Contemporary neonatal outcome following rupture of membranes prior to 25 weeks with prolonged oligohydramnios

Prolonged oligohydramnios and the adverse composite outcome of death or severe neurodevelopmental impairment at 3 years of age in infants born at 22-29 gestational weeks

OBJECTIVE

To investigate the association between prolonged oligohydramnios and a composite outcome of death or severe neurodevelopmental impairment (NDI) at 3 years of age.

METHODS

This single-center retrospective cohort study enrolled infants born at 22-29 weeks of gestational age without major congenital anomalies. The patients were classified into three groups depending on the existence and duration of oligohydramnios: no/non-prolonged oligohydramnios (no or 0-7 days of oligohydramnios), prolonged oligohydramnios (8-14 days), and very prolonged oligohydramnios (> 14 days). The primary outcome was a composite of death or severe NDI, which was defined as severe cerebral palsy, developmental delay, severe visual impairment, or deafness at age 3.

RESULTS

Out of the 843 patients, 784 (93 %), 30 (3.6 %), and 29 (3.4 %) were classified into the no/non-prolonged, prolonged, and very prolonged oligohydramnios groups, respectively. After excluding patients lost to follow-up, the adverse composite outcome at 3 years of age was observed in 194/662 (29 %), 7/26 (27 %), and 8/23 (35 %) in the corresponding groups. The composite outcome showed no significant trend with the duration of oligohydramnios (P = 0.70). In a logistic regression model controlling the known predictors of gestational age, birth weight, small-for-gestational-age, male sex, multiple pregnancy, hypertensive disorders of pregnancy, antenatal corticosteroids, and the number of family-social risk factors, the duration of oligohydramnios was not independently associated with the composite outcome; odds ratio 1.3 (95 % confidence interval, 0.78-2.0).

CONCLUSION

Prolonged oligohydramnios was not associated with the composite outcome of death or severe NDI at 3 years of age.

Outcome of prelabor rupture of membranes before or at the limit of viability: systematic review and meta-analysis

OBJECTIVE

Counseling of pregnancies complicated by pre- and periviable premature rupture of membranes to reach shared decision-making is challenging, and the current limited evidence hampers the robustness of the information provided. This study aimed to elucidate the rate of obstetrical and neonatal outcomes after expectant management for premature rupture of membranes occurring before or at the limit of viability.

DATA SOURCES

Medline, Embase, CINAHL, and Web of Science databases were searched electronically up to September 2023.

STUDY ELIGIBILITY CRITERIA

Our study included both prospective and retrospective studies of singleton pregnancies with premature rupture of membranes before and at the limit of viability (ie, occurring between 14 0/7 and 24 6/7 weeks of gestation).

METHODS

Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies. Moreover, our study used meta-analyses of proportions to combine data and reported pooled proportions. Given the clinical heterogeneity, a random-effects model was used to compute the pooled data analyses. This study was registered with the International Prospective Register of Systematic Reviews database (registration number: CRD42022368029).

RESULTS

The pooled proportion of termination of pregnancy was 32.3%. After the exclusion of cases of termination of pregnancy, the rate of spontaneous miscarriage or fetal demise was 20.1%, whereas the rate of live birth was 65.9%. The mean gestational age at delivery among the live-born cases was 27.3 weeks, and the mean latency between premature rupture of membranes and delivery was 39.4 days. The pooled proportion of cesarean deliveries was 47.9% of the live-born cases. Oligohydramnios occurred in 47.1% of cases. Chorioamnionitis occurred in 33.4% of cases, endometritis in 7.0%, placental abruption in 9.2%, and postpartum hemorrhage in 5.3%. Hysterectomy was necessary in 1.2% of cases. Maternal sepsis occurred in 1.5% of cases, whereas no maternal death was reported in the included studies. When focusing on neonatal outcomes, the mean birthweight was 1022.8 g in live-born cases. The neonatal intensive care unit admission rate was 86.3%, respiratory distress syndrome was diagnosed in 66.5% of cases, pulmonary hypoplasia or dysplasia was diagnosed in 24.0% of cases, and persistent pulmonary hypertension was diagnosed in 40.9% of cases. Of the surviving neonates, the other neonatal complications included necrotizing enterocolitis in 11.1%, retinopathy of prematurity in 27.1%, and intraventricular hemorrhage in 17.5%. Neonatal sepsis occurred in 30.2% of cases, and the overall neonatal mortality was 23.9%. The long-term follow-up at 2 to 4 years was normal in 74.1% of the available cases.

CONCLUSION

Premature rupture of membranes before or at the limit of viability was associated with a great burden of both obstetrical and neonatal complications, with an impaired long-term follow-up at 2 to 4 years in almost 30% of cases, representing a clinical challenge for both counseling and management. Our data are useful when initially approaching such patients to offer the most comprehensive possible scenario on short- and long-term outcomes of this condition and to help parents in shared decision-making. El resumen está disponible en Español al final del artículo.

Impact of preterm premature rupture of membranes and oligohydramnios on in-hospital outcomes of very-low-birthweight infants

OBJECTIVE

To analyze neonatal outcomes in very-low-birthweight (VLBW) infants depending on the presence of preterm premature rupture of membranes (PPROM), oligohydramnios, or both.

METHODS

The electronic medical records of VLBW infants admitted during the study period, January 2013 to September 2018, were reviewed. Neonatal outcomes (primary outcome: neonatal death; secondary outcome: neonatal morbidity) were compared depending on whether the infant was affected by PPROM or oligohydramnios. Logistic regression analysis was performed to assess the association of PPROM and oligohydramnios with neonatal outcomes.

RESULTS

Three hundred and nineteen VLBW infants were included: (1) 141 infants in the PPROM group vs. 178 infants in the non-PPROM group, and (2) 54 infants in the oligohydramnios group vs. 265 infants in the non-oligohydramnios group. The infants affected by PPROM were at significantly younger gestational ages at birth with lower 5-min Apgar scores than those not affected by PPROM. Histologic chorioamnionitis was significantly more frequent in the PPROM group than in the non-PPROM group. The proportions of small-for-gestational-age infants and infants affected by multiple births were significantly higher in the non-PPROM group. The median (interquartile range) PPROM latency and onset were 50.5 (9.0 - 103.0) h and 26.6 (24.1 - 28.5) weeks, respectively. Based on the logistic regression analysis assessing the association of PPROM and oligohydramnios with the significant neonatal outcome, oligohydramnios was significantly associated with neonatal death (odds ratio [OR] = 2.831, 95% confidence interval [CI] 1.447 - 5.539), air leak syndrome (OR = 2.692, 95% CI 1.224 - 5.921), and persistent pulmonary hypertension (PPH) (OR = 2.380, 95% CI 1.244 - 4.555). PPROM per se was not associated with any neonatal outcome. However, early onset PPROM and prolonged PPROM latency were associated with neonatal morbidity and mortality. When PPROM was accompanied by oligohydramnios, it was associated with increased odds for PPH (OR = 2.840, 95% CI 1.335 - 6.044), retinopathy of prematurity (OR = 3.308, 95% CI 1.325 - 8.259), and neonatal death (OR = 2.282, 95% CI 1.021 - 5.103).

CONCLUSION

PPROM and oligohydramnios affect neonatal outcomes differently. Oligohydramnios, but not PPROM, is a significant risk factor for adverse neonatal outcomes, which is presumably related to pulmonary hypoplasia. Prenatal inflammation appears to complicate neonatal outcomes in infants affected by early PPROM and prolonged PPROM latency.

Effect of gestational age at laser therapy on perinatal outcome in monochorionic diamniotic pregnancies affected by twin-to-twin transfusion syndrome

OBJECTIVE

To evaluate the effect of gestational age at laser therapy for twin-to-twin transfusion syndrome (TTTS) on perinatal outcome.

DESIGN AND SETTINGS

Single retrospective observational cohort.

POPULATION

All consecutive pregnancies affected by TTTS and referred to our department between January 2013 and August 2020.

METHODS

Gestational age was modelled both as a categorical and as a continuous variable. Log-binomial regression was used to estimate the odds ratios (crude and adjusted for placental location, Quintero stage and cervical length) as well as the adjusted predicted probability of survival and fetal loss according to gestational age at laser therapy.

MAIN OUTCOMES

Fetal and neonatal survival, preterm prelabour rupture of membranes (PPROM).

RESULTS

Of the 503 pregnancies referred for TTTS, 431 were treated by laser therapy. Gestational age at laser therapy was positively and significantly associated with the overall survival at birth and at discharge (adjusted odds ratio [aOR] 1.12, 95% CI 1.05-1.19), as with a reduction in double fetal loss (aOR 0.81, 95% CI 0.71-0.92). Conversely, the rate of PPROM before 24 weeks was significantly higher in early cases (32% of PPROM <24 weeks when laser therapy was performed before 17 weeks versus 1.5% after 22 weeks, p < 0.001, aOR 0.60, 95% CI 0.48-0.72). Among the survivors, preterm birth before 28 weeks was significantly related to the gestational age at laser (OR 0.91, 95% CI 0.84-0.99), resulting in a significant impact on neonatal morbidity (OR 0.91, 95% CI 0.85-0.97).

CONCLUSION

Our results suggest a significant and independent impact of the gestational age at laser surgery on perinatal survival, PPROM and neonatal morbidity.

Physiological-based cord clamping versus immediate cord clamping for infants born with a congenital diaphragmatic hernia (PinC): study protocol for a multicentre, randomised controlled trial

INTRODUCTION

Pulmonary hypertension is a major determinant of postnatal survival in infants with a congenital diaphragmatic hernia (CDH). The current care during the perinatal stabilisation period in these infants might contribute to the development of pulmonary hypertension after birth-in particular umbilical cord clamping before lung aeration. An ovine model of diaphragmatic hernia demonstrated that cord clamping after lung aeration, called physiological-based cord clamping (PBCC), avoided the initial high pressures in the lung vasculature while maintaining adequate blood flow, thereby avoiding vascular remodelling and aggravation of pulmonary hypertension. We aim to investigate if the implementation of PBCC in the perinatal stabilisation period of infants born with a CDH could reduce the incidence of pulmonary hypertension in the first 24 hours after birth.

METHODS AND ANALYSIS

We will perform a multicentre, randomised controlled trial in infants with an isolated left-sided CDH, born at ≥35.0 weeks. Before birth, infants will be randomised to either PBCC or immediate cord clamping, stratified by treatment centre and severity of pulmonary hypoplasia on antenatal ultrasound. PBCC will be performed using a purpose-built resuscitation trolley. Cord clamping will be performed when the infant is considered respiratory stable, defined as a heart rate >100 bpm, preductal oxygen saturation >85%, while using a fraction of inspired oxygen of <0.5. The primary outcome is pulmonary hypertension diagnosed in the first 24 hours after birth, based on clinical and echocardiographic parameters. Secondary outcomes include neonatal as well as maternal outcomes.

ETHICS AND DISSEMINATION

Central ethical approval was obtained from the Medical Ethical Committee of the Erasmus MC, Rotterdam, The Netherlands (METC 2019-0414). Local ethical approval will be obtained by submitting the protocol to the regulatory bodies and local institutional review boards.

TRIAL REGISTRATION NUMBER

NCT04373902.

Predicting previable preterm premature rupture of membranes (pPPROM) before 24 weeks: maternal and fetal/neonatal risk factors for survival

We sought to compare maternal and neonatal risk factors in cases with previable premature rupture of membranes (pPPROM, between 14-24 weeks) for optimal counselling. Therefore, 192 pregnancies of 485 cases which met selection criteria and agreed to follow-up were retrospectively analysed. Mean gestational age at pPPROM was 20.45 weeks. Live births occurred in 171 cases, but 67 (39.2%) of them died in the neonatal period (neonatal death group) and 104 cases (60.8%) constituted surviving neonate group. Of the surviving neonates, 37 (33.7%) experienced at least one complication. Most seen maternal complications were chorioamnionitis (24.48%) and placental abruption (8.33%). Although amniotic fluid volume, length of pPPROM period, completing antibiotherapy and CRP values were significant, amniotic fluid volume and length of pPPROM showed also significance for multivariate regression analysis for maternal risk factors. Risk factors for birth were gestational age at pPPROM, gestational age at birth, new-born weight at birth, 1^st and 5^th minute Apgar scores, umbilical cord pH value and need for neonatal resuscitation. Furthermore, development of respiratory distress syndrome, necrotising enterocolitis, intraventricular haemorrhage and retinopathy of premature were additional risk factors for neonate. Of them, gestational age at birth, new-born weight at birth, respiratory distress syndrome and retinopathy of prematurity were also significant in multivariate regression analysis.Impact StatementWhat is already known on this subject? Management of previable premature rupture of membranes is controversial and there is no definite consensus on the approach. The factor that best predicts neonatal survival is the gestational age at birth (Deutsch et al. 2010).What do the results of this study add? Appropriate counselling for pPPROM cases is important especially during antenatal period (maternal factors) and postpartum period (neonatal factors). Maternal infection risk is increased with an increased latency period of PPROM. As the gestational age at birth increases, the survival rate increases and neonatal complication rates decrease. Other important determinants of neonatal survival and well-being are the presence of oligo-anhydramnios and latency period of previable PPROM to delivery.What are the implications of these findings for clinical practice and/or further research? Counselling the patient with previable PPROM about pregnancy complications and paediatric outcome is challenging because of the small size, different gestational age ranges, and retrospective nature of the multiple studies on this subject. The most important feature of our study was the relatively high number of patients compared to other series. Thus, we can counsel pregnant women with PPROM prior to 24 weeks of gestation about the maternal antenatal factors and neonatal postnatal factors with related outcomes and help make an informed decision regarding termination or conservative follow-up. Nevertheless, there is a need for larger multicentric prospective studies to validate our data and to establish the prognosis of previable PPROM for both mother and foetus.

Neonatal Outcomes according to the Latent Period from Membrane Rupture to Delivery among Extremely Preterm Infants Exposed to Preterm Premature Rupture of Membrane: a Nationwide Cohort Study

BACKGROUND

In accordance with the guidelines for the expectant management of women exposed to previable preterm premature rupture of membrane, we compared neonatal outcomes according to the latent period from membrane rupture to delivery among extremely preterm infants exposed to maternal preterm premature rupture of membrane using the Korean Neonatal Network database.

METHODS

Of the 3,305 extremely preterm infants born at 23-27 weeks' gestation between 2014 and 2017 who were registered in the Korean Neonatal Network, 1,464 infants were born to pregnant women who were exposed to preterm premature rupture of membrane. The short latency group was defined as infants born with a latent period between membrane rupture and delivery < 7 days (n = 450), whereas the prolonged latency group was defined as infants born with a latent period of ≥ 7 days (n = 434). Using well-established risk factors for adverse short-term outcomes, multivariate logistic regression analysis was performed to assess a prolonged latent period in preterm premature rupture of membrane as an independent risk factor for neonatal outcomes in extremely preterm infants exposed to preterm premature rupture of membrane.

RESULTS

The mean gestational age at membrane rupture in the prolonged latency group was significantly lower than that in the short latency group (22.7 ± 2.5 vs. 25.4 ± 1.3 weeks, P < 0.001). Nevertheless, the mean gestational age at delivery and birth weight were not significantly different between the two groups. The incidence of oligohydramnios and histologic chorioamnionitis in the prolonged latency group was significantly higher than that in the short latency group (38.7 [155/401] vs. 26.1 [105/403], 69.8 [270/384] vs. 61.0 [242/397], respectively, P < 0.05). The survival rate in the prolonged latency group did not differ from that in the short latency group (71.2 [309/434] vs. 73.3 [330/450], P = 0.478). Although the prolonged latency group was not associated with mortality during hospitalization in the multivariate logistic regression analysis, the prolonged latency group's early pulmonary hypertension and bronchopulmonary dysplasia rates were increased by 1.8 and 1.5 times, respectively.

CONCLUSION

A prolonged latent period of 7 days or more does not affect the survival rate but increases the risk of bronchopulmonary dysplasia occurrence among extremely preterm infants who are exposed to maternal preterm premature rupture of membrane.

The Controversy Persists: Is There a Qualification Criterion to Utilize Inhaled Nitric Oxide in Pre-term Newborns?

Inhaled nitric oxide (iNO) use in premature newborns remains controversial among clinicians. In 2014, the American Academy of Pediatrics, Committee on Fetus and Newborn released a statement that the available data do not support routine iNO use in pre-term newborns. Despite the absence of significant benefits, 2016 California data showed that clinicians continue to utilize iNO in pre-term infants. With studies as recent as January 2017, the Cochrane review confirmed no major advantages of iNO in pre-term newborns. Still, it recognized that a subset of pre-term infants with pulmonary hypertension (PHTN) had not been separately investigated. Furthermore, recent non-randomized controlled trials have suggested that iNO may benefit specific subgroups of pre-term newborns, especially those with PHTN, prolonged rupture of membranes, and antenatal steroid exposure. Those pre-term infants who showed a clinical response to iNO had increased survival without disability. These findings underscore the need for future studies in pre-term newborns with hypoxemic respiratory failure and PHTN. This review will discuss the rationale for using iNO, controversies regarding the diagnosis of PHTN, and additional novel approaches of iNO treatment in perinatal asphyxia and neonatal resuscitation in the pre-term population < 34 weeks gestation.

Neonatal outcome comparisons between preterm infants with or without early pulmonary hypertension following prolonged preterm premature rupture of membranes before 25 gestational weeks in Korean Neonatal Network

Objective: To determine the outcomes of very low birth weight infants (VLBWIs) following maternal mid-trimester prolonged preterm premature rupture of membranes (PPROM) and subsequent early pulmonary hypertension (PH).Design: Prospective cohort study.Setting: A nationwide web-based registry of VLBWIs from 67 neonatal intensive care units.Patients: VLBWIs registered on the Korean Neonatal Network and born between 23 and 34 gestational weeks.Methods: VLBWIs exposed to maternal PPROM prior to 25 gestational weeks and lasting ≥7 days (PPROM25, n = 402) were matched 1:1 with infants not exposed or exposed within 24 h to PPROM (CON, n = 402), using propensity score matching. The PPROM25 group was subdivided into PPROM25 groups with or without early PH, defined as exposure to inhaled nitric oxide or other pulmonary vasodilators to treat PH within 3 days of life. Clinical variables and major outcomes were compared, and risk factors for mortality and morbidities were analyzed.Results: Of 1790 infants with maternal PPROM, the PPROM25 group comprised 402 (22.5%) infants. Survival rates were similar between the CON and PPROM25 groups (71.6% vs 74.4%); however, the incidence of bronchopulmonary dysplasia (BPD) differed (47.8% and 60.2%, p < .05). Infants in the PPROM25 group with early PH had higher mortality (55.6%) and more severe intraventricular hemorrhage (IVH) (31.7%) than infants in the PPROM25 group without early PH (21.9% and 14.3%, respectively; p < .05). In multivariate analysis, lower 5 min Apgar score and the presence of oligohydramnios increased the risk of development of early PH. The presence of PPROM25 was founded to be a significant risk factor for BPD and early PH in relation to mortality and severe IVH, respectively.Conclusions: In VLBWIs, prolonged exposure to maternal mid-trimester PPROM increased the risk of BPD. Subsequent early PH immediately after birth increased mortality and severe IVH, thus, requires special attention.

Case report and literature review of management of preterm prelabour rupture of membranes before fetal viability

Preterm prelabour rupture of membranes (PPROM) complicates up to 3% of pregnancy and is responsible for one third of preterm deliveries. PPROM at extremely preterm gestations (<24 weeks) affects 0.4% of pregnancies and is associated with low neonatal survival rates, high rate of neonatal complications in survivors, and carries major risk of maternal morbidity and mortality. We present a rare case of pregnancy complicated by PPROM at 14 weeks which resulted in a term delivery and a good neonatal outcome.

Outcomes of hypoxic respiratory failure at birth associated with previable rupture of membranes

OBJECTIVE

To characterize clinical outcomes of infants born after previable rupture of membranes (pROM, < 23 weeks gestation and latency period ≥ 2 weeks) in relation to refractory hypoxic respiratory failure (rHRF).

STUDY DESIGN

pROM neonates categorized as rHRF (FiO₂ > 0.6 for ≥ 2 h) and treated (high frequency ventilation + inhaled nitric oxide) were compared with no rHRF group. Primary outcome was survival until discharge. Factors associated with rHRF and mortality were identified.

RESULT

Overall, mortality and disability rates were 28% and 22%, respectively. Treated rHRF group (n = 32) had longer period of ROM, mortality was (31% vs. 14%; p = 0.20), with similar survival-without-disability (54% vs. 47%; p = 0.67). Higher gestational age at birth [1.57 (1.03,2.39)] and cesarean delivery [12.6 (1.22,125)] were associated with increased survival.

CONCLUSION

Birth after pROM is associated with high rates of adverse outcomes, independent of latency period. Following treatment, rHRF infants may have similar long-term outcomes as those without rHRF.

Mid-trimester preterm premature rupture of membranes (PPROM): etiology, diagnosis, classification, international recommendations of treatment options and outcome

Mid-trimester preterm premature rupture of membranes (PPROM), defined as rupture of fetal membranes prior to 28 weeks of gestation, complicates approximately 0.4%-0.7% of all pregnancies. This condition is associated with a very high neonatal mortality rate as well as an increased risk of long- and short-term severe neonatal morbidity. The causes of the mid-trimester PPROM are multifactorial. Altered membrane morphology including marked swelling and disruption of the collagen network which is seen with PPROM can be triggered by bacterial products or/and pro-inflammatory cytokines. Activation of matrix metalloproteinases (MMP) have been implicated in the mechanism of PPROM. The propagation of bacteria is an important contributing factor not only in PPROM, but also in adverse neonatal and maternal outcomes after PPROM. Inflammatory mediators likely play a causative role in both disruption of fetal membrane integrity and activation of uterine contraction. The "classic PPROM" with oligo/an-hydramnion is associated with a short latency period and worse neonatal outcome compared to similar gestational aged neonates delivered without antecedent PPROM. The "high PPROM" syndrome is defined as a defect of the chorio-amniotic membranes, which is not located over the internal cervical os. It may be associated with either a normal or reduced amount of amniotic fluid. It may explain why sensitive biochemical tests such as the Amniosure (PAMG-1) or IGFBP-1/alpha fetoprotein test can have a positive result without other signs of overt ROM such as fluid leakage with Valsalva. The membrane defect following fetoscopy also fulfils the criteria for "high PPROM" syndrome. In some cases, the rupture of only one membrane - either the chorionic or amniotic membrane, resulting in "pre-PPROM" could precede "classic PPROM" or "high PPROM". The diagnosis of PPROM is classically established by identification of nitrazine positive, fern positive watery leakage from the cervical canal observed during in specula investigation. Other more recent diagnostic tests include the vaginal swab assay for placental alpha macroglobulin-1 test or AFP and IGFBP1. In some rare cases amniocentesis and infusion of indigo carmine has been used to confirm the diagnosis of PPROM. The management of the PPROM requires balancing the potential neonatal benefits from prolongation of the pregnancy with the risk of intra-amniotic infection and its consequences for the mother and infant. Close monitoring for signs of chorioamnionitis (e.g. body temperature, CTG, CRP, leucocytes, IL-6, procalcitonine, amniotic fluid examinations) is necessary to minimize the risk of neonatal and maternal complications. In addition to delayed delivery, broad spectrum antibiotics of penicillin or cephalosporin group and/or macrolide and corticosteroids have been show to improve neonatal outcome [reducing risk of chorioamnionitis (average risk ratio (RR)=0.66), neonatal infections (RR=0.67) and abnormal ultrasound scan of neonatal brain (RR=0.67)]. The positive effect of continuous amnioinfusion through the subcutaneously implanted perinatal port system with amniotic fluid like hypo-osmotic solution in "classic PPROM" less than 28/0 weeks' gestation shows promise but must be proved in future prospective randomized studies. Systemic antibiotics administration in "pre-PPROM" without infection and hospitalization are also of questionable benefit and needs to be further evaluated in well-designed randomized prospective studies to evaluate if it is associated with any neonatal benefit as well as the relationship to possible adverse effect of antibiotics on to fetal development and neurological outcome.

Association of Early Inhaled Nitric Oxide With the Survival of Preterm Neonates With Pulmonary Hypoplasia

IMPORTANCE

Pulmonary hypoplasia affects a very small percentage of preterm neonates, but its presence is associated with high rates of mortality.

OBJECTIVE

To determine whether treatment with inhaled nitric oxide during the first week of life was associated with improved in-hospital survival in a cohort of extremely preterm neonates with pulmonary hypoplasia.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the Pediatrix Medical Group's Clinical Data Warehouse, a data set containing information from more than 350 neonatal intensive care units in 35 US states and Puerto Rico. Since inhaled nitric oxide was not randomly prescribed, we used 1-to-1 propensity score matching to reduce the imbalance of measured covariates between the 2 treatment groups. The initial, unmatched cohort included singleton neonates who were born between 22 and 29 weeks' gestation, had a birth weight of 400 g or more, were diagnosed with pulmonary hypoplasia as a cause of their respiratory distress, remained free of major anomalies, and were discharged between January 1, 2000, and December 31, 2014. We defined exposure as the initiation of inhaled nitric oxide on day t in days 0 to 7 of the life of a neonate. Each exposed neonate was matched 1-to-1 to a neonate who had not initiated inhaled nitric oxide on a given day.

MAIN OUTCOMES AND MEASURES

The primary outcome was mortality defined as death prior to transfer or discharge home. Secondary outcomes were any-stage necrotizing enterocolitis, retinopathy of prematurity requiring treatment, chronic lung disease, and periventricular leukomalacia.

RESULTS

Among 92 635 neonates in our study sample, we identified 767 (0.8%) with pulmonary hypoplasia who met all study inclusion criteria, of whom 185 (0.2%) were exposed to inhaled nitric oxide. Among 151 matched pairs of exposed and unexposed neonates, we did not identify a significant association between inhaled nitric oxide use and mortality (hazard ratio [HR], 0.79; 95% CI, 0.57-1.11). Subgroup analyses of neonates with and without persistent pulmonary hypertension (PPHN) likewise revealed no significant association between inhaled nitric oxide use and mortality (pulmonary hypoplasia with PPHN: HR, 0.67; 95% CI, 0.45-1.01; pulmonary hypoplasia without PPHN: HR, 1.11; 95% CI, 0.61-2.02), but these findings may have been influenced by ascertainment bias.

CONCLUSIONS AND RELEVANCE

Early treatment with inhaled nitric oxide is not associated with improved survival among extremely preterm neonates with pulmonary hypoplasia. Clinical trials are warranted to clarify the matter.

[In the case of premature live birth, is very early rupture of the membranes an additional risk factor for morbidity and mortality?]

OBJECTIVE

To describe survival rate after preterm premature rupture of membranes (PPROM) before 25 weeks of gestation and compare neonatal morbidity and mortality among those born alive with a control group of infants born at a similar gestational age without premature rupture of membranes.

METHODS

We conducted a retrospective single-centre study at Port-Royal maternity, from 2007 to 2015, comparing neonatal outcomes between liveborninfants exposed to PPROM prior to 25 weeks of gestation (WG) and a control group not exposed to premature rupture of the membranes. For each live-born child, the next child born after spontaneous labor without PPROM was matched for gestational age at birth, sex, and whether or not they received antenatal corticosteroid therapy. The primary endpoint was severe neonatal complications assessed by a composite endpoint including neonatal deaths, grade 3-4 HIV, bronchopulmonary dysplasia, leukomalacia and stade 3-4 retinopathies.

RESULTS

Among 77 cases of very premature rupture of the membranes, 55 children were born alive. Among these, the average gestational age at birth was 28 WG and 1 day. The rate of severe neonatal complications did not differ between the two groups (43.6% in the PPROM group vs. 36.4%, P=0.44) and the survival rate at discharge was also similar in the two groups (85.5% vs. 83.6%, P=0.98).

CONCLUSIONS

In our cohort and among livebirths after 24 WG, PPROM before 25 WG was not associated with an increased risk of morbidity and mortality compared to children born at the same gestational age after a spontaneous labor with intact membranes.

Mid-childhood outcomes after pre-viable preterm premature rupture of membranes

OBJECTIVES

Investigate cardiorespiratory outcomes in children surviving previable preterm premature rupture of membranes (PV-PPROM) before 22 weeks' gestational age (GA) with minimum 2 weeks latency.

STUDY DESIGN

Single institution, follow-up of retrospectively identified children who were born after PV-PPROM during 2000-2004, and individually matched preterm-born controls.

RESULTS

Eleven PV-PPROM and matched control children were included at mean age of 10.5 and 10.7 years. Rupture of membranes occurred at mean GA 18² and 27⁶ weeks and birth at 28³ and 28⁶ weeks, respectively. Compared to controls, the PV-PPROM group had significantly poorer lung function, findings on echocardiography indicating mild pulmonary hypertension, and lower peak oxygen consumption. Chart reviews suggested more motor difficulties and a tendency towards more problems with learning and attention.

CONCLUSION

The findings highlight a preterm-born sub-group in need of targeted long-term monitoring and possibly interventions regarding future cardiorespiratory and neurodevelopmental function.

Pulmonary hypoplasia

To survive the transition to extrauterine life, newborn infants must have lungs that provide an adequate surface area and volume to allow for gas exchange. The dynamic activities of fetal breathing movements and accumulation of lung luminal fluid are key to fetal lung development throughout the various phases of lung development and growth, first by branching morphogenesis, and later by septation. Because effective gas exchange is essential to survival, pulmonary hypoplasia is among the leading findings on autopsies of children dying in the newborn period. Management of infants born prematurely who had disrupted lung development, especially at the pre-glandular or canalicular periods, may be challenging, but limited success has been reported. Growing understanding of stem cell biology and mechanical development of the lung, and how to apply them clinically, may lead to new approaches that will lead to better outcomes for these patients.

Preterm infant outcomes in relation to the gestational age of onset and duration of prelabour rupture of membranes: a retrospective cohort study

OBJECTIVE

To determine the hospital outcomes of liveborn infants at 23-31 weeks following prelabour preterm rupture of membranes (PPROM).

METHOD

A regional retrospective cohort study of 4454 infants of 23-31 weeks' gestation admitted to a tertiary neonatal network between 2007 and 2011. Primary outcome was the composite chronic lung disease (CLD) or mortality at discharge.

RESULTS

225 (5%) neonates had a history of PPROM occurring prior to 24⁺⁰ weeks (Early-PPROM), 829 (19%) had a history of PPROM at or after 24⁺⁰ weeks' gestation (Late-PPROM) and 3400 (76%) had no history of PPROM (No-PPROM). In comparison to No-PPROM, Early-PPROM group had higher CLD/mortality in infants born at 23-27 weeks (OR 1.95; 95% CI 1.34 to 2.85) and 28-31 weeks (OR 4.98; 95% CI 2.99 to 8.28). Within Early-PPROM group, the latency of PPROM >14 days had lower CLD/mortality in comparison to latency ≤14 days (57.6% vs 77%, OR 0.40; 95% CI 0.21 to 0.76). Late-PPROM group had significantly lower CLD/mortality in comparison to No-PPROM group at 23-27 weeks (OR 0.50; 95% CI 0.37 to 0.69) and 28-31 weeks (OR 0.50; 95% CI 0.36 to 0.71). Within Late-PPROM group, latency >14 days was associated with an increased CLD/mortality in 28-31 weeks (14.1% vs 5.4%, OR 2.88; 95% CI 1.31 to 6.38).

CONCLUSIONS

Early-PPROM prior to 24 weeks' gestation had high incidence of CLD/mortality even after correcting for gestational age. Late-PPROM at or after 24 weeks had lower CLD/mortality compared with No-PPROM. Latency >14 days in Late-PPROM group at 28-31 week group increased the odds of CLD/mortality.

Neonatal outcomes after prelabour rupture of membranes before 24 weeks' gestation

AIM

The aim of this study was to determine neonatal outcomes in pregnancies complicated by prelabour rupture of membranes (PROM) before 24 weeks' gestation.

METHODS

We performed a retrospective review of medical records over a 5-year period (2007-2011) at Mater Health Services, South Brisbane, Australia. Data relating to the antenatal and perinatal course of pregnancies complicated by PROM before 24 weeks' gestation were collected. Data were also collected on neonatal diagnoses, management and outcomes for all liveborn infants resulting from these pregnancies.

RESULTS

One hundred and six pregnancies were complicated by PROM before 24 weeks' gestation. Thirty-three (31%) of these pregnancies resulted in delivery at pre-viable gestations (<23 weeks). There were 36 (37%) infants who survived to hospital discharge. At discharge, 47% of infants had chronic lung disease, with 81% of this group requiring supplemental oxygen at home.

CONCLUSIONS

Almost one-third of pregnancies complicated by PROM before 24 weeks resulted in pre-viable preterm delivery. In pregnancies continuing to a viable gestation, there remained a significant risk of neonatal mortality and morbidity, primarily due to respiratory disease.

Inhaled nitric oxide in preterm infants with prolonged preterm rupture of the membranes: a case series

The available evidence does not support the routine use of inhaled nitric oxide (iNO) in the care of premature infants. We present a case series of 22 preterm infants born after prolonged preterm premature rupture of membranes and oligohydramnios with respiratory failure. Oxygenation index decreased significantly after commencement of iNO.

Neonatal survival after prolonged preterm premature rupture of membranes before 24 weeks of gestation

OBJECTIVE

To evaluate neonatal survival after prolonged preterm premature rupture of membranes (PROM) in the era of antenatal corticosteroids, surfactant, and inhaled nitric oxide.

METHODS

A single-center retrospective cohort study of neonates born from 2002-2011 after prolonged (1 week or more) preterm (less than 24 weeks of gestation) rupture of membranes was performed. The primary outcome was survival to discharge. Neonates whose membranes ruptured less than 24 hours before delivery (n=116) were matched (2:1) on gestational age at birth, sex, and antenatal corticosteroid exposure with neonates whose membranes ruptured 1 week or more before delivery (n=58). Analysis used conditional logistic regression for categorical data and Wilcoxon signed rank test for continuous data.

RESULTS

The prolonged preterm PROM exposed and unexposed cohorts had survival rates of 90% and 95%, respectively, although underpowered to assess the statistical significance (P=.313). Exposed neonates were more likely have pulmonary hypoplasia (26/58 exposed, 1/114 unexposed, P<.001), pulmonary hypertension (21/56 exposed, 10/112 unexposed, P<.001), and pulmonary air leak (21/58 exposed, 14/114 unexposed, P<.001). Gestational age at rupture (20.4 weeks exposed, 22.3 weeks unexposed, P=.189), length of rupture (3.7 weeks exposed, 6.4 weeks unexposed, P=.717), and lowest maximal vertical pocket before 24 weeks of gestation (0 cm exposed, 1.4 cm unexposed, P=.114) did not discriminate between survivors and nonsurvivors after exposure to prolonged preterm PROM.

CONCLUSION

With antenatal steroid exposure and aggressive pulmonary management, survival to discharge after prolonged preterm PROM was 90%. Pulmonary morbidities were common. Of note, the data were limited to women who remained pregnant 1 week or longer after rupture of membranes.

Severe midtrimester oligohydramnios: treatment strategies

PURPOSE OF REVIEW

Nearly 1% of pregnancies are affected by some type of midtrimester oligohydramnios. Evidence is currently accumulating that suggests the better efficacy of the new therapeutic procedures relative to conventional management. This review summarizes the available evidence.

RECENT FINDINGS

The prolongation of the period between the diagnosis of oligohydramnios and delivery following amnioinfusion and amniopatch techniques appears to be strongly associated with the gestational age and whether the situation was based on rupture of the membranes or not. Case series reveal that amnioinfusion significantly improves the perinatal outcome and prolongs the pregnancy in severe second-trimester oligohydramnios in both idiopathic cases and those involving rupture of the amniotic membranes [preterm prelabor rupture of the membranes (PPROM)]. There is clear evidence of a lower frequency of perinatal complications and successfully prolonged gestation in iatrogenic PPROM after the amniopatch technique relative to population controls.

SUMMARY

Identification of potentially modifiable risk factors for the successful prolongation of pregnancy complicated with midtrimester oligohydramnios, and previable PPROM is needed for the improvement of treatment strategies and prognosis. Randomized trials are needed to determine whether amniotic fluid-replenishing strategies can improve pregnancy outcomes.

Impact of duration of rupture of membranes on outcomes of premature infants

OBJECTIVE

The primary aim of the study was to determine how the risk of adverse outcomes was related to the duration of the latency period and gestational age at birth following preterm premature rupture of the fetal membranes (PPROM).

STUDY DESIGN

Retrospective review of infants discharged from 330 neonatal intensive care units. We defined four subgroups based on gestational age: 23 to 25, 26 to 28, 29 to 31 and 32 to 34 weeks. Each gestational age group was evaluated by duration of ROM: <24 h, 1 to 7 days, 8 to 14 days, 15 to 21 days, 21 to 28 days and >28 days and compared with a referent group (PPROM of >24 h but <7 days).

RESULT

In all, 239 808 non-anomalous infants 23 to 34 weeks' gestational age were identified; 37 233 (15.5%) had rupture of membranes (ROM) >24 h. Compared with a reference group (PPROM of >24 h but <7 days), the risk of mortality for PPROM of 8 to 14, 15 to 21 and 21 to 28 days varied depending on gestational age at birth. Only PPROM >28 days was consistently associated with increased mortality and decreased likelihood of survival without morbidity in all gestational age subgroups.

CONCLUSION

PPROM for >28 days is associated with an increased risk of death and morbidity.

Lung protective ventilation in extremely preterm infants

The lungs of an extremely preterm infant ≤28 weeks gestation are structurally and biochemically immature and vulnerable to injury from positive pressure ventilation. A lung protective approach to respiratory support is vital, aiming to ventilate an open lung, using the lowest pressure settings that maintain recruitment and oxygenation and avoiding hyperinflation with each tidal breath. For infants with severe respiratory distress syndrome and persistent atelectasis, lung protective ventilation requires recruitment using stepwise pressure increments, followed by reduction in ventilator pressures in search of an optimal point at which to maintain ventilation. Several studies, including a single randomised controlled trial, have found this lung protective strategy to be more effectively administered using high-frequency oscillatory ventilation rather than conventional ventilation. Many extremely preterm infants have minimal atelectasis and low oxygen requirements in the first days of life, and the ventilatory approach in this case should be one of avoidance of factors including overdistension that are known to contribute to later pulmonary deterioration. From a practical perspective, this means setting positive end-expiratory pressure at the lowest value that maintains oxygenation and restricting tidal volume using a volume-targeted mode of ventilation.

Transient defect in nitric oxide generation after rupture of fetal membranes and responsiveness to inhaled nitric oxide in very preterm infants with hypoxic respiratory failure

OBJECTIVE

To study antenatal risk factors and inflammatory responses during hypoxic respiratory failure (HRF) in infants of very low gestational age (VLGA, ≤32.0 weeks).

STUDY DESIGN

Of a cohort of 765 VLGA infants, 144 required mechanical ventilation. Airway specimens from these patients were prospectively studied. Infants who developed HRF (oxygenation index >25) with echocardiographic diagnosis of pulmonary hypertension were treated with inhaled nitric oxide (iNO). Three gestation comparison groups were formed on the basis of specific antenatal complications: prolonged preterm rupture of membranes (PPROM), spontaneous preterm birth, and preeclampsia. Chest radiographs were studied and airway specimens were analyzed for concentrations of tumor necrosis factor-α, interleukin (IL)-6, IL-8, IL-10, IL-12p70, IL-1β, and nitrite + nitrate over 4 days.

RESULTS

Seventeen (2.2% of all VLGA infants) developed HRF. In all 17 cases, PPROM complicated the antenatal course; these infants responded to iNO, regardless of infection or PPROM. The chest radiographs of HRF and non-HRF PPROM infants were similar. Airway proinflammatory cytokines and nitrite + nitrate levels were low in infants with HRF, but they increased during iNO treatment and remained elevated after discontinuation of iNO. Each of the 3 comparison groups had different and characteristic patterns of airway cytokines and nitrite + nitrate levels.

CONCLUSIONS

Seven percent of VLGA infants with preterm rupture of membranes and 15% of those with PPROM developed HRF, characterized by pulmonary hypertension that acutely responds to iNO. These infants may have a transient deficiency in the inflammatory response, including a defect in nitric oxide generation in airspaces.

Two-year neonatal outcome following PPROM prior to 25 weeks with a prolonged period of oligohydramnios

BACKGROUND

Improved neonatal survival data have been reported following early preterm prelabour rupture of membranes (PPROM) prior to 25 weeks gestation with a prolonged latency to delivery and persistent oligohydramnios. However, data regarding long-term respiratory and neurological morbidity are lacking.

AIMS

To evaluate the respiratory and neurological outcome data at two years of age in a cohort of infants born following PPROM prior to 25 weeks with a prolonged latency (14 days) to delivery and compare the data to an aged matched group of infants.

METHODS

Retrospective case note analysis over a 43-month period at Saint Luc University Hospital, Brussels.

RESULTS

15 surviving infants born following PPROM were matched to a group of 30 control infants. Although there was no significant difference in the incidence of BPD between the groups (33% vs 27%, p=0.24), the length of hospitalisation, duration of respiratory support and number of hospital readmissions for respiratory indications were all significantly higher for infants born following a prolonged period of oligohydramnios. There were no major anomalies on cranial ultrasound in the PPROM group and Baileys developmental assessment at 20-24 months corrected gestational age showed no difference between the two groups (Mental development index 93.9 vs 94.4 and Psychomotor development index 95.5 vs 95.8 respectively p = ns).

CONCLUSION

Neurodevelopmental outcome appears encouraging in this cohort although these infants are at high risk of prolonged initial hospitalisation and significant respiratory morbidity in the first two-years of life.

Pulmonary effects of prolonged oligohydramnios following mid-trimester rupture of the membranes--antenatal and postnatal management

Mid-trimester, preterm prelabour rupture of the membranes (PPROM) with prolonged oligohydramnios remains a challenge for both obstetricians and neonatologists. Although survival rates have improved, morbidity remains common particularly due to pulmonary insufficiency and pulmonary hypertension. The aetiology of abnormal lung development is unknown but may depend critically on pulmonary vascular development. Antenatal evaluation of at-risk foetuses by three-dimensional ultrasound and MRI is possible but the techniques need to be further assessed. Antenatal corticosteroids given in cases of PPROM reduce the incidence of neonatal death, respiratory distress syndrome, intraventricular haemorrhage and necrotising enterocolitis without increasing maternal or neonatal infection. The true risk-benefit ratio of antibiotics, tocolysis and strategies to normalise amniotic fluid volume remains less clear. There is no consensus regarding the optimal ventilation strategy to support infants with pulmonary insufficiency following PPROM, and further work is required to determine whether and which pulmonary vasodilators improve long-term outcome in these infants.

Combination therapy for life-threatening pulmonary hypertension in a premature infant: first report on bosentan use

Premature infants with preterm premature rupture of membranes (PPROM) are at high risk of severe respiratory failure because of lung hypodysplasia associated with persistent pulmonary hypertension of the newborn (PPHN). We describe the clinical course of a 28-week gestation infant with PPROM from the 20th week and prolonged oligohydramnios before delivery, who developed refractory hypoxia treated with oral bosentan as adjunct therapy to inhaled nitric oxide (iNO) and oral sildenafil. Conclusion Our experience suggests that bosentan can be used in the premature infant with PPHN after PPROM. To the best of our knowledge, this is the first report of bosentan treatment in a premature infant.

Early functional echocardiogram and inhaled nitric oxide: usefulness in managing neonates born following extreme preterm premature rupture of membranes (PPROM)

AIM

Poor neonatal outcome of preterm premature rupture of membranes (PPROM) < 24 weeks' gestational age (GA) is probably a result of abnormalities in both airway and vascular developments, ventilation perfusion mismatch, and possibly persistent pulmonary hypertension of the newborn (PPHN). Perinatal mortality of 50-90% has been reported in the past, with recent literature reporting significant improvement in neonatal survival. We report our 8-year experience in this group of infants using early diagnostic functional echocardiography (fECHO), high-frequency ventilation (HFV) and inhaled nitric oxide (iNO).

METHODS

The obstetric and neonatal databases were searched to identify babies with PPROM (< 20 weeks' gestation) or rupture earlier than 25 weeks for more than 14 days.

RESULTS

Twenty-six infants were identified, of whom 20 were admitted to the neonatal intensive care unit (NICU; mean GA 27.8 weeks, mean birth weight (BW) 1207 g). Early echocardiographic data were available in 12/15 infants requiring mechanical ventilation of whom 10 had evidence of PPHN. All infants who received iNO therapy survived to discharge and only two infants died. Survival to discharge was 69% for the whole cohort of infants and 90% for infants admitted to the NICU. In contrast, for the cohort from pre-iNO and -HFV era, the overall survival to discharge was 62% and 66% for the infants admitted to the NICU.

CONCLUSION

Premature infants with PPROM and presumed severe hypoxemic respiratory failure because of hypoplastic lungs often have significant PPHN and may show improvement in oxygenation after treatment with HFV and iNO. Early fECHO results in earlier identification and treatment of infants with PPHN in this high-risk group.

CPAP combined with inhaled nitric oxide for treatment of lung hypoplasia and persistent foetal circulation due to prolonged PPROM

BACKGROUND

Second trimester preterm premature rupture of the membranes (PPROM) before 24 weeks of gestation is associated with a high morbidity and mortality rate.

AIM

To demonstrate the efficacy of early continuous positive airway pressure (CPAP) combined with inhaled nitric oxide (iNO) for treatment of preterm infants with lung hypoplasia and persistent foetal circulation (PFC) due to very early PPROM and prolonged severe oligohydramnios.

METHODS

Seven infants with prolonged PPROM, lung hypoplasia, respiratory distress and persistent foetal circulation were intubated in the delivery room for subsequent surfactant and iNO application. As our new treatment strategy was to keep the period of mechanical ventilation as short as possible, all infants were switched on nasal CPAP combined with iNO within the first 24 hours.

RESULTS

Mean gestational age at PPROM was 19+6 weeks (range 14+2 to 23+6 weeks) and the average latency period between rupture of membranes and delivery was 10+3 weeks (7+3 to 16+4 weeks). Infants were born at 30+3 weeks of gestation (28+3 to 33+1 weeks) with an average birth weight of 1468g (884 to 2200g). In all neonates CPAP combined with iNO reversed PFC and 6 patients stabilised without the need for reintubation and mechanical ventilation. One infant had to be reintubated following 12 hours of CPAP combined with iNO due to respiratory insufficiency. All seven infants survived to discharge.

CONCLUSION

CPAP combined with iNO might be a promising approach for therapy of preterm infants with lung hypoplasia and persistent foetal circulation due to very early PPROM.