Consequences of meconium stained amniotic fluid: what does the evidence tell us?

The Placenta and Neonatal Encephalopathy with a Focus on Hypoxic-Ischemic Encephalopathy

Background: Placental examination is important for its diagnostic immediacy to correlate with maternal and/or fetal complications and parturitional difficulties. In a broader context, clinicopathologic studies of the placenta have addressed a range of pathogenetic questions that have led to conclusive and inconclusive results and interpretations. Methods: Recent standardized morphologic criteria and terminology of placental lesions have facilitated the ability to compare findings from studies that have focused on complications and outcomes of pregnancy. This review is an evaluation of recent studies on placental lesions associated with hypoxic-ischemic encephalopathy (HIE). Conclusion: No apparent consensus exists on whether it is fetal inflammation with the release of cytokines or chronic maternal and/or fetal vascular malperfusion is responsible for HIE with a lowering of the threshold for hypoxic ischemia. The counter argument is that HIE occurs solely as an intrapartum event. Additional investigation is necessary.

Meconium-stained amniotic fluid

Green-stained amniotic fluid, often referred to as meconium-stained amniotic fluid, is present in 5% to 20% of patients in labor and is considered an obstetric hazard. The condition has been attributed to the passage of fetal colonic content (meconium), intraamniotic bleeding with the presence of heme catabolic products, or both. The frequency of green-stained amniotic fluid increases as a function of gestational age, reaching approximately 27% in post-term gestation. Green-stained amniotic fluid during labor has been associated with fetal acidemia (umbilical artery pH <7.00), neonatal respiratory distress, and seizures as well as cerebral palsy. Hypoxia is widely considered a mechanism responsible for fetal defecation and meconium-stained amniotic fluid; however, most fetuses with meconium-stained amniotic fluid do not have fetal acidemia. Intraamniotic infection/inflammation has emerged as an important factor in meconium-stained amniotic fluid in term and preterm gestations, as patients with these conditions have a higher rate of clinical chorioamnionitis and neonatal sepsis. The precise mechanisms linking intraamniotic inflammation to green-stained amniotic fluid have not been determined, but the effects of oxidative stress in heme catabolism have been implicated. Two randomized clinical trials suggest that antibiotic administration decreases the rate of clinical chorioamnionitis in patients with meconium-stained amniotic fluid. A serious complication of meconium-stained amniotic fluid is meconium aspiration syndrome. This condition develops in 5% of cases presenting with meconium-stained amniotic fluid and is a severe complication typical of term newborns. Meconium aspiration syndrome is attributed to the mechanical and chemical effects of aspirated meconium coupled with local and systemic fetal inflammation. Routine naso/oropharyngeal suctioning and tracheal intubation in cases of meconium-stained amniotic fluid have not been shown to be beneficial and are no longer recommended in obstetrical practice. A systematic review of randomized controlled trials suggested that amnioinfusion may decrease the rate of meconium aspiration syndrome. Histologic examination of the fetal membranes for meconium has been invoked in medical legal litigation to time the occurrence of fetal injury. However, inferences have been largely based on the results of in vitro experiments, and extrapolation of such findings to the clinical setting warrants caution. Fetal defecation throughout gestation appears to be a physiologic phenomenon based on ultrasound as well as in observations in animals.

Impact of Thin Meconium on Delivery and Early Neonatal Outcomes

Several reports regarding the effects of thin meconium on maternal and neonatal outcomes are contradictory. This study evaluated the risk factors and obstetrical outcomes during deliveries complicated with thin meconium. This retrospective cohort study included all women with a singleton pregnancy, who underwent trial of labor >24 weeks of gestation, in a single tertiary center, over a six-year period. Obstetrical, delivery, and neonatal outcomes were compared between deliveries with thin meconium (thin meconium group) to deliveries with clear amniotic fluid (control group). Included in the study were 31,536 deliveries. Among them 1946 (6.2%) were in the thin meconium group and 29,590 (93.8%) were controls. Meconium aspiration syndrome was diagnosed in eight neonates in the thin meconium group and in none of the controls (0.41%, p < 0.001). In multivariate logistic regression analysis, the following adverse outcomes were found to be independently associated with increased odds ratio (OR) for thin meconium: intrapartum fever (OR 1.37, 95% CI 1.1-1.7), instrumental delivery (OR 1.26, 95% CI 1.09-1.46), cesarean delivery for non-reassuring fetal heart rate (OR 2.0, 95% CI 1.68-2.46), and respiratory distress requiring mechanical ventilation (OR 2.06, 95% CI 1.19-3.56). Thin meconium was associated with adverse obstetrical, delivery, and neonatal outcomes that should receive extra neonatal care and alert the pediatrician.

The Incidence and Outcomes of Late-Term Pregnancy

BACKGROUND

Little is known about the outcomes of late-term pregnancy. In this study, we aim to assess the incidence and adverse prenatal outcomes associated with late-term pregnancy.

METHODS

We retrospectively assessed all singleton pregnant mothers who gave birth at Khalij-e-Fars Hospital in Bandar Abbas, Iran, between January 2020 and 2022. All preterm and post-term deliveries were excluded. Mothers were divided into two groups: late-term mothers (41 0/7-41 6/7 weeks of gestation) and term mothers (37 0/7-40 6/7 weeks of gestation). Demographic factors, obstetric factors, maternal comorbidities, and prenatal outcomes were extracted from the electronic data of each mother. The incidence of late-term births was calculated. The chi-squared test was used to compare differences between the groups. Logistic regression models were used to assess the association of prenatal outcome with late-term pregnancy.

