertensive disorders of pregnancy and maternal diabetes profoundly affect fetal and newborn growth, yet disturbances in intermediate metabolism and relevant mediators of fetal growth alterations remain poorly defined. We sought to determine whether there are distinct newborn screen metabolic patterns among newborns affected by maternal hypertensive disorders or diabetes in utero.

METHODS

A retrospective observational study investigating distinct newborn screen metabolites in conjunction with data linked to birth and hospitalization records in the state of California between 2005 and 2010.

RESULTS

A total of 41,333 maternal-infant dyads were included. Infants of diabetic mothers demonstrated associations with short-chain acylcarnitines and free carnitine. Infants born to mothers with preeclampsia with severe features and chronic hypertension with superimposed preeclampsia had alterations in acetylcarnitine, free carnitine, and ornithine levels. These results were further accentuated by size for gestational age designations.

CONCLUSIONS

Infants of diabetic mothers demonstrate metabolic signs of incomplete beta oxidation and altered lipid metabolism. Infants of mothers with hypertensive disorders of pregnancy carry analyte signals that may reflect oxidative stress via altered nitric oxide signaling. The newborn screen analyte composition is influenced by the presence of these maternal conditions and is further associated with the newborn size designation at birth.

IMPACT

Substantial differences in newborn screen analyte profiles were present based on the presence or absence of maternal diabetes or hypertensive disorder of pregnancy and this finding was further influenced by the newborn size designation at birth. The metabolic health of the newborn can be examined using the newborn screen and is heavily impacted by the condition of the mother during pregnancy. Utilizing the newborn screen to identify newborns affected by common conditions of pregnancy may help relate an infant's underlying biological disposition with their clinical phenotype allowing for greater risk stratification and intervention.

Halting the Canadian STRIDER randomised controlled trial of sildenafil for severe, early-onset fetal growth restriction: ethical, methodological, and pragmatic considerations

Objectives

To determine the efficacy and safety of sildenafil citrate to improve outcomes in pregnancies complicated by early-onset, dismal prognosis, fetal growth restriction (FGR). Eligibility: women ≥ 18 years, singleton, 18 + 0–27 + 6 weeks’ gestation, estimated fetal weight < 700 g, low PLFG, and ≥ 1 of (i) abdominal circumference < 10th percentile for gestational age (GA); or (ii) reduced growth velocity and either abnormal uterine artery Doppler or prior early-onset FGR with adverse outcome. Ineligibility criteria included: planned termination or reversed umbilical artery end-diastolic flow. Eligibility confirmed by placental growth factor (PlGF) < 5 th percentile for GA measured post randomization. Women randomly received (1:1) either sildenafil 25 mg three times daily or matched placebo until either delivery or 31 + 6 weeks. Primary outcome: delivery GA. The trial stopped early when Dutch STRIDER signalled potential harm; despite distinct eligibility criteria and IRB and DSMB support to continue, because of futility. NCT02442492 [registered 13/05/2015].

Results

Between May 2017 and June 2018, 21 (90 planned) women were randomised [10 sildenafil; 11 placebo (1 withdrawal)]. Baseline characteristics, PlGF levels, maternal and perinatal outcomes, and adverse events did not differ. Delivery GA: 26 + 6 weeks (sildenafil) vs 29 + 2 weeks (placebo); p = 0.200. Data will contribute to an individual participant data meta-analysis.

Phosphodiesterase-5 inhibitors in pregnancy: Systematic review and meta-analysis of maternal and perinatal safety and clinical outcomes

BACKGROUND

The efficacy and safety profile of phosphodiesterase-5 inhibitors (PDE-5i) in pregnancy are unclear from the few relatively small diverse studies that have used them.

OBJECTIVE

To assess the safety profile and clinical outcomes of PDE-5i use in pregnancy.

SEARCH STRATEGY

We searched Embase, PubMed, CENTRAL, Prospero and Google Scholar to identify randomised controlled trials (RCTs) reporting the use of any PDE-5i in pregnancy up to September 2021.

SELECTION CRITERIA

RCTs reporting obstetric or perinatal outcomes or maternal adverse outcomes in women taking PDE5i in pregnancy.

DATA COLLECTION AND ANALYSIS

Risk ratios (RR), 95% confidence intervals (95% CI) and 95% prediction intervals were calculated and pooled for analysis.

RESULTS

We identified 1324 citations, of which 10 studies including 1090 participants met the inclusion criteria. Only tadalafil and sildenafil were reported as used in pregnancy. Two studies using tadalafil and eight sildenafil. Nine of ten studies were assessed at having of low risk of bias. PDE-5i use was associated with an increased risk of headaches (RR 1.41, 95% CI 0.97-2.05), flushing (RR 2.59, 95% CI 0.69-9.90) and nasal bleeding (RR 10.53, 95% CI 1.36-81.3); an increase in vaginal birth when used for non-fetal growth restriction (FGR) indications (RR 1.24, 95% CI 1.00-1.55) and a reduction in risk of operative birth for intrapartum fetal compromise (RR 0.58, 95% CI 0.38-0.88). There was no evidence of any increase in risk of perinatal death (RR 0.89, 95% CI 0.56-1.43). However, use for the treatment of FGR increased the risk of persistent pulmonary hypertension of the newborn (PPHN) (RR 2.52, 95% CI 1.00-6.32).

CONCLUSIONS

This meta-analysis suggests PDE-5i use in pregnancy is associated with mild maternal side effects and lower risk of operative birth for intrapartum fetal distress. Prolonged use for the treatment of FGR may increase the risk of PPHN.

Oral Antihypertensives for Nonsevere Pregnancy Hypertension: Systematic Review, Network Meta- and Trial Sequential Analyses

BACKGROUND

We aimed to address which antihypertensives are superior to placebo/no therapy or another antihypertensive for controlling nonsevere pregnancy hypertension and provide future sample size estimates for definitive evidence.

METHODS

Randomized trials of antihypertensives for nonsevere pregnancy hypertension were identified from online electronic databases, to February 28, 2021 (registration URL: https://www.crd.york.ac.uk/PROSPERO/; unique identifier: CRD42020188725). Our outcomes were severe hypertension, proteinuria/preeclampsia, fetal/newborn death, small-for-gestational age infants, preterm birth, and admission to neonatal care. A Bayesian random-effects model generated estimates of direct and indirect treatment comparisons. Trial sequential analysis informed future trials needed.

RESULTS

Of 1246 publications identified, 72 trials were included; 61 (6923 women) were informative. All commonly prescribed antihypertensives (labetalol, other β-blockers, methyldopa, calcium channel blockers, and mixed/multi-drug therapy) versus placebo/no therapy reduced the risk of severe hypertension by 30% to 70%. Labetalol decreased proteinuria/preeclampsia (odds ratio, 0.73 [95% credible interval, 0.54-0.99]) and fetal/newborn death (odds ratio, 0.54 [0.30-0.98]) compared with placebo/no therapy, and proteinuria/preeclampsia compared with methyldopa (odds ratio, 0.66 [0.44-0.99]) and calcium channel blockers (odds ratio, 0.63 [0.41-0.96]). No other differences were identified, but credible intervals were wide. Trial sequential analysis indicated that 2500 to 10 000 women/arm (severe hypertension or safety outcomes) to >15 000/arm (fetal/newborn death) would be required to provide definitive evidence.

CONCLUSIONS

In summary, all commonly prescribed antihypertensives in pregnancy reduce the risk of severe hypertension, but labetalol may also decrease proteinuria/preeclampsia and fetal/newborn death. Evidence is lacking for many other safety outcomes. Prohibitive sample sizes are required for definitive evidence. Real-world data are needed to individualize care.

Reproductive Issues and Pregnancy Implications in Systemic Sclerosis

Systemic sclerosis (SSc) is a rare systemic autoimmune disease that can influence reproductive health. SSc has a strong female predominance, and the disease onset can occur during fertility age in almost 50% of patients. Preconception counseling, adjustment of treatment, and close surveillance during pregnancy by a multidisciplinary team, are key points to minimize fetal and maternal risks and favor successful pregnancy outcomes. The rates of spontaneous pregnancy losses are comparable to those of the general obstetric population, except for patients with diffuse cutaneous SSc and severe internal organ involvement who may carry a higher risk of abortion. Preterm birth can frequently occur in women with SSc, as it happens in other rheumatic diseases. Overall disease activity generally remains stable during pregnancy, but particular attention should be paid to women with major organ disease, such as renal and cardiopulmonary involvement. Women with such severe involvement should be thoroughly informed about the risks during pregnancy and possibly discouraged from getting pregnant. A high frequency of sexual dysfunction has been described among SSc patients, both in females and in males, and pathogenic mechanisms of SSc may play a fundamental role in determining this impairment. Fertility is overall normal in SSc women, while no studies in the literature have investigated fertility in SSc male patients. Nevertheless, some considerations regarding the impact of some immunosuppressive drugs should be done with male patients, referring to the knowledge gained in other rheumatic diseases.

Short-term outcomes of phosphodiesterase type 5 inhibitors for fetal growth restriction: a study protocol for a systematic review with individual participant data meta-analysis, aggregate meta-analysis, and trial sequential analysis

BACKGROUND

Early onset fetal growth restriction secondary to placental insufficiency can lead to severe maternal and neonatal morbidity and mortality. Pre-clinical studies and a few small randomised clinical trials have suggested that phosphodiesterase type 5 (PDE-5) inhibitors may have protective effects against placental insufficiency in this context; however, robust evidence is lacking. The STRIDER Consortium conducted four randomised trials to investigate the use of a PDE-5 inhibitor, sildenafil, for the treatment of early onset fetal growth restriction. We present a protocol for the pre-planned systematic review with individual participant data meta-analysis, aggregate meta-analysis, and trial sequential analysis of these and other eligible trials. The main objective of this study will be to evaluate the effects of PDE-5 inhibitors on neonatal morbidity compared with placebo or no intervention among pregnancies with fetal growth restriction.

METHODS

We will search the following electronic databases with no language or date restrictions: OVID MEDLINE, OVID EMBASE, the Cochrane Controlled Register of Trials (CENTRAL), and the clinical trial registers Clinicaltrials.gov and World Health Organisation International Clinical Trials Registry Platform (ICTRP). We will identify randomised trials of PDE-5 inhibitors in singleton pregnancies with growth restriction. Two reviewers will independently screen all citations, full-text articles, and abstract data. Our primary outcome will be infant survival without evidence of serious adverse neonatal outcome. Secondary outcomes will include gestational age at birth and birth weight z-scores. We will assess bias using the Cochrane Risk of Bias 2 tool. We will conduct aggregate meta-analysis using fixed and random effects models, Trial Sequential Analysis, and individual participant data meta-analysis using one- and two-stage approaches. The certainty of evidence will be assessed with GRADE.

DISCUSSION

This pre-defined protocol will minimise bias during analysis and interpretation of results, toward the goal of providing robust evidence regarding the use of PDE-5 inhibitors for the treatment of early onset fetal growth restriction.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (CRD42017069688).

Placental Ischemia Says "NO" to Proper NOS-Mediated Control of Vascular Tone and Blood Pressure in Preeclampsia

In this review, we first provide a brief overview of the nitric oxide synthase (NOS) isoforms and biochemistry. This is followed by describing what is known about NOS-mediated blood pressure control during normal pregnancy. Circulating nitric oxide (NO) bioavailability has been assessed by measuring its metabolites, nitrite (NO₂) and/or nitrate (NO₃), and shown to rise throughout normal pregnancy in humans and rats and decline postpartum. In contrast, placental malperfusion/ischemia leads to systemic reductions in NO bioavailability leading to maternal endothelial and vascular dysfunction with subsequent development of hypertension in PE. We end this article by describing emergent risk factors for placental malperfusion and ischemic disease and discussing strategies to target the NOS system therapeutically to increase NO bioavailability in preeclamptic patients. Throughout this discussion, we highlight the critical importance that experimental animal studies have played in our current understanding of NOS biology in normal pregnancy and their use in finding novel ways to preserve this signaling pathway to prevent the development, treat symptoms, or reduce the severity of PE.

Pharmacokinetics and pharmacodynamics of sildenafil in fetal lambs on extracorporeal support

BACKGROUND

Maternal transplacental administration of sildenafil is being considered for a variety of fetal conditions. Clinical translation also requires evaluation of fetal safety in a higher species, such as the fetal lamb. Experiments with the pregnant ewe are curtailed by minimal transplacental transfer as well as limited access to the fetus. The EXTra-uterine Environment for Neonatal Development (EXTEND) model renders the isolated fetal lamb readily accessible and allows for direct fetal administration of sildenafil.

METHODS

Five fetal lambs were placed on extracorporeal support in the EXTEND device and received continuous intravenous (IV) sildenafil (0.3-0.5-0.7 mg/kg/24hr) for a duration of one to seven days. Plasma sildenafil concentrations were sampled at regular intervals to establish the pharmacokinetic profile using population pharmacokinetic modeling. Serial Doppler ultrasound examination, continuous non-invasive hemodynamic monitoring and blood gas analysis were done to evaluate the pharmacodynamic effects and fetal response.

FINDINGS

The target concentration range (47-500 ng/mL) was attained with all doses. Sildenafil induced an immediate and temporary reduction of pulmonary vascular resistance, mean arterial pressure and circuit flow, without change in fetal lactate levels and acid-base status. The duration of the systemic effects increased with the dose.

INTERPRETATION

Immediate temporary pulmonary vascular and systemic hemodynamic changes induced by sildenafil were biochemically well tolerated by fetal lambs on extracorporeal support, with the 0.5 mg/kg/24 h dose balancing rapid attainment of target concentrations with short-lived systemic effects.

RESEARCH IN CONTEXT

None.

SEARCH STRATEGY BEFORE UNDERTAKING THE STUDY

A literature review was conducted searching online databases (Medline, Embase and Cochrane), using search terms: fetal OR prenatal OR antenatal AND sildenafil, without time-limit and excluding human studies. Where relevant, investigators were contacted in order to avoid duplication of work.

EVIDENCE BEFORE THIS STUDY

Prenatal therapy with sildenafil, a phosphodiesterase-5 inhibitor with vasodilatory and anti-remodeling effects on vascular smooth muscle cells, has been considered for a variety of fetal conditions. One multicenter clinical trial investigating the benefit of sildenafil in severe intrauterine growth restriction (the STRIDER-trial) was halted early due to excess mortality in the sildenafil-exposed arm at one treatment site. Such findings demonstrate the importance of extensive preclinical safety assessment in relevant animal models. Transplacentally administered sildenafil leads to decreased pulmonary arterial muscularization, preventing or reducing the occurrence of pulmonary hypertension in rat and rabbit fetuses with diaphragmatic hernia (DH). Validation of these results in a higher and relevant animal model, e.g. fetal lambs, is the next step to advance clinical translation. We recently demonstrated that, in contrast to humans, transplacental transfer of sildenafil in sheep is minimal, precluding the in vivo study of fetal effects at target concentrations using the conventional pregnant ewe model.

ADDED VALUE OF THIS STUDY

We therefore used the extracorporeal support model for fetal lambs, referred to as the EXTra-uterine Environment for Neonatal Development (EXTEND) system, bypassing placental and maternal metabolism, to investigate at what dose the target concentrations are reached, and what the fetal hemodynamic impact and response are. Fetal hemodynamic and metabolic tolerance to sildenafil are a crucial missing element on the road to clinical translation. This is therefore the first study investigating the pharmacokinetics, hemodynamic and biochemical effects of clinical-range concentrations of sildenafil in fetal lambs, free from placental and maternal interference.

IMPLICATIONS OF ALL THE AVAILABLE EVIDENCE

We demonstrated self-limiting pulmonary vasodilation, a decrease of both systemic arterial pressures and circuit flows, induced by clinical range concentrations of sildenafil, without the development of fetal acidosis. This paves the way for further investigation of prenatal sildenafil in fetal lambs on extracorporeal support. A dose of 0.5 mg/kg/24 h offered the best trade-off between rapid achievement of target concentrations and shortest duration of systemic effects. This is also the first study using the EXTEND as a model for pharmacotherapy during pregnancy.

Use of sildenafil and other phosphodiesterase type 5 inhibitors among pregnant women in Scandinavia

INTRODUCTION

For phosphodiesterase type 5 (PDE5) inhibitors, such as sildenafil, the only approved indication in women is for pulmonary arterial hypertension. These drugs are increasingly being proposed and tested for treatment of female infertility and complications in pregnancy. However, the extent of use of PDE5 inhibitors in the general pregnant population over the last decades is unknown. Therefore, we conducted a descriptive cohort study using data from the population health registers in the Scandinavian countries.

MATERIAL AND METHODS

By linking the Medical Birth Registers and the Prescribed Drug Registers in Denmark (1997-2017), Norway (2004-2017), and Sweden (2006-2016), women with filled prescriptions of PDE5 inhibitors in outpatient settings in the 90 days before the date of last menstrual period and/or during pregnancies were identified. With additional linkage to the National Patient Registers, information on maternal, pregnancy, and infant characteristics, co-morbidities, and co-medication was collected and described.

RESULTS

Among over 3 million singleton pregnancies, only 77 were pregnancies in women who had at least one filled prescription of a PDE5 inhibitor within the 90 days before the start of pregnancy to delivery. Prescription fills most often occurred before the last menstrual period and in the first trimester, with very few occurring later in pregnancy. Sildenafil was the most used PDE5 inhibitor. Among pregnant women using PDE5 inhibitors, 44% were 35 years of age or older, eight had a cardiovascular diagnosis, and three specifically had a diagnosis of pulmonary arterial hypertension. Among the infants born to mothers using PDE5 inhibitors, nine were born preterm, six were small-for-gestational age, five had an Apgar score at 5 minutes below 8, 18 were admitted to the Neonatal Intensive Care Unit, and eight had respiratory and cardiovascular conditions.

CONCLUSIONS

Few women used PDE5 inhibitors in outpatient settings before or during pregnancy in the Scandinavian countries in the last decades. Only a small proportion had a diagnosis for pulmonary arterial hypertension, suggesting off-label use in the remaining users. Use was predominantly in mothers over age 35 years. The safety of fetal exposure to sildenafil and other PDE5 inhibitors in pregnancy has not been established. As maternal age continues to increase and additional uses of PDE5 inhibitors are investigated, the safety of these drugs in pregnancy should be thoroughly evaluated.

Current State of Preeclampsia Mouse Models: Approaches, Relevance, and Standardization

Preeclampsia (PE) is a multisystemic, pregnancy-specific disorder and a leading cause of maternal and fetal death. PE is also associated with an increased risk for chronic morbidities later in life for mother and offspring. Abnormal placentation or placental function has been well-established as central to the genesis of PE; yet much remains to be determined about the factors involved in the development of this condition. Despite decades of investigation and many clinical trials, the only definitive treatment is parturition. To better understand the condition and identify potential targets preclinically, many approaches to simulate PE in mice have been developed and include mixed mouse strain crosses, genetic overexpression and knockout, exogenous agent administration, surgical manipulation, systemic adenoviral infection, and trophoblast-specific gene transfer. These models have been useful to investigate how biological perturbations identified in human PE are involved in the generation of PE-like symptoms and have improved the understanding of the molecular mechanisms underpinning the human condition. However, these approaches were characterized by a wide variety of physiological endpoints, which can make it difficult to compare effects across models and many of these approaches have aspects that lack physiological relevance to this human disorder and may interfere with therapeutic development. This report provides a comprehensive review of mouse models that exhibit PE-like symptoms and a proposed standardization of physiological characteristics for analysis in murine models of PE.

Transplacental Transfer and Fetal Pharmacodynamics of Sildenafil in the Pregnant Sheep Model

BACKGROUND

Sildenafil is a phosphodiesterase-5 inhibitor considered for antenatal use for a variety of indications. We sought to assess sildenafil pharmacokinetics in the pregnant ewe and fetus and evaluate its physiological fetal effects.

METHODS

Twelve fetal lambs (127-133 days GA, term 145) were chronically catheterized in utero. Ewes received different doses of sildenafil, either via subcutaneous injection (1.6, 2.0 mg/kg/day) or intravenous (IV) infusion (3, 5, 7, 10, and 12 mg/kg/day). Maternal and fetal sildenafil concentrations and metabolic status (blood gas analysis) were measured at given intervals. The fetal heart rate, pulmonary blood flow, systemic and aortic pressure, and maternal uterine artery pressure were continuously monitored.

RESULTS

The transplacental sildenafil transfer was 2.9% (range: 1.4-7.8%), preventing attainment of fetal target concentrations without toxic maternal levels. IV sildenafil infusion induced an immediate, temporary, dose-dependent reduction of pulmonary vascular resistance (38-78%) and increased both pulmonary blood flow (32-132%) and heart rate (13-49%), with limited nonlinear dose-dependent effects on systemic and pulmonary pressures. Fetal and maternal blood gases and maternal uterine artery pressures were unaffected by sildenafil infusion.

CONCLUSION

In sheep, transplacental transfer of sildenafil is extremely low. Though, minimal fetal sildenafil concentrations induce an acute transient pulmonary vasodilation, well-tolerated by the fetus and ewe.

Emerging antenatal therapies for congenital diaphragmatic hernia-induced pulmonary hypertension in preclinical models

Congenital diaphragmatic hernia (CDH)-related deaths are the largest contributor to in-hospital neonatal deaths in children with congenital malformations. Morbidity and mortality in CDH are directly related to the development of pulmonary hypertension (PH). Current treatment consists of supportive measures. To date, no pharmacotherapy has been shown to effectively reverse the hallmark finding of pulmonary vascular remodeling that is associated with pulmonary hypertension in CDH (CDH-PH). As such, there is a great need for novel therapies to effectively manage CDH-PH. Our review aims to evaluate emerging therapies, and specifically focuses on those that are still under investigation and not approved for clinical use by the Food and Drug Administration. Therapies were categorized into antenatal pharmacotherapies or antenatal regenerative therapies and assessed on their method of administration, safety profile, the effect on pulmonary vascular pathophysiology, and overall efficacy. In general, emerging antenatal pharmaceutical and regenerative treatments primarily aim to alleviate pulmonary vascular remodeling by restoring normal function and levels of key regulatory factors involved in pulmonary vascular development and/or in promoting angiogenesis. Overall, while these emerging therapies show great promise for the management of CDH-PH, most require further assessment of safety and efficacy in preclinical models before translation into the clinical setting. IMPACT: Emerging antenatal therapies for congenital diaphragmatic hernia-induced pulmonary hypertension (CDH-PH) show promise to effectively mitigate vascular remodeling in preclinical models. Further investigation is needed in preclinical and human studies to evaluate safety and efficacy prior to translation into the clinical arena. This review offers a comprehensive and up-to-date summary of emerging therapies currently under investigation in experimental animal models. There is no cure for CDH-PH. This review explores emerging therapeutic options for the treatment of CDH-PH and evaluates their impact on key molecular pathways and clinical markers of disease to determine efficacy in the preclinical stage.

Preeclampsia beyond pregnancy: long-term consequences for mother and child

Preeclampsia is defined as new-onset hypertension after the 20th wk of gestation along with evidence of maternal organ failure. Rates of preeclampsia have steadily increased over the past 30 yr, affecting ∼4% of pregnancies in the United States and causing a high economic burden (22, 69). The pathogenesis is multifactorial, with acknowledged contributions by placental, vascular, renal, and immunological dysfunction. Treatment is limited, commonly using symptomatic management and/or early delivery of the fetus (6). Along with significant peripartum morbidity and mortality, current research continues to demonstrate that the consequences of preeclampsia extend far beyond preterm delivery. It has lasting effects for both mother and child, resulting in increased susceptibility to hypertension and chronic kidney disease (45, 54, 115, 116), yielding lifelong risk to both individuals. This review discusses recent guideline updates and recommendations along with current research on these long-term consequences of preeclampsia.

Maternal Sildenafil vs Placebo in Pregnant Women With Severe Early-Onset Fetal Growth Restriction: A Randomized Clinical Trial

Importance

Severe early onset fetal growth restriction caused by placental dysfunction leads to high rates of perinatal mortality and neonatal morbidity. The phosphodiesterase 5 inhibitor, sildenafil, inhibits cyclic guanosine monophosphate hydrolysis, thereby activating the effects of nitric oxide, and might improve uteroplacental function and subsequent perinatal outcomes.

Objective

To determine whether sildenafil reduces perinatal mortality or major morbidity.

Design, Setting, and Participants

This placebo-controlled randomized clinical trial was conducted at 10 tertiary referral centers and 1 general hospital in the Netherlands from January 20, 2015, to July 16, 2018. Participants included pregnant women between 20 and 30 weeks of gestation with severe fetal growth restriction, defined as fetal abdominal circumference below the third percentile or estimated fetal weight below the fifth percentile combined with Dopplers measurements outside reference ranges or a maternal hypertensive disorder. The trial was stopped early owing to safety concerns on July 19, 2018, whereas benefit on the primary outcome was unlikely. Data were analyzed from January 20, 2015, to January 18, 2019. The prespecified primary analysis was an intention-to-treat analysis including all randomized participants.

Interventions

Participants were randomized to sildenafil, 25 mg, 3 times a day vs placebo.

Main Outcomes and Measures

The primary outcome was a composite of perinatal mortality or major neonatal morbidity until hospital discharge.

Results

Out of 360 planned participants, a total of 216 pregnant women were included, with 108 women randomized to sildenafil (median gestational age at randomization, 24 weeks 5 days [interquartile range, 23 weeks 3 days to 25 weeks 5 days]; mean [SD] estimated fetal weight, 458 [160] g) and 108 women randomized to placebo (median gestational age, 25 weeks 0 days [interquartile range, 22 weeks 5 days to 26 weeks 3 days]; mean [SD] estimated fetal weight, 464 [186] g). In July 2018, the trial was halted owing to concerns that sildenafil may cause neonatal pulmonary hypertension, whereas benefit on the primary outcome was unlikely. The primary outcome, perinatal mortality or major neonatal morbidity, occurred in the offspring of 65 participants (60.2%) allocated to sildenafil vs 58 participants (54.2%) allocated to placebo (relative risk, 1.11; 95% CI, 0.88-1.40; P = .38). Pulmonary hypertension, a predefined outcome important for monitoring safety, occurred in 16 neonates (18.8%) in the sildenafil group vs 4 neonates (5.1%) in the placebo group (relative risk, 3.67; 95% CI, 1.28-10.51; P = .008).

Conclusions and Relevance

These findings suggest that antenatal maternal sildenafil administration for severe early onset fetal growth restriction did not reduce the risk of perinatal mortality or major neonatal morbidity. The results suggest that sildenafil may increase the risk of neonatal pulmonary hypertension.

Trial Registration

ClinicalTrials.gov Identifier: NCT02277132.

Animal Models of Preeclampsia: Causes, Consequences, and Interventions

Preeclampsia is a common pregnancy complication, affecting 2% to 8% of pregnancies worldwide, and is an important cause of both maternal and fetal morbidity and mortality. Importantly, although aspirin and calcium are able to prevent preeclampsia in some women, there is no cure apart from delivery of the placenta and fetus, often necessitating iatrogenic preterm birth. Preclinical models of preeclampsia are widely used to investigate the causes and consequences of preeclampsia and to evaluate safety and efficacy of potential preventative and therapeutic interventions. In this review, we provide a summary of the published preclinical models of preeclampsia that meet human diagnostic criteria, including the development of maternal hypertension, together with new-onset proteinuria, maternal organ dysfunction, and uteroplacental dysfunction. We then discuss evidence from preclinical models for multiple causal factors of preeclampsia, including those implicated in early-onset and late-onset preeclampsia. Next, we discuss the impact of exposure to a preeclampsia-like environment for later maternal and progeny health. The presence of long-term impairment, particularly cardiovascular outcomes, in mothers and progeny after an experimentally induced preeclampsia-like pregnancy, implies that later onset or reduced severity of preeclampsia will improve later maternal and progeny health. Finally, we summarize published intervention studies in preclinical models and identify gaps in knowledge that we consider should be targets for future research.

Human Placental Vascular Reactivity in Health and Disease: Implications for the Treatment of Pre-eclampsia

Adequate development of the placenta is essential for optimal pregnancy outcome. Pre-eclampsia (PE) is increasingly recognized to be a consequence of placental dysfunction and can cause serious maternal and fetal complications during pregnancy. Furthermore, PE increases the risk of neonatal problems and has been shown to be a risk factor for cardiovascular disease of the mother later in life. Currently, there is no adequate treatment for PE, mainly because its multifactorial pathophysiology remains incompletely understood. It originates in early pregnancy with abnormal placentation and involves a cascade of dysregulated systems in the placental vasculature. To investigate therapeutic strategies it is essential to understand the regulation of vascular reactivity and remodeling of blood vessels in the placenta. Techniques using human tissue such as the ex vivo placental perfusion model provide insight in the vasoactive profile of the placenta, and are essential to study the effects of drugs on the fetal vasculature. This approach highlights the different pathways that are involved in the vascular regulation of the human placenta, changes that occur during PE and the importance of focusing on restoring these dysfunctional systems when studying treatment strategies for PE.

Sildenafil for Antenatal Treatment of Congenital Diaphragmatic Hernia: From Bench to Bedside

BACKGROUND

Persistent pulmonary hypertension (PPH) is one of the main causes of mortality and morbidity in infants affected by congenital diaphragmatic hernia (CDH). Since the structural changes that lead to PPH take place already in utero, a treatment starting in the prenatal phase may prevent the occurrence of this complication.

OBJECTIVE

To summarize the development process of antenatal sildenafil for CDH.

METHODS

The pharmacokinetics and efficacy of sildenafil have been assessed in the rat and the rabbit model. The transfer of the drug through the human placenta has been measured with the ex-vivo placenta perfusion model. Results from this experiment are being incorporated in a pregnancy-physiologically based pharmacokinetic (p- PBPK) model. A phase I-IIb placental transfer and safety study is ongoing.

RESULTS

Sildenafil administration to pregnant rats and rabbits led to therapeutic foetal drug levels without maternal and foetal toxicity, although it was associated with impaired vascular development in foetuses with nonhypoplastic lungs. Peak concentrations and 24-hour exposure were higher in pregnant rabbits compared to nonpregnant ones. In rat and rabbit foetuses with CDH, sildenafil rescued the lung vascular anomalies and partially improved parenchymal development. Sildenafil crossed the human placenta at a high rate ex-vivo, independently from the initial maternal concentration.

CONCLUSION

There is preclinical evidence that maternally administered sildenafil prevents the vascular changes that lead to PPH in CDH newborns. The phase I/IIb clinical study together with the p-PBPK model will define the maternal dose needed for a therapeutic effect in the foetus. Foetal safety will be investigated both in the clinical study and in the sheep. The final step will be a multicentre, randomized, placebo-controlled trial.

Effect of sildenafil on maternal hemodynamics in pregnancies complicated by severe early-onset fetal growth restriction: planned subgroup analysis from a multicenter randomized placebo-controlled double-blind trial

OBJECTIVES

Fetal growth restriction (FGR) is associated with maternal cardiovascular changes. Sildenafil, a phosphodiesterase type-5 inhibitor, potentiates the actions of nitric oxide, and it has been suggested that it alters maternal hemodynamics, potentially improving placental perfusion. Recently, the Dutch STRIDER trial was stopped prematurely owing to excess neonatal mortality secondary to pulmonary hypertension. The main aim of this study was to investigate the effect of sildenafil on maternal hemodynamics in pregnancies with severe early-onset FGR.

METHODS

This was a cardiovascular substudy within a UK multicenter, placebo-controlled trial, in which 135 women with a singleton pregnancy and severe early-onset FGR (defined as a combination of estimated fetal weight or abdominal circumference below the 10^th centile and absent/reversed end-diastolic flow in the umbilical artery on Doppler velocimetry, diagnosed between 22 + 0 and 29 + 6 weeks' gestation) were assigned randomly to receive either 25 mg sildenafil three times daily or placebo until 32 + 0 weeks' gestation or delivery. Maternal blood pressure (BP), heart rate (HR), augmentation index, pulse wave velocity (PWV), cardiac output, stroke volume (SV) and total peripheral resistance were recorded before randomization, 1-2 h and 48-72 h post-randomization, and 24-48 h postnatally. For continuous data, analysis was performed using repeated measures ANOVA methods including terms for timepoint, treatment allocation and their interaction.

RESULTS

Included were 134 women assigned randomly to sildenafil (n = 69) or placebo (n = 65) who had maternal BP and HR recorded at baseline. At 1-2 h post-randomization, compared with baseline values, sildenafil increased maternal HR by 4 bpm more than did placebo (mean difference, 5.00 bpm (95% CI, 1.00-12.00 bpm) vs 1.25 bpm (95% CI, -5.38 to 7.88 bpm); P = 0.004) and reduced systolic BP by 1 mmHg more (mean difference, -4.13 mmHg (95% CI, -9.94 to 1.44 mmHg) vs -2.75 mmHg (95% CI, -7.50 to 5.25 mmHg); P = 0.048). Even after adjusting for maternal mean arterial pressure, sildenafil reduced aortic PWV by 0.60 m/s more than did placebo (mean difference, -0.90 m/s (95% CI, -1.31 to -0.51 m/s) vs -0.26 m/s (95% CI, -0.75 to 0.59 m/s); P = 0.001). Sildenafil was associated with a non-significantly greater decrease in SV index after 1-2 h post-randomization than was placebo (mean difference, -5.50 mL/m² (95% CI, -11.00 to -0.50 mL/m² ) vs 0.00 mL/m² (95% CI, -5.00 to 4.00 mL/m² ); P = 0.056).

CONCLUSIONS

Sildenafil in a dose of 25 mg three times daily increases HR, reduces BP and reduces arterial stiffness in pregnancies complicated by severe early-onset FGR. These changes are short term, modest and consistent with the anticipated vasodilatory effect. They have no short- or long-term clinical impact on the mother. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Effects of nifedipine and sildenafil on placental hemodynamics and gas exchange during fetal hypoxemia in a chronic sheep model

INTRODUCTION

We hypothesized that nifedipine and sildenafil would have no detrimental effects on placental hemodynamics and gas exchange under fetal hypoxemia.

METHODS

In 33 chronically instrumented fetal sheep, placental volume blood flow (Q_Plac) and umbilical artery (UA) vascular impedance were measured by Doppler ultrasonography. Fetal carotid artery blood pressure and blood gas values were monitored. After baseline data collection, maternal and fetal hypoxemia were induced. Following hypoxemia phase data collection, 12 fetuses received sildenafil and 9 fetuses nifedipine infusion, and 12 fetuses served as controls receiving saline infusion. Data were collected 30 and 120 min after infusion was started. Then maternal oxygenation was normalized and normoxemia phase data were collected, while infusion was continued.

RESULTS

Hypoxemia significantly decreased fetal pO₂ and blood pressure. In the sildenafil group at 30- and 120-min hypoxemia + infusion phases, fetal blood pressure and Q_Plac were significantly lower and pCO₂ higher than at baseline without returning to baseline level at normoxemia + infusion phase. In hypoxemia, nifedipine did not affect fetal blood pressure or placental hemodynamics. Both in the sildenafil and nifedipine groups, fetal pO₂ remained significantly lower at normoxemia + infusion phase than in the control group. Umbilical artery vascular impedance did not change during the experiment.

DISCUSSION

In fetal hypoxemia, sildenafil had detrimental effects on placental hemodynamics that disturbed placental gas exchange. Nifedipine did not alter placental hemodynamics in hypoxemia but disturbed placental gas exchange upon returning to normoxemia. Umbilical artery vascular impedance did not reflect alterations in placental hemodynamics.

Antenatal sildenafil citrate treatment increases offspring blood pressure in the placental-specific Igf2 knockout mouse model of FGR

Fetal growth restriction (FGR), where a fetus fails to reach its genetic growth potential, affects up to 8% of pregnancies and is a major risk factor for stillbirth and adulthood morbidity. There are currently no treatments for FGR, but candidate therapies include the phosphodiesterase-5 inhibitor sildenafil citrate (SC). Randomized clinical trials in women demonstrated no effect of SC on fetal growth in cases of severe early onset FGR; however, long-term health outcomes on the offspring are unknown. This study aimed to assess the effect of antenatal SC treatment on metabolic and cardiovascular health in offspring by assessing postnatal weight gain, glucose tolerance, systolic blood pressure, and resistance artery function in a mouse model of FGR, the placental-specific insulin-like growth factor 2 (PO) knockout mouse. SC was administered subcutaneously (10 mg/kg) daily from embryonic day (E)12.5. Antenatal SC treatment did not alter fetal weight or viability but increased postnatal weight gain in wild-type (WT) female offspring (P < 0.05) and reduced glucose sensitivity in both WT (P < 0.01) and P0 (P < 0.05) female offspring compared with controls. Antenatal SC treatment increased systolic blood pressure in both male (WT vs. WT-SC: 117 ± 2 vs. 140 ± 3 mmHg, P < 0.0001; P0 vs. P0-SC: 113 ± 3 vs. 140 ± 4 mmHg, P < 0.0001; means ± SE) and female (WT vs. WT-SC: 121 ± 2 vs. 140 ± 2 mmHg, P < 0.0001; P0 vs. P0-SC: 117 ± 2 vs. 144 ± 4 mmHg, P < 0.0001) offspring at 8 and 13 wk of age. Increased systolic blood pressure was not attributed to altered mesenteric artery function. In utero exposure to SC may result in metabolic dysfunction and elevated blood pressure in later life.

NEW & NOTEWORTHY Sildenafil citrate (SC) is currently used to treat fetal growth restriction (FGR). We demonstrate that SC is ineffective at treating FGR, and leads to a substantial increase systolic blood pressure and alterations in glucose homeostasis in offspring. We therefore urge caution and suggest that further studies are required to assess the safety and efficacy of SC in utero, in addition to the implications on long-term health.

Tadalafil treatment for preeclampsia (medication in preeclampsia; MIE): a multicenter phase II clinical trial

Purpose: To evaluate the effectiveness and safety of tadalafil treatment for hypertensive disorder of pregnancy (HDP).Materials and methods: In an open-label, randomized clinical trial, singleton pregnancies with HDP between 20 and 33 weeks of gestation were randomized to take 20 mg oral tadalafil every day (tadalafil treatment group) or no drug (conventional treatment group). The primary outcome was prolongation of pregnancy from randomization to delivery. However, this article primarily focuses on the safety assessments performed in the tadalafil treatment for HDP population, because the safety of using PDE5 inhibitors as therapeutic agents for fetal growth restriction (FGR) has been a problem worldwide.Results: From October 2016 to March 2018, 28 patients were randomized to each group and two cases were excluded (tadalafil treatment group: 12 cases; conventional treatment group: 14 cases). The significant adverse events related to tadalafil did not occur in the tadalafil treatment group. Among maternal adverse events, specifically with regard to headaches, there were significant differences between the two groups (0% in tadalafil group versus 43% in conventional treatment group; p = .02). There was no difference in the prolongation period of pregnancy that served as primary outcomes in both the groups (17.5 d in tadalafil group versus 16.5 d in conventional group, p = .96). The significant adverse events occurred at the same frequency as between the conventional treatment group and the tadalafil treatment group. And, maternal headache decreased significantly in the tadalafil treatment group.Conclusions: Tadalafil treatment is safe for pregnant women with HDP. Moreover, tadalafil did not prolong the gestational period in pregnant women with HDP.

ACOG Practice Bulletin No. 202: Gestational Hypertension and Preeclampsia

Hypertensive disorders of pregnancy constitute one of the leading causes of maternal and perinatal mortality worldwide. It has been estimated that preeclampsia complicates 2-8% of pregnancies globally (). In Latin America and the Caribbean, hypertensive disorders are responsible for almost 26% of maternal deaths, whereas in Africa and Asia they contribute to 9% of deaths. Although maternal mortality is much lower in high-income countries than in developing countries, 16% of maternal deaths can be attributed to hypertensive disorders (). In the United States, the rate of preeclampsia increased by 25% between 1987 and 2004 (). Moreover, in comparison with women giving birth in 1980, those giving birth in 2003 were at 6.7-fold increased risk of severe preeclampsia (). This complication is costly: one study reported that in 2012 in the United States, the estimated cost of preeclampsia within the first 12 months of delivery was $2.18 billion ($1.03 billion for women and $1.15 billion for infants), which was disproportionately borne by premature births (). This Practice Bulletin will provide guidelines for the diagnosis and management of gestational hypertension and preeclampsia.

The effects of sildenafil in maternal and fetal outcomes in pregnancy: A systematic review and meta-analysis

BACKGROUND

The number of studies associating the use of sildenafil in gestation is increasing. This drug inhibits phosphodiesterase type 5 (PDE5), an enzyme responsible for degradation of nitric oxide, and its efficacy is greater in the placental territory, as the maternal side of the placenta have more PDE5 than other sites. For this reason, promising results have been observed related to the prevention of preeclampsia and intrauterine growth restriction and to improvement of maternal-fetal morbidity in cases of placental insufficiency.

OBJECTIVE

To evaluate the benefits of using sildenafil in pregnancy.

SEARCHED STRATEGY

MEDLINE, ClinicalTrials.gov, Embase, LILACS and Cochrane databases were searched through September 2018. There was no restriction in language or year of publication. This study was registered in PROSPERO (CRD42017060288).

SELECTION CRITERIA

Randomized clinical trials which used sildenafil for treatment or prevention of obstetric diseases compared with placebo were selected.

DATA COLLECTION AND ANALYSIS

The results were obtained using the inverse variance method for continuous variables and Man-Whitney for categorical variables.

MAIN RESULTS

Among a population of 598 pregnant women from the seven clinical trials included, 139 had pre-eclampsia, 275 had intrauterine growth restriction, and 184 had oligohydramnios. A significant increase of 222.58 grams [27.75 to 417.41] was observed in the fetal weight at birth of patients taking sildenafil. The other outcomes did not show any statistical significance. This may be due to the small number of patients used in each study and the great heterogeneity between the groups.

CONCLUSIONS

Sildenafil could be associated with increasing fetal weight at birth in placental insufficiency despite the limitations of this meta-analysis, even though more studies in this field are needed to introduce this drug into obstetric clinical practice.

Low Birth Weight, Blood Pressure and Renal Susceptibility

PURPOSE OF THE REVIEW

The purpose of this review is to highlight the clinical significance of increased renal risk that has its origins in fetal life. This review will also discuss the critical need to identify therapeutic interventions for use in a pregnancy complicated by placental dysfunction and intrauterine growth restriction that can mitigate the developmental origins of kidney disease without inflicting additional harm on the developing fetus.

RECENT FINDINGS

A reduction in nephron number is a contributory factor in the pathogenesis of hypertension and kidney disease in low birth weight individuals. Reduced nephron number may heighten susceptibility to a secondary renal insult, and recent studies suggest that perinatal history including birth weight should be considered in the assessment of renal risk in kidney donors. This review highlights current findings related to placental dysfunction, intrauterine growth restriction, increased risk for renal injury and disease, and potential therapeutic interventions.

Safety Evaluation of Tadalafil Treatment for Fetuses with Early-Onset Growth Restriction (TADAFER): Results from the Phase II Trial

Tadalafil is a phosphodiesterase 5 (PDE5) inhibitor with a long half-life, high selectivity, and rapid onset of action. Because the safety of using PDE5 inhibitors as therapeutic agents for fetal growth restriction (FGR) has been a problem worldwide, this paper primarily focuses on the safety assessments performed in the Tadalafil Treatment for Fetuses with Early-Onset Growth Restriction (TADAFER) II population. Neonatal and maternal adverse events were analyzed, in addition to fetal, neonatal, and infant death cases, six months after stopping the trial. Eighty-nine pregnant women with FGR were studied between September 2016 and March 2018 (45 and 44 in the tadalafil and conventional treatment groups, respectively). Seven (16%) deaths (four fetal, one neonatal, and two infant) in the control group, whereas only one neonatal death occurred in the tadalafil group. Although headache, facial flushing, and nasal hemorrhage occurred more frequently in the tadalafil group, these symptoms were Grade 1 and transient. In conclusion, this trial showed that tadalafil decreased the fetal and infant deaths associated with FGR. This is thought to be primarily due to pregnancy prolongation. Further studies are warranted to evaluate the efficacy of tadalafil in treating early-onset FGR.

Placental effects and transfer of sildenafil in healthy and preeclamptic conditions

Background

The phosphodiesterase-5 inhibitor (PDE5) sildenafil has emerged as a promising treatment for preeclampsia (PE). However, a sildenafil trial was recently halted due to lack of effect and increased neonatal morbidity.

Methods

Ex vivo dual-sided perfusion of an isolated cotyledon and wire-myography on chorionic plate arteries were performed to study the effects of sildenafil and the non-selective PDE inhibitor vinpocetine on the response to the NO donor sodium nitroprusside (SNP) under healthy and PE conditions. Ex vivo perfusion was also used to study placental transfer of sildenafil in 6 healthy and 2 PE placentas. Furthermore, placental mRNA and protein levels of eNOS, iNOS, PDE5 and PDE1 were quantified.

Findings

Sildenafil and vinpocetine significantly enhanced SNP responses in chorionic plate arteries of healthy, but not PE placentas. Only sildenafil acutely decreased baseline tension in arteries of both healthy and PE placentas. At steady state, the foetal-to-maternal transfer ratio of sildenafil was 0·37 ± 0·03 in healthy placentas versus 0·66 and 0·47 in the 2 PE placentas. mRNA and protein levels of PDE5, eNOS and iNOS were comparable in both groups, while PDE1 levels were lower in PE.

Interpretation

The absence of sildenafil-induced NO potentiation in arteries of PE placentas, combined with the non-PDE-mediated effects of sildenafil and the lack of PDE5 upregulation in PE, argue against sildenafil as the preferred drug of use in PE. Moreover, increased placental transfer of sildenafil in PE might underlie the neonatal morbidity in the STRIDER trial.

Fund

This study was funded by an mRACE Erasmus MC grant.

STRIDER NZAus: a multicentre randomised controlled trial of sildenafil therapy in early-onset fetal growth restriction

OBJECTIVE

To assess the effect of maternal sildenafil therapy on fetal growth in pregnancies with early-onset fetal growth restriction.

DESIGN

A randomised placebo-controlled trial.

SETTING

Thirteen maternal-fetal medicine units across New Zealand and Australia.

POPULATION

Women with singleton pregnancies affected by fetal growth restriction at 22⁺⁰ to 29⁺⁶ weeks.

METHODS

Women were randomised to oral administration of 25 mg sildenafil citrate or visually matching placebo three times daily until 32⁺⁰ weeks, birth or fetal death (whichever occurred first).

MAIN OUTCOME MEASURES

The primary outcome was the proportion of pregnancies with an increase in fetal growth velocity. Secondary outcomes included live birth, survival to hospital discharge free of major neonatal morbidity and pre-eclampsia.

RESULTS

Sildenafil did not affect the proportion of pregnancies with an increase in fetal growth velocity; 32/61 (52.5%) sildenafil-treated, 39/57 (68.4%) placebo-treated [adjusted odds ratio (OR) 0.49, 95% CI 0.23-1.05] and had no effect on abdominal circumference Z-scores (P = 0.61). Sildenafil use was associated with a lower mean uterine artery pulsatility index after 48 hours of treatment (1.56 versus 1.81; P = 0.02). The live birth rate was 56/63 (88.9%) for sildenafil-treated and 47/59 (79.7%) for placebo-treated (adjusted OR 2.50, 95% CI 0.80-7.79); survival to hospital discharge free of major neonatal morbidity was 42/63 (66.7%) for sildenafil-treated and 33/59 (55.9%) for placebo-treated (adjusted OR 1.93, 95% CI 0.84-4.45); and new-onset pre-eclampsia was 9/51 (17.7%) for sildenafil-treated and 14/55 (25.5%) for placebo-treated (OR 0.67, 95% CI 0.26-1.75).

CONCLUSIONS

Maternal sildenafil use had no effect on fetal growth velocity. Prospectively planned meta-analyses will determine whether sildenafil exerts other effects on maternal and fetal/neonatal wellbeing.

TWEETABLE ABSTRACT

Maternal sildenafil use has no beneficial effect on growth in early-onset FGR, but also no evidence of harm.

Current and emerging pharmacotherapy for emergency management of preeclampsia

INTRODUCTION

Preeclampsia is a disease specific to pregnancy characterised by new onset hypertension with maternal organ dysfunction and/or fetal growth restriction. It remains a major cause of maternal and perinatal morbidity and mortality. For fifty years, antihypertensives have been the mainstay of treating preeclampsia, reducing maternal morbidity and mortality. With increased knowledge of the mechanisms underlying the disease has come opportunities for novel therapies that complement antihypertensives by protecting the maternal vasculature. Areas covered: In this review, the authors consider, in detail, the antihypertensives commonly used today in the emergency care of women with severe preeclampsia. They also review less common anti-hypertensive agents and discuss the role of magnesium sulphate in the management of preeclampsia and the prevention of eclampsia. Finally, they explore novel therapeutics for the acute management of preeclampsia. Expert opinion: The rapid control of maternal hypertension will, and must, remain the mainstay of emergency treatment for women with severe preeclampsia. The role of magnesium sulphate as a primary prevention for eclampsia is context dependant and should not displace a focus on correcting blood pressure safely. The exploration of novel adjuvant therapies will likely allow us to prolong pregnancy longer and improve perinatal outcomes safely for the mother.

Detailed statistical analysis plan for the Dutch STRIDER (Sildenafil TheRapy In Dismal prognosis Early-onset fetal growth Restriction) randomised clinical trial on sildenafil versus placebo for pregnant women with severe early onset fetal growth restriction

OBJECTIVE

The objective of the Dutch Sildenafil therapy in dismal prognosis early onset fetal growth restriction (STRIDER) randomised clinical trial is to assess the beneficial and harmful effects of sildenafil versus placebo on fetal and neonatal mortality in pregnant women with severe early-onset fetal growth restriction. The objective of this detailed statistical analysis plan is to minimize the risks of selective reporting and data-driven analysis.

SETTING

The setting is 10 tertiary care hospitals and one secondary care hospital in The Netherlands.

PARTICIPANTS

The participants will be 360 pregnant women with severe early-onset fetal growth restriction.

INTERVENTIONS

The intervention is sildenafil 25 mg or placebo orally three times a day.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome is a composite of death or major neonatal morbidity assessed at hospital discharge. The secondary outcomes are neurodevelopmental impairment; mean scores of the Bayley III cognitive and motor assessment; the proportion of patients experiencing either preeclampsia or haemolysis, elevated liver enzymes, and low platelets syndrome; pulsatility index of uterine arteries, umbilical artery, and middle cerebral artery; birthweight; and gestational age at either delivery or intra-uterine death.

RESULTS

A detailed statistical analysis is presented, including pre-defined exploratory outcomes and planned subgroup analyses. One interim analysis after 180 patients had completed the study was planned and a strategy to minimise the risks of type I errors due to repetitive testing is presented. During review of this manuscript the interim analysis was performed by the Data Safety Monitoring Board and early stopping of the trial was recommended. Final analyses will be conducted independently by two statistically qualified persons following the present plan.

CONCLUSION

This pre-specified statistical analysis plan was written and submitted without knowledge of the unblinded data and updated after stopping of the trial at interim analysis.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02277132 . Registered on 29 September 2014. Original protocol for the study: doi: https://doi.org/10.5281/zenodo.56148.

Prenatal diagnosis and management of congenital diaphragmatic hernia

Congenital diaphragmatic hernia is characterized by failed closure of the diaphragm, thereby allowing abdominal viscera to herniate into the thoracic cavity and subsequently interfering with normal lung development. At birth, pulmonary hypoplasia leads to respiratory insufficiency and persistent pulmonary hypertension (PHT), that is lethal in up to 32% of patients. In isolated cases, the outcome may be predicted prenatally by medical imaging and advanced genetic testing. In those fetuses with a predicted poor outcome, fetoscopic endoluminal tracheal occlusion may be offered. This procedure is currently being evaluated in a global randomized clinical trial (www.TOTALtrial.eu). We are currently investigating alternative strategies including transplacental sildenafil administration to reduce the occurrence of persistent PHT.

Use of sildenafil citrate in cases of intrauterine growth restriction (IUGR); a prospective trial

OBJECTIVE

Intrauterine growth restriction (IUGR) is one of the most serious complications of pregnancy. Up to date, there is no evidence of achieving antenatal treatment of IUGR with abnormal placentation. Although, Sildenafil citrate has shown promising results, there are no firm conclusion till now. The aim of our study is to evaluate the use of Sildenafil citrate in the treatment of IUGR cases associated with impaired placental circulation.

MATERIALS AND METHODS

This was a prospective non-randomized study conducted at Mansoura university hospitals starting from March 2016 till October 2017. The studied population included singleton pregnancy and suffering from IUGR associated with impaired placental circulation.

RESULTS

This study included 50 pregnant women. Cases were divided into two groups. The first group received sildenafil citrate and the second control group did not receive sildenafil citrate. After 4 weeks after the 1st dose of Sildenafil significant decrease in umbilical artery Doppler indices. There was a statistically significant difference in the mean birth weight at delivery and neonatal admission to the newborn nursery in sildenafil group.

CONCLUSION

sildenafil citrate treatment may present a new hope towards better perinatal outcomes for pregnancies complicated by IUGR and impaired placental circulation that may help to decrease neonatal admission to the newborn nursery.

Targeting the vascular dysfunction: Potential treatments for preeclampsia

Preeclampsia is a pregnancy-specific disorder, primarily characterized by new-onset hypertension in combination with a variety of other maternal or fetal signs. The pathophysiological mechanisms underlying the disease are still not entirely clear. Systemic maternal vascular dysfunction underlies the clinical features of preeclampsia. It is a result of oxidative stress and the actions of excessive anti-angiogenic factors, such as soluble fms-like tyrosine kinase, soluble endoglin, and activin A, released by a dysfunctional placenta. The vascular dysfunction then leads to impaired regulation and secretion of relaxation factors and an increase in sensitivity/production of constrictors. This results in a more constricted vasculature rather than the relaxed vasodilated state associated with normal pregnancy. Currently, the only effective "treatment" for preeclampsia is delivery of the placenta and therefore the baby. Often, this means a preterm delivery to save the life of the mother, with all the attendant risks and burdens associated with fetal prematurity. To lessen this burden, there is a pressing need for more effective treatments that target the maternal vascular dysfunction that underlies the hypertension. This review details the vascular effects of key drugs undergoing clinical assessment as potential treatments for women with preeclampsia.

Sildenafil crosses the placenta at therapeutic levels in a dually perfused human cotyledon model

BACKGROUND

Sildenafil already is administered during gestation in patients with pulmonary hypertension and is under evaluation as a treatment for several pregnancy complications, such as preeclampsia and intrauterine growth restriction. Animal studies have shown a potential therapeutic effect of the drug in fetuses with congenital diaphragmatic hernia, rescuing peripheral pulmonary vasculature, and airway phenotype. When considering this drug for evaluation in a clinical trial, data on effective human placental drug passage are required.

OBJECTIVE

We quantified transplacental passage of sildenafil in the ex vivo dually perfused cotyledon model.

STUDY DESIGN

Six placentas that were collected after term delivery from healthy volunteers were cannulated and perfused dually. Sildenafil citrate was added to the maternal circulation at 2 different concentrations: 500 ng/mL, which represented the maximum tolerated concentration (n=3), and 50 ng/mL, which represented the therapeutic concentration (n=3). Samples were collected from both the fetal and the maternal reservoir at 0, 6, 30, 60, 90, 120, 150, and 180 minutes; the concentrations of sildenafil and its metabolite desmethyl-sildenafil were determined with the use of high performance liquid chromatography. The fetal/maternal concentration ratio was calculated for each timepoint. Transfer clearance was calculated as the rate of maternal to fetal passage/maternal concentration.

RESULTS

Sildenafil crossed the placenta at both maximal and therapeutic concentrations. Maternal and fetal levels reached a plateau at 90-120 minutes. Transfer clearance was the highest during the first hour of perfusion: 3.15 mL/min (range, 2.14-3.19 mL/min) for the maximum tolerated concentration and 3.07mL/min (range, 2.75-3.42 mL/min) for the therapeutic concentration (not significant). The fetomaternal concentration ratio significantly increased over time, up to 0.91±0.16 for the maximal concentration and 0.95±0.22 for the therapeutic concentration at the end of the perfusion (not significant). Desmethyl-sildenafil was not detected in any sample.

CONCLUSION

Sildenafil crosses the term placenta at a relatively high rate ex vivo, which suggests that there is sufficient placental transfer to reach clinically active fetal drug levels at the currently used maternal doses.

Sildenafil for the treatment of preeclampsia, an update: should we still be enthusiastic?

Preeclampsia is a hypertensive disorder of pregnancy and the clinical manifestation of severe endothelial dysfunction associated with maternal and foetal morbidity and mortality. The primum movens of the disease is the defect of invasion of the uterine arteries by foetal syncytiotrophoblasts, which causes a maladaptive placental response to chronic hypoxia and the secretion of the soluble form of type 1 vascular growth endothelial factor receptor, also called soluble fms-like tyrosine kinase 1 (sFlt-1), the major player in the pathophysiology of the disease. Among its different effects, sFlt-1 induces abnormal sensitivity of the maternal vessels to the vasoconstrictor angiotensin II. This leads to the hypertensive phenotype, recently shown to be abrogated by the administration of sildenafil citrate, which can potentiate the vasodilatory mediator nitrite oxide. This review focuses on the mechanisms of maternal endothelial dysfunction in preeclampsia and discusses the therapeutic window of sildenafil use in the context of preeclampsia, based on the results from preclinical studies and clinical trials. Safety issues recently reported in neonates have considerably narrowed this window.

Antihypertensive drug therapy for mild to moderate hypertension during pregnancy

BACKGROUND

Antihypertensive drugs are often used in the belief that lowering blood pressure will prevent progression to more severe disease, and thereby improve pregnancy outcome. This Cochrane Review is an updated review, first published in 2001 and subsequently updated in 2007 and 2014.

OBJECTIVES

To assess the effects of antihypertensive drug treatments for women with mild to moderate hypertension during pregnancy.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (13 September 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

All randomised trials evaluating any antihypertensive drug treatment for mild to moderate hypertension during pregnancy, defined as systolic blood pressure 140 to 169 mmHg and/or diastolic blood pressure 90 to 109 mmHg. Comparisons were of one or more antihypertensive drug(s) with placebo, with no antihypertensive drug, or with another antihypertensive drug, and where treatment was planned to continue for at least seven days.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

For this update, we included 63 trials (data from 58 trials, 5909 women), with moderate to high risk of bias overall.We carried out GRADE assessments for the main 'antihypertensive drug versus placebo/no antihypertensive drug' comparison only. Evidence was graded from very low to moderate certainty, with downgrading mainly due to design limitations and imprecision.For many outcomes, trials contributing data evaluated different hypertensive drugs; while we did not downgrade for this indirectness, results should be interpreted with caution.Antihypertensive drug versus placebo/no antihypertensive drug (31 trials, 3485 women)Primary outcomes: moderate-certainty evidence suggests that use of antihypertensive drug(s) probably halves the risk of developing severe hypertension (risk ratio (RR) 0.49; 95% confidence interval (CI) 0.40 to 0.60; 20 trials, 2558 women), but may have little or no effect on the risk of proteinuria/pre-eclampsia (average risk ratio (aRR) 0.92; 95% CI 0.75 to 1.14; 23 trials, 2851 women; low-certainty evidence). Moderate-certainty evidence also shows that antihypertensive drug(s) probably have little or no effect in the risk of total reported fetal or neonatal death (including miscarriage) (aRR 0.72; 95% CI 0.50 to 1.04; 29 trials, 3365 women), small-for-gestational-age babies (aRR 0.96; 95% CI 0.78 to 1.18; 21 trials, 2686 babies) or preterm birth less than 37 weeks (aRR 0.96; 95% CI 0.83 to 1.12; 15 trials, 2141 women).

SECONDARY OUTCOMES

we are uncertain of the effect of antihypertensive drug(s) on the risk of maternal death, severe pre-eclampsia, or eclampsia, orimpaired long-term growth and development of the baby in infancy and childhood, because the certainty of this evidence is very low. There may be little or no effect on the risk of changed/stopped drugs due to maternal side-effects, or admission to neonatal or intensive care nursery (low-certainty evidence). There is probably little or no difference in the risk of elective delivery (moderate-certainty evidence).Antihypertensive drug versus another antihypertensive drug (29 trials, 2774 women)Primary outcomes: beta blockers and calcium channel blockers together in the meta-analysis appear to be more effective than methyldopa in avoiding an episode of severe hypertension (RR 0.70; 95% CI 0.56 to 0.88; 11 trials, 638 women). There was also an increase in this risk when other antihypertensive drugs were compared with calcium channel blockers (RR 1.86; 95% CI 1.09 to 3.15; 5 trials, 223 women), but no evidence of a difference when methyldopa and calcium channel blockers together were compared with beta blockers (RR1.18, 95% CI 0.95 to 1.48; 10 trials, 692 women). No evidence of a difference in the risk of proteinuria/pre-eclampsia was found when alternative drugs were compared with methyldopa (aRR 0.78; 95% CI 0.58 to 1.06; 11 trials, 997 women), with calcium channel blockers (aRR: 1.24, 95% CI 0.70 to 2.19; 5 trials, 375 women), or with beta blockers (aRR 1.21, 95% CI 0.88 to 1.67; 12 trials, 1107 women).For the babies, we found no evidence of a difference in the risk oftotal reported fetal or neonatal death (including miscarriage) when comparing other antihypertensive drugs with methyldopa (aRR 0.77, 95% CI 0.52 to 1.14; 22 trials, 1791 babies), with calcium channel blockers (aRR 0.90, 95% CI 0.52 to 1.57; nine trials, 700 babies), or with beta blockers (aRR: 1.23, 95% CI 0.81 to 1.88; 19 trials, 1652 babies); nor in the risk for small-for-gestational age in the comparison with methyldopa (aRR 0.79, 95% CI 0.52 to 1.20; seven trials, 597 babies), with calcium channel blockers (aRR 1.05, 95% CI 0.64 to 1.73; four trials, 200 babies), or with beta blockers (average RR 1.13, 95% CI 0.80 to 1.60; 7 trials, 680 babies). No evidence of an overall difference among groups in the risk of preterm birth (less than 37 weeks) was found in the comparison with methyldopa (aRR: 0.91; 95% CI 0.68 to 1.22; 11 trials, 835 women), with calcium channel blockers (aRR 0.85, 95% CI 0.59 to 1.23; six trials, 330 women), or with beta blockers (aRR 1.22, 95% CI 0.90 to 1.66; 9 trials, 806 women).

SECONDARY OUTCOMES

There were no cases of maternal death andeclampsia. There is no evidence of a difference in the risk of severe pre-eclampsia, changed/stopped drug due to maternal side-effects, elective delivery, admission to neonatal or intensive care nursery when other antihypertensive drugs are compared with methyldopa, calcium channel blockers or beta blockers. Impaired long-term growth and development in infancy and childhood was not reported for these comparisons.

AUTHORS' CONCLUSIONS

Antihypertensive drug therapy for mild to moderate hypertension during pregnancy reduces the risk of severe hypertension. The effect on other clinically important outcomes remains unclear. If antihypertensive drugs are used, beta blockers and calcium channel blockers appear to be more effective than the alternatives for preventing severe hypertension. High-quality large sample-sized randomised controlled trials are required in order to provide reliable estimates of the benefits and adverse effects of antihypertensive treatment for mild to moderate hypertension for both mother and baby, as well as costs to the health services, women and their families.

Antenatal sildenafil administration to prevent pulmonary hypertension in congenital diaphragmatic hernia (SToP-PH): study protocol for a phase I/IIb placenta transfer and safety study

Background

Congenital diaphragmatic hernia is an orphan disease with high neonatal mortality and significant morbidity. An important cause for this is pulmonary hypertension, for which no effective postnatal therapy is available to date. An innovative strategy aiming at treating or preventing pulmonary hypertension more effectively is urgently needed. Prenatal sildenafil administration to expectant mothers prevented fetal and neonatal vascular changes leading to pulmonary hypertension in several animal models, and is, therefore, a promising approach. Before transferring this antenatal medical approach to the clinic, more information is needed on transplacental transfer and safety of sildenafil in humans.

Methods

This is a randomized, investigator-blinded, double-armed, parallel-group, phase I/IIb study with as a primary objective to measure the in-vivo transplacental transfer of sildenafil in women in the second and early third trimester of pregnancy (sub-study 1; weeks: 20.0–32.6) and at term (sub-study 2; weeks: 36.6–40). Participants will be randomized to two different sildenafil doses: 25 or 75 mg. In sub-study 1, a single dose of the investigational product will be administered to women undergoing termination of pregnancy, and maternal and fetal blood samples will be collected for determination of sildenafil concentrations. In sub-study 2, sildenafil will be administered three times daily from 3 days before planned delivery until actual delivery, following which maternal and umbilical cord samples will be collected. Proxies of maternal and fetal tolerance as well as markers of fetal pulmonary vasodilation will also be measured.

Discussion

This is the first study evaluating in-vivo transplacental passage of sildenafil in humans.

Trial registration

EU Clinical Trials Register 2016–002619-17, validated on 12 August 2016.

Trial sponsor: UZ Leuven, Herestraat 49, 3000 Leuven.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2897-8) contains supplementary material, which is available to authorized users.

Phosphodiesterase Inhibition in the Treatment of Preeclampsia: What Is New?

PURPOSE OF REVIEW

The present study intends to review the possibility of using phosphodiesterase inhibitors as a treatment option for preeclampsia, addressing potential risks and benefits.

RECENT FINDINGS

Preeclampsia is the most common hypertensive disorder of pregnancy, often responsible for severe maternal and fetal complications, which can lead to early pregnancy termination and death. Despite the numerous studies, its pathophysiology is still unclear, although it seems to involve a multiplicity of complex factors related to angiogenesis, ineffective vasodilation, oxidative stress, inflammatory cytokines, and endothelial dysfunction. It has been hypothetically suggested that the use of phosphodiesterase inhibitors is capable of improving placental and fetal perfusion, contributing to gestational scenario, by decreasing the symptomatology and severity of this syndrome. In this literature review, it has been found that most of the studies were conducted in animal models, and there is still lack of evidence supporting its use in clinical practice. Research in human indicates conflicting findings; randomized controlled trials were scarce and did not demonstrate any benefit in morbidity or mortality. Data regarding to pathophysiological and interventional research are described and commented in this review. The use of phosphodiesterase inhibitors in the treatment of preeclampsia is controversial and should not be encouraged taking into account recent data.