RESULTS

There were 8,888 singleton deliveries during the study period, and 1,269 preterm and post-term pregnancies were ruled out. Of the 7,619 deliveries, 309 (4.1%) were late-term, while 7,310 (95.9%) were term. There were no sociodemographic differences between term and late-term mothers. The late-term group had a higher prevalence of primiparous mothers, and the term group had a higher prevalence of diabetes. Late-term mothers had a higher risk of macrosomia (adjusted odds ratio (aOR): 2.24 (95% confidence interval (CI): 1.34-3.01)), meconium amniotic fluid (aOR: 2.32 (95% CI: 1.59-3.14)), and fetal distress (aOR: 2.38 (95% CI: 1.54-2.79)). When compared to term pregnancy, the risk of low birth weight (LBW) was lower in late-term pregnancy (aOR: 0.69 (95% CI: 0.36-0.81)).

CONCLUSIONS

Late-term pregnancy was found to be more likely to be associated with macrosomia, meconium amniotic fluid, and fetal distress, but serious maternal and neonatal adverse events were comparable to term pregnancy.

Clinical characteristics of meconium aspiration syndrome in neonates with different gestational ages and the risk factors for neurological injury and death: A 9-year cohort study

Background

The presence of meconium is associated with gestational age, and the incidence of meconium aspiration syndrome (MAS) increases with gestational age. Our study compared the differences in the clinical characteristics of patients with MAS at different gestational ages and discussed the risk factors for neurological injury and death from MAS.

Methods

A total of 294 neonates diagnosed with MAS between 2013 and 2021 were included. Patients were divided into preterm, early-term, full-term, and late-term groups according to gestational age. We compared the patients' basic demographic, treatment, complications, and clinical outcomes in the different groups. We also analyzed the risk factors of neurological injury and death in patients with MAS.

Results

The mean age at admission (0.55 ± 0.9 h) was lower and the proportion of cesarean deliveries (90.00%, 27/30) was higher in the preterm group than in the other three groups. There was no statistically significant difference among the four groups regarding 1- and 5-min Apgar scores and the need for delivery room resuscitation. In terms of complications, early-term infants had the highest incidence of neurological injury (52.9%, 27/51), and late-term infants had the highest incidence of pneumothorax (37.8%, 17/45). The overall mortality rate of children with MAS was 7.80% (23/294), and the difference in mortality rates among the four groups was not significant. Low 1-min Apgar score and gestational age, metabolic acidosis, and respiratory failure were independent risk factors for neurological injury; metabolic acidosis, respiratory failure, and sepsis were independent risk factors for death in neonates with MAS.

Conclusion

The clinical characteristics of MAS neonates of different gestational age are different mainly in complications. Early-term infants are more likely to complicate with neurological injury, and late-term infants are more likely to complicate with pneumothorax. Low 1-min Apgar score and gestational age, metabolic acidosis, and respiratory failure were established as risk factors for neurological injury; metabolic acidosis, respiratory failure, and sepsis were independent risk factors for death in neonates with MAS.

The incidence and risk factors of meconium amniotic fluid in singleton pregnancies: an experience of a tertiary hospital in Iran

BACKGROUND

Several common maternal or neonatal risk factors have been linked to meconium amniotic fluid (MAF) development; however, the results are contradictory, depending on the study. This study aimed to assess the prevalence and risk factors of MAF in singleton pregnancies.

METHODS

This study is a retrospective cohort that assessed singleton pregnant mothers who gave birth at a tertiary hospital in Bandar Abbas, Iran, between January 1st, 2020, and January 1st, 2022. Mothers were divided into two groups: 1) those diagnosed with meconium amniotic fluid (MAF) and 2) those diagnosed with clear amniotic fluid. Mothers with bloody amniotic fluid were excluded. Demographic factors, obstetrical factors, and maternal comorbidities were extracted from the electronic data of each mother. The Chi-square test was used to compare differences between the groups for categorical variables. Logistic regression models were used to assess meconium amniotic fluid risk factors.

RESULTS

Of 8888 singleton deliveries during the study period, 1085 (12.2%) were MAF. MAF was more common in adolescents, mothers with postterm pregnancy, and primiparous mothers, and it was less common in mothers with GDM and overt diabetes. The odds of having MAF in adolescents were three times higher than those in mothers 20-34 years old (aOR: 3.07, 95% CI: 1.87-4.98). Likewise, there were significantly increased odds of MAF in mothers with late-term pregnancy (aOR: 5.12, 95% CI: 2.76-8.94), and mothers with post-term pregnancy (aOR: 7.09, 95% CI: 3.92-9.80). Primiparous women were also more likely than multiparous mothers to have MAF (aOR: 3.41, 95% CI: 2.11-4.99).

CONCLUSIONS

Adolescents, primiparous mothers, and mothers with post-term pregnancies had a higher risk of MAF. Maternal comorbidities resulting in early termination of pregnancy can reduce the incidence of MAF.

Predictive value of new onset versus primary meconium-stained amniotic fluid

BACKGROUND

Transition of clear amniotic fluid to meconium-stained fluid is a relatively common occurrence during labor. However, data regarding the clinical significance and the prognostic value of the presence of meconium-stained amnionic fluid (MSAF) are scarce. This study aimed to investigate delivery and neonatal outcomes according to the presence of MSAF and the timing of the meconium passage.

METHODS

We used an historical cohort study at a single tertiary medical center in Israel between the years 2011 and 2018. Women were divided into two groups according to timing of meconium passage: primary MSAF (MSAF present at membrane rupture) and secondary MSAF (clear amnionic fluid that transitioned to MSAF during labor). Neonatal complication rates were compared between groups. Composite adverse neonatal outcome was defined as arterial cord blood pH &lt;7.1, 5 min Apgar score ≤7, and/or neonatal intensive care unit admission.

RESULTS

The study cohort included 56 863 singleton term births. Of these, 9043 (15.9%) were to women who had primary MSAF, and 1484 (2.6%) to those with secondary MSAF. Secondary MSAF compared with primary MSAF increased the risks of cesarean birth and operative vaginal delivery, increased the risks of low one- and five-minute Apgar scores and low arterial cord blood pH, and increased hospital stay duration. Multivariate analysis revealed that secondary MSAF was independently associated with an increased risk of composite adverse neonatal outcome (OR1.68, 95% CI 1.25-2.24, p &lt; 0.001) compared with primary MSAF.

CONCLUSIONS

In this sample, secondary MSAF was associated with more adverse neonatal outcomes than primary MSAF. Closer monitoring of fetal well-being may be prudent in these cases.

Meconium Aspiration Syndrome in Animal Models: Inflammatory Process, Apoptosis, and Surfactant Inactivation

Meconium Aspiration Syndrome is a condition that causes respiratory distress in newborns due to occlusion and airway inflammation, and surfactant inactivation by meconium. This condition has been described in animal species such as canids, sheep, cattle, horses, pigs, and marine mammals. In its pathogenesis, the pulmonary epithelium activates a limited inflammatory response initiated by cytokines causing leukocyte chemotaxis, inhibition of phagocytosis, and pathogen destruction. Likewise, cytokines release participates in the apoptosis processes of pneumocytes due to the interaction of angiotensin with cytokines and the caspase pathway. Due to these reactions, the prevalent signs are lung injury, hypoxia, acidosis, and pneumonia with susceptibility to infection. Given the importance of the pathophysiological mechanism of meconium aspiration syndrome, this review aims to discuss the relevance of the syndrome in veterinary medicine. The inflammatory processes caused by meconium aspiration in animal models will be analyzed, and the cellular apoptosis and biochemical processes of pulmonary surfactant inactivation will be discussed.

Contemporary management of infants born through meconium stained amniotic fluid

Delivery room management of infants delivered through meconium stained amniotic fluid has evolved over the past four decades. The burden of disease weighs more heavily in low- and middle-resource areas. Current information does not allow for precise prediction of infants that will require resuscitation at delivery versus those that need simple stabilization. Optimal care of newborns requires assessment of risk factors and obstetrical and pediatric team preparation to respond to the needs of the newborn.

Determinants of Meconium-Stained Amniotic Fluid at Hadiya Zone Hospitals, Southern Ethiopia; Unmatched Case-Control Study

Background

Meconium-stained amniotic fluid (MSAF) refers to an amniotic fluid that is green in color or mixed with meconium. MSAF leads to a serious maternal complication that increases the likelihood of operative delivery and poses a hazard to the fetus or the neonate. This in turn enhances the chances of maternal and neonatal mortality and morbidity. So, the identification of determinants helps to breach this vicious cycle. The current study aimed to assess the determinants of MSAF.

Methods

An institution-based, unmatched case-control study with a sample size of 363 participants (121 cases and 242 controls) was conducted on mothers who gave birth at Hadiya zone public hospitals between March and April 2020. A proportionate distribution was made to each facility depending on the volume of patients, and cases and control mothers were chosen sequentially. The data was gathered through in-person interviews and secondary data extraction. In multivariable logistic regression, variables with (p < 0.25) in bivariate analysis were included. After multivariable logistic regression was finished, statistical significance was declared at (p < 0.05).

Results

A total of 121 cases and 242 controls were included in this study Multivariable logistic regression analysis showed that gestational age ≥ 41 week (AOR = 3.44, 95% CI: 1.02–11.63), premature rupture of membrane (AOR = 3.71, 95% CI: 1.98–6.93) obstructed labor (AOR = 2.90, 95% CI: 1.15–7.33) preeclampsia (AOR = 4.16, 95% CI: 1.29–13.35) and non-reassuring fetal heart rate (AOR = 6.75, 95% CI: 3.45–13.19) were significantly associated with MSAF.

Conclusion

Advanced gestational age, an early membrane rupture, an obstructed labor, preeclampsia, and non-reassuring fetal heart rate all increase the incidence of meconium-stained amniotic fluid in laboring mothers. Making every effort to prevent, identify, and treat those obstetric determinants as early as feasible should be taken into consideration throughout follow-up of pregnancy, labor, and delivery could assist to lower the incidence of MSAF.

Prise en charge périnatale du nouveau-né lors d’une naissance en milieu extrahospitalier

Les accouchements inopinés extrahospitaliers représentent environ 0,3 % des accouchements en France. La prise en charge du nouveau-né en préhospitalier par une équipe Smur fait partie de l’activité courante. L’évaluation initiale du nouveau-né comprend systématiquement la mesure de sa fréquence cardiaque (FC) et respiratoire (FR), l’appréciation de son tonus ainsi que la mesure de sa température axillaire. En cas de doute ou de transition incomplète un monitoring cardiorespiratoire sera immédiatement mis en place (FC, FR, SpO2). Nous faisons ici une mise au point sur les données connues et avons adapté les pratiques, si besoin, au contexte extrahospitalier, car la majeure partie des données rapportées dans la littérature concernent les prises en charge en maternité ou en milieu hospitalier. Nous abordons les points essentiels de la prise en charge des nouveau-nés, à savoir la réanimation cardiopulmonaire, le clampage tardif du cordon ombilical, la lutte contre l’hypothermie et l’hypoglycémie; ainsi que des situations particulières comme la prématurité, la conduite à tenir en cas de liquide méconial ou de certaines malformations congénitales. Nous proposons aussi quels peuvent être : le matériel nécessaire à la prise en charge des nouveau-nés en extrahospitalier, les critères d’engagement d’un renfort pédiatrique à la régulation ainsi que les méthodes de ventilation et d’abord vasculaire que l’urgentiste doit maîtriser. L’objectif de cette mise au point est de proposer des prises en charge les plus adaptées au contexte préhospitalier.

The evaluation of the antepartum and intrapartum risk factors in predicting the risk of birth asphyxia

PURPOSE

This study aimed to determine the related antepartum and intrapartum factors of birth asphyxia among neonates born in a tertiary referral hospital.

METHODS

A total of 45 singleton pregnant women who delivered live births with a gestational age of ≥35 weeks and their neonates who suffered from birth asphyxia from June 2016 to June 2021 were included in this retrospective study. Data regarding maternal demographic features, maternal laboratory values, pregnancy complications, and obstetric and neonatal outcomes were collected.

RESULTS

Significant risk factors associated with birth asphyxia were nulliparity (odds ratio [OR] = 5.357, 95% confidence interval [CI] = 2.169-24.950, p = 0.001), placental abruption (OR = 8.667, 95% CI = 2.223-33.784, p = 0.002), intrauterine growth restriction (OR = 1.394, 95% CI = 1.109-8.631, p = 0.012), the prolonged second stage of labor (OR = 6.121, 95% CI = 2.120-17.595, p = 0.001), meconium-stained amniotic fluid (OR = 7.615, 95% CI = 2.394-24.223, p = 0.001), bloody amniotic fluid (OR = 9.423, 95% CI = 2.885-35.232, p = 0.001), the presence of FHR category II (OR = 12.083, 95% CI = 7.081-48.849, p <0.001) and FHR category III before labor (OR = 15.500, 95% CI = 8.394-56.176, p <0.001).

CONCLUSION

We identified that nulliparity, placental abruption, intrauterine growth restriction, the prolonged second stage of labor, meconium-stained or bloody amniotic fluid, and FHR tracings categories II and III were significantly associated with birth asphyxia.

Incidental finding of meconium-stained amniotic fluid in elective cesarean deliveries: Features and perils

OBJECTIVE

To characterize pregnancies in which meconium-stained amniotic fluid (MSAF) was incidentally discovered during elective caesarean delivery (CD), and to evaluate the association with adverse neonatal outcomes.

METHODS

A retrospective study was performed on all patients who underwent elective CD with singleton pregnancies between March 2011 and June 2020. Data analyzed included maternal, pregnancy, and neonatal characteristics. A comparison was made between pregnancies with clear amniotic fluid, MSAF, and thick MSAF.

RESULTS

During the study period, 10 445 patients with singleton pregnancies underwent elective CD. Of them, 368 (3.5%) had MSAF and 31 (0.3%) had thick MSAF. Patients with MSAF gained more weight during pregnancy and suffered more from diabetes compared with patients with clear fluid. Significantly more pregnancies with MSAF had either oligohydramnios or polyhydramnios. Pregnancies in the thick-MSAF group had more intrahepatic cholestasis of pregnancy. No differences were found between the groups in the composite adverse neonatal outcome, including 5-min Apgar score, need for mechanical ventilation, and admission to the neonatal intensive care unit.

CONCLUSION

The incidental finding of MSAF during elective CD is not associated with increased risks of adverse neonatal outcomes.

Meconium-stained amniotic fluid and histologic signs of fetal distress in stillbirths

OBJECTIVE

Stillbirth is one of the most devastating adverse pregnancy outcome, but it is often associated with a missing post-mortem histological examination. We aimed at evaluating whether the staining of amniotic fluid reflects the fetal conditions surrounding the death and if it correlates with any histologic sign of fetal distress.

STUDY DESIGN

Terminal gasping (represented by the massive presence of intra-alveolar squamous cells), thymic and adrenal cortex modifications were evaluated as histologic signs of fetal distress in stillbirths, and stratified according to the degree of staining of the amniotic fluid.

RESULTS

The presence of meconium-stained amniotic fluid did not correlate with the presence of gasping and/or thymic and/or adrenal cortex changes. Clear amniotic fluid was not associated with the absence of histologic signs of distress.

CONCLUSIONS

The evaluation of the staining of the amniotic fluid fails to identify distressed fetuses. A histologic evaluation of fetal organs provides detailed information, irrespective of the presence/absence of meconium-stained amniotic fluid.

Choosing placental hypoxic-ischemic measures that have clinical implications in child development and diseases

PURPOSE

Placental hypoxic-ischemic pathology is one of the common causes for adverse outcomes. But there is no commonly accepted evaluation system on specific morphological and histopathological measures of the placenta.

OBJECTIVE

This study aims to systematically select several core placental hypoxic-ischemic measures that have a high prognostic relevance to child health.

METHODS

We used data from the Collaborative Perinatal Project, a multicenter prospective cohort study that recruited over 55,000 pregnant women and followed their offspring to 7 years old. Women who had information on placental pathology and child outcomes were included. 57 placental measures considered to be relevant to hypoxia-ischemia were selected. Apgar score, intelligence quotient, preeclampsia, birth weight and subclinical neurology injuries were chosen as outcomes. The least absolute shrinkage and selection operator (LASSO) procedure as well as training and testing methods were used to select a more efficient and simpler placental hypoxic-ischemic measures that may have clinical implications.

RESULTS

Of the 57 measures, 7 were selected as candidates by LASSO. Based on the training and testing methods, we retained placental measures with a higher odds ratio of child morbidity. We further narrowed down to four measures that had the highest prognostic relevance. They were: short cord length (ΣOR = 8.51), calcification of cut surface (ΣOR = 8.31), opaque membranes (ΣOR = 5.26), Hofbauer cells in terminal villi (ΣOR = 4.69).

CONCLUSIONS

Our four-measure system is relatively simple and closely related to the child health. It may be used as a novel placental hypoxic-ischemic evaluation criterion, and function as the first line tool for future research.

Management of Intrahepatic Cholestasis of Pregnancy: Recommendations of the Working Group on Obstetrics and Prenatal Medicine - Section on Maternal Disorders

Intrahepatic cholestasis of pregnancy (ICP) is the most common liver disease specific to pregnancy. The cardinal symptom of pruritus and a concomitant elevated level of bile acids in the serum and/or alanine aminotransferase (ALT) are suggestive for the diagnosis. Overall, the maternal prognosis is good. The fetal outcome depends on the bile acid level. ICP is associated with increased risks for adverse perinatal outcomes, including preterm delivery, meconium-stained amniotic fluid, and stillbirth. Acute fetal asphyxia and not chronic uteroplacental dysfunction leads to stillbirth. Therefore, predictive fetal monitoring is not possible. While medication with ursodeoxycholic acid (UDCA) improves pruritus, it has not been shown to affect fetal outcome. The indication for induction of labour depends on bile acid levels and gestational age. There is a high risk of recurrence in subsequent pregnancies.

Meconium stained amniotic fluid exposure and long-term respiratory morbidity in the offspring

OBJECTIVE

Meconium stained amniotic fluid (MSAF) is a well-established risk factor for neonatal short-term respiratory complications. Little is known regarding the long-term morbidity. We investigated the possible association between MSAF and offspring respiratory morbidity.

METHODS

A population-based, cohort study of singleton deliveries occurring between 1991 and 2014 at a sole regional tertiary medical center was performed. Incidence of offspring respiratory related hospitalizations up to the age of 18 years were evaluated and compared to unexposed offspring. A Kaplan-Meier survival curve was used to compare cumulative respiratory morbidity incidence, and a Cox proportional hazards model was used to control for confounders.

RESULTS

During the study period 242,342 deliveries met the inclusion criteria. Of them, 14.7% (n = 35,609) were complicated with MSAF. Incidence of respiratory-related hospitalizations was significantly lower in children exposed to MSAF as compared to the unexposed group (4.5% vs. 4.9%, respectively; p < .01). Specifically, hospitalizations involving pneumonitis were significantly less common among the MSAF group (odds ratio, 0.35; 95% confidence interval [95% CI], 0.13-0.96; p = .03). The Kaplan-Meier survival curve demonstrated significantly lower total cumulative respiratory morbidity rates in the MSAF exposed group (log rank p < .01). In the Cox model, controlled for clinically relevant confounders, MSAF exhibited an independent and significant protective effect on long-term childhood respiratory morbidity (aHR, 0.91; 95% CI, 0.86-0.96; p < .01).

CONCLUSIONS

Fetal exposure to MSAF during labor appears to be associated with lower rates of long-term respiratory related hospitalizations in the offspring. Changes in offspring microbiome, as well as functional and anatomical modulations possibly resulting from MSAF exposure, might offer a plausible explanation of our findings.

Is meconium exposure associated with autism spectrum disorders in children?

BACKGROUND

The results differ among published studies regarding exposure to meconium and the risk of developing autism spectrum disorders (ASDs).

PURPOSE

The present study pooled all of the epidemiologic studies retrieved from broader databases on the association between meconium exposure and risk of developing ASD in children.

METHODS

The Web of Science, PubMed, Scopus, and Google Scholar databases were searched without language restrictions for articles published between their inception to February 20, 2020, using relevant keywords. The pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated as random-effect estimates of the associations among studies. A subgroup analysis was conducted to explore any potential sources of heterogeneity among studies.

RESULTS

The pooled estimate of OR reported a weakly significant association between meconium exposure and ASD development in children (OR, 1.13; 95% CI, 1.03-1.24). There was low heterogeneity among the articles reporting risk for ASD among children (I2=19.3%; P=0.259). The results of subgroup analysis based on meconium exposure showed a significant association between a meconium-stained neonate and ASD development (OR, 1.18; 95% CI, 1.11-1.24).

CONCLUSION

Meconium exposure was weakly associated with an increased risk of ASD. However, more evidence based on large prospective cohort studies is required to provide conclusive evidence about whether meconium exposure is associated with an increased risk of ASD development.

Time needed to intubate and suction a manikin prior to instituting positive pressure ventilation: a simulation trial

Tracheal suctioning in non-vigorous newborn delivered through meconium-stained amniotic fluid (MSAF) is supposed to delay initiation of positive pressure ventilation (PPV), but the magnitude of such delay is unknown. To compare the time of PPV initiation when performing immediate laryngoscopy with intubation and suctioning vs. performing immediate PPV without intubation in a manikin model. Randomized controlled crossover (AB/BA) trial comparing PPV initiation with or without endotracheal suctioning in a manikin model of non-vigorous neonates born through MSAF. Participants were 20 neonatologists and 20 pediatric residents trained in advanced airway management. Timing of PPV initiation was longer with vs. without endotracheal suctioning in both pediatric residents (mean difference 13 s, 95% confidence interval 8 to 18 s; p < 0.0001) and neonatologists (mean difference 12 s, 95% confidence interval 8 to 16 s; p < 0.0001). The difference in timing of PPV initiation was similar between pediatric residents and neonatologists (mean difference - 1 s, 95% confidence interval - 7 to 6 s; p = 0.85).Conclusions: Performing immediate laryngoscopy with intubation and suctioning was associated with longer-but not clinically relevant-time of initiation of PPV compared with immediate PPV without intubation in a manikin model. While suggesting negligible delay in starting PPV, further studies in a clinical setting are warranted.Registration: clinicaltrial.gov NCT04076189. What is Known: • Management of the non-vigorous newborn delivered through meconium-stained amniotic fluid remains still controversial. • Tracheal suctioning in non-vigorous newborn delivered through meconium-stained amniotic fluid is supposed to delay initiation of positive pressure ventilation, but the magnitude of such delay is unknown. What is New: • Performing immediate ventilation without intubation was associated with shorter-but not clinically relevant-time of initiation of ventilation compared to immediate laryngoscopy with intubation and suctioning in a manikin model. • Further studies in a clinical setting are warranted.

Perinatal outcome of meconium stained amniotic fluid among labouring mothers at teaching referral hospital in urban Ethiopia

Objective

To determine the perinatal outcome of labouring mothers with meconium-stained amniotic fluid (MSAF) compared with clear amniotic fluid at teaching referral hospital in urban Ethiopia.

Methods

A prospective cohort study was conducted among labouring mothers with meconium-stained amniotic fluid from July 1 to December 30, 2019. Data was collected with pretested structured questionnaires. A Chi-square test used to check statistical associations between variables. Those variables with a p-value of less than 0.05 were selected for cross-tabulation and binary logistic regression. P-value set at 0.05, and 95% CI was used to determine the significance of the association. Relative risk was used to determine the strength and direction of the association.

Result

Among 438 participants, there where 75(52.1%) primigravida in a stained fluid group compared to112 (38.5%) of the non-stained fluid group. Labour was induced in 25 (17.4%) of the stained fluid group compared to 25(8.6%) of a non-stained fluid group and has a statistically significant association with meconium staining. The stained fluid group was twice more likely to undergo operative delivery compared with a non-stained fluid group. There were more low Apgar scores at birth (36.8% versus 13.2%), birth asphyxias (9% versus 2.4%), neonatal sepsis (1% versus 5.6%), neonatal death (1% versus 9%), and increased admissions to neonatal intensive care unit (6.2% versus 21.5%) among the meconium-stained group as compared to the non-stained group. Meconium aspiration syndrome was seen in 9(6.3%) of the stained fluid group.

Conclusion

Meconium-stained amniotic fluid is associated with increased frequency of operative delivery, birth asphyxia, neonatal sepsis, and neonatal intensive care unit admissions compared to clear amniotic fluid.

Placental histology of acute versus continuous meconium exposure - Association with obstetric and neonatal outcomes

OBJECTIVE

We aimed to compare obstetric and neonatal outcomes of deliveries complicated by meconium stained amniotic fluid (MSAF), according to placental histology of continuous vs. acute meconium associated changes.

METHODS

This was a retrospective cohort study of singleton deliveries complicated by MSAF at a single university-affiliated medical center during 2008-2018. Obstetric and neonatal outcomes were compared between cases with placental acute vs. continuous meconium exposure associated changes (columnar epithelial changes and meconium-laden macrophages, respectively). Regression analysis was used to identify independent associations with adverse neonatal outcomes.

RESULTS

The medical records of 294 deliveries at our institution were reviewed, along with medical records of the neonates and the histopathological reports of their placentas. Ninety-two cases were classified as an acute placental reaction to meconium (acute exposure group) and 200 as continuous placental exposure (continuous exposure group). Patient demographics did not differ between groups. Placentas from the continuous exposure to meconium were associated with a higher rate of placental weight <10th percentile (p = 0.03) while the acute exposure group was associated with a shorter time between rupture of membranes and delivery (p = 0.02). and higher rates of non-reassuring fetal heart rate in labor (p = 0.003), and of adverse neonatal outcome (p = 0.02). In multivariable analysis adverse neonatal outcome was associated with acute histologic exposure to meconium independent of background confounders (aOR = 1.51, 95% CI 1.12-3.67).

CONCLUSIONS

Acute histological changes of MSAF were independently associated with adverse neonatal outcomes as compared to continuous histologic MSAF.

Postpartum urinary retention: Absolute risk prediction model

OBJECTIVES

To evaluate the incidence and assess clinical factors that can predict the occurrence of postpartum urinary retention (PPUR). PPUR is a puerperal condition defined as the inability to void over 6 hours after birth or after catheter removal in case of cesarean section, requiring catheterization. Lack of prompt diagnosis of this condition may lead to severe sequelae, including infection, chronic voiding difficulties, and renal failure.

METHODS

This retrospective cohort study analyzed all deliveries from January 2011 to December 2017 in a single Italian university hospital. We used multivariate logistic regression to develop a predictive score for PPUR.

RESULTS

By multivariate logistic regression, our analysis shows as minor (odds ratio [OR] < 2) risk factors for PPUR: non-Caucasian ethnicity (OR = 1.46, CI = 1.05-2.03), nulliparity (OR = 1.47, CI = 1.01-2.14), body mass index (BMI) at the end of the pregnancy <30 kg/m² (OR = 1.54, CI = 1.10-2.17). On the other hand, epidural analgesia (OR = 3.93, CI = 2.96-5.22), meconium-stained amniotic fluid (OR = 2.07, CI = 1.54-2.77), nonoperative vaginal birth vs cesarean section (OR = 6.25, CI = 2.16-18.13), vacuum extraction vs cesarean section (OR = 8.80, CI = 2.86-27.01), pushing stage ≥60 minutes (OR = 3.00,CI = 2.26-3.97), and perineal tear (OR = 2.87, CI = 1.86-4.43) proved to be major (OR > 2) risk factors for PPUR. Using our final model (area under curve = 0.84), we created a nomogram for PPUR absolute risk calculation. Specifically, a 116-point cutoff might be used to identify high-risk patients who deserve more intensive micturition monitoring.

CONCLUSIONS

Our study identified non-Caucasian ethnicity, nulliparity, and a BMI <30 kg/m² at the end of the pregnancy as minor and epidural analgesia, meconium-stained amniotic fluid, vaginal nonoperative birth, vacuum extraction, pushing stage ≥60 minutes, and perineal tear as major independent risk factors for PPUR.

Typical general movements at 2 to 4 months: Movement complexity, fidgety movements, and their associations with risk factors and SINDA scores

BACKGROUND

Movement complexity and the presence of fidgety movements (FMs) during general movements (GMs) both reflect aspects of neurological integrity in early infancy.

AIM

To assess interrelations between the degree of movement complexity and characteristics of FMs during typical GMs and to investigate associations between mildly impaired GMs and risk factors and neurodevelopmental condition.

STUDY DESIGN

Observational cohort study.

SUBJECTS

283 infants (25 born preterm) at 2-4 months corrected age, representative of the general Dutch population.

OUTCOME MEASURES

GMs were classified in terms of GM-complexity (normal or mildly abnormal (MA)) and FMs (clearly present, sporadic, or exaggerated). Concurrent neurological, developmental and socio-emotional status were measured with the Standardized Infant NeuroDevelopmental Assessment (SINDA).

RESULTS

Infants with MA GM-complexity had a higher risk of having sporadic FMs and exaggerated FMs. Perinatal complications were not associated with mildly impaired GMs. MA GM-complexity was associated with advanced maternal age (adjusted OR = 2.29 [1.11, 4.76]) and having a non-native Dutch mother (adjusted OR = 2.93 [1.29, 6.64]). It was also associated with atypical neurological (OR = 7.62 [3.51, 16.54]) and developmental scores (OR = 2.38 [1.16, 4.88]). Sporadic and exaggerated FMs were associated with low-to-middle maternal education (adjusted OR = 2.88, [1.45, 5.72]) and having a non-native Dutch father (adjusted OR = 7.16 [1.41, 36.32]), respectively. However, neither sporadic nor exaggerated FMs were associated with the SINDA outcomes.

CONCLUSIONS

GM-complexity and FMs are two interrelated but different aspects of GMs. Mild impairments in GM-complexity and FMs share a non-optimal socio-economic background as risk factor, but only MA GM-complexity is associated with a concurrent non-optimal neurodevelopmental condition.

Umbilical cord arterial blood gas analysis in term singleton pregnancies: a retrospective analysis over 11 years

Objective

Given that the large volume of data on cord arterial blood gas analysis (ABGA) have been rarely addressed in Korean population, we aimed to examine the incidence, associated factors, and neonatal outcomes in cases of low cord pH, and investigate the incidence of cerebral palsy (CP).

Methods

From data of all consecutive term singleton pregnancies delivered in our institution from 2006 to 2016 (n=15,701), cases with cord ABGA (n=14,221) available were included. We collected information on maternal clinical characteristics and delivery outcomes and also examined neonatal and infant outcomes, including neonatal intensive care unit (NICU) admission and CP, in cases with low cord pH, defined as a pH <7.1.

Results

Rates of low Apgar scores at 1 minute (<4) and 5 minutes (<7) were 0.6% (n=79) and 0.4% (n=58), respectively. Rates of cord pH <7.2, <7.1, and <7.0 were 7.1% (n=1,011), 1.1% (n=163), and 0.3% (n=38), respectively. Among cases with low cord pH, 30.1% (n=49/163) were admitted to the NICU and 11.0% (n=18/163) required ventilator support. Ultrasonography of the brain was performed in 28.8% (n=47/163), with abnormal findings observed in 27.7% (n=13/47). Among cases with low cord pH, 1.8% (n=3/163) were subsequently diagnosed with CP, including 2 cases of spastic CP and 1 of ataxic CP.

Conclusion

Although low cord pH was a relatively frequent finding observed in 1 out of every 87 cases, hypoxic-ischemic encephalopathy-related CP was found in only 1 out of 7,111 term singleton deliveries over 11 years in our institution.

Delivery mode and maternal and neonatal outcomes of combined spinal-epidural analgesia compared with no analgesia in spontaneous labor: A single-center observational study in Japan

AIM

We aimed to assess the outcomes of combined spinal-epidural (CSE) analgesia compared with no analgesia in spontaneous labor.

METHODS

We performed a retrospective cohort study of deliveries between 2008 and 2014 comparing two groups based on the use of CSE analgesia in both nulliparous and multiparous women. Adjusted odds ratios (aOR) were calculated using logistic regression analysis.

RESULTS

Among 5247 (3334 nulliparous, 1913 multiparous) singleton deliveries, 3041 (2045, 996, respectively) patients received CSE analgesia and 2206 (1289, 917, respectively) had no analgesia. CSE analgesia was associated with increased risk of oxytocin augmentation (P < 0.01), prolonged duration of labor (P < 0.01), instrumental delivery (aOR, 3.35; 95% confidence interval (CI), 2.69-4.19 for nulliparous and aOR, 2.13; 95% CI, 1.32-3.53 for multiparous women), blood loss volume during vaginal delivery (P < 0.01), meconium-stained amniotic fluid (aOR, 1.23; 95% CI, 1.02-1.51 and aOR, 1.39; 95% CI, 1.01-1.93) and Apgar score less than 7 at 1 min (aOR, 1.85; 95% CI, 1.28-2.74 and aOR, 2.65; 95% CI, 1.35-5.61) in both nulliparous and multiparous women, respectively, and umbilical arterial blood gas pH less than 7.15 (aOR, 2.69; 95% CI, 1.35-5.75) and umbilical arterial blood gas pH less than 7.10 (aOR, 3.69; 95% CI, 1.11-16.69) in multiparous women. There was no significant difference in incidence of cesarean delivery or Apgar score less than 7 at 5 min.

CONCLUSION

We observed several increased risks in obstetric and neonatal outcomes among pregnant women who received CSE analgesia during labor. Preparations for these risks are needed when administering CSE analgesia during labor.

Effectiveness of high-frequency oscillatory ventilation for the treatment of neonatal meconium aspiration syndrome

BACKGROUND

The purpose of this study is to raise nonjudgmental awareness and attention to current experience of high-frequency oscillatory ventilation (HFOV) for the treatment of neonatal meconium aspiration syndrome (NMAS).

METHODS

We will comprehensively search literature from the databases of Cochrane Library, PubMed, Embase, Web of Science, WorldSciNet, PsycINFO, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure from inception until July 1, 2019 without language limitation. We will also handle searching the bibliographies of all relevant studies found for unpublished literatures. Statistical analysis will be conducted using RevMan 5.3 software.

RESULTS

The outcomes include function inhaled oxygen concentration, oxygenation index, arterial oxygen tension/alveolar arterial oxygen tension, partial pressure of oxygen, partial pressure of carbon dioxide, transcutaneous arterial oxygen saturation, duration of hospitalization, and adverse events.

CONCLUSION

This study will provide an exhaustive view of HFOV for treating infants with NMAS.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019140520.

Meconium-stained amniotic fluid and the risk of postcesarean surgical site infection

OBJECTIVE

To investigate the association between meconium-stained amniotic fluid (MSAF) and postcesarean surgical site infections.

METHODS

This was a secondary analysis of the Maternal-Fetal Medicine Units Network (MFMU) Cesarean Registry. Women with a singleton pregnancy attempting labor or induction of labor, who ultimately had a cesarean delivery, were included in the study. Pregnancies complicated by MSAF (n = 4262) and those who did not have MSAF (n = 13,850) were compared. The primary outcome was the incidence of SSI.

RESULTS

A total of 18,112 patients were included in the study. 4262 (38%) had meconium-stained amniotic fluid. After accounting for potential confounders in a multivariable logistic regression, meconium-stained amniotic fluid was associated with an increased risk of postoperative surgical site infection (odds ratio 1.16, 95% CI 1.03-1.30).

CONCLUSIONS

Meconium-stained amniotic fluid may be associated with an increased risk of postoperative surgical site infection.

Meconium-stained amniotic fluid exposure is associated with a lower incidence of offspring long-term infectious morbidity

OBJECTIVE

Meconium-stained amniotic fluid (MSAF) is a well-established risk factor for immediate adverse neonatal outcomes and was recently suggested to be associated with microbial invasion of the amniotic cavity. We aimed to determine whether MSAF exposure during labor carries a longer lasting impact on pediatric infectious morbidity.

STUDY DESIGN

A population-based cohort analysis was performed including all singleton deliveries occurring between 1991 and 2014 at a single tertiary medical center. Exposure was defined as the presence of MSAF during labor. Hospitalizations of the offspring up to the age of 18 years involving infectious diseases were evaluated. A Kaplan-Meier survival curve was used to compare cumulative morbidity and a Cox regression model to control for confounders.

RESULTS

During the study period, 243 725 deliveries met the inclusion criteria. Of them, 35 897 (14.7%) involved MSAF. Rate of infectious-related hospitalizations of the offspring was significantly lower in children exposed to MSAF as compared with the unexposed group (10.8% vs 11.1%, P < 0.05). Specifically, hospitalizations involving respiratory infections were significantly less common among the MSAF group (5.1% vs 5.6%, P < 0.001). The survival curve demonstrated significantly lower cumulative total infectious morbidity rates in the MSAF-exposed group (log rank P < 0.001). In the Cox model, controlled for maternal age, diabetes, hypertension, mode of delivery, and gestational age, exposed children exhibited lower rates of long-term childhood infectious morbidity (adjusted HR 0.96, 95% CI 0.92-0.99, P < 0.001).

CONCLUSION

Fetal exposure to MSAF during labor and delivery appears to be associated with lower rates of long-term infectious-related hospitalizations in the offspring.

Meconium aspiration pneumonia and otitis media in two goat kids

We report meconium aspiration in 2 sibling goat kids, and characterize the expected lesions of aspiration pneumonia in conjunction with the rare lesion of otitis media. Grossly, the lungs were multifocally consolidated, and there was yellow-green exudate within the middle ear. Histologically, the lung was characterized by pyogranulomatous pneumonia and foreign-body reaction around aspirated debris. Within the lumen of the middle ear, aspirated squamous cells, keratin, meconium debris, and neutrophils, without evidence of bacteria, were accompanied by a subepithelial accumulation of lymphocytes, plasma cells, and fewer macrophages. This is an especially rare phenomenon, which is thought to result from transport of meconium from the oropharynx through the auditory tube (Eustachian tube) to the middle ear.

Pneumonia

Neonatal pneumonia may occur in isolation or as one component of a larger infectious process. Bacteria, viruses, fungi, and parasites are all potential causes of neonatal pneumonia, and may be transmitted vertically from the mother or acquired from the postnatal environment. The patient's age at the time of disease onset may help narrow the differential diagnosis, as different pathogens are associated with congenital, early-onset, and late-onset pneumonia. Supportive care and rationally selected antimicrobial therapy are the mainstays of treatment for neonatal pneumonia. The challenges involved in microbiological testing of the lower airways may prevent definitive identification of a causative organism. In this case, secondary data must guide selection of empiric therapy, and the response to treatment must be closely monitored.

Relationship between early onset severe intrahepatic cholestasis of pregnancy and higher risk of meconium-stained fluid

Background

Intrahepatic cholestasis of pregnancy (ICP) is the commonest gestational liver disease. The risk of adverse fetal outcome has been associated with the severity of maternal hypercholanemia after diagnosis.

Objective

To investigate whether there is a relationship between the severity and timing of onset of hypercholanemia and the risk of meconium-stained amniotic fluid (MSAF) and adverse neonatal events.

Study design

The study included 382 pregnancies complicated by ICP managed at a referral hospital in Buenos Aires (Argentina) between June 2009 and December 2013. The patients were classified into three groups according to the severity of hypercholanemia at diagnosis; mild (10–19.9 μmol/L), moderate (20–39.9 μmol/L) and severe (≥40 μmol/L). Their clinical characteristics and pregnancy outcomes were investigated in a prospective observational study.

Results

Higher risk of MSAF was observed when ICP appeared early in gestation or when hypercholanemia was more severe. Taking both parameters into account an MSAF risk factor (MRF) was defined. Based on a model of positive/negative predictive values, a cut-off point of MRF = 3 was selected, which prioritized sensitivity versus specificity. In ICP patients with MRF>3, the probability of MSAF was enhanced 4-fold. An increase in the frequency of MSAF was also associated with higher serum levels at diagnosis of alanine transaminase, alkaline phosphatase and direct bilirubin.

Conclusions

The risk of MSAF is associated not only with the magnitude of hypercholanemia at diagnosis but also with the early gestational onset of raised maternal serum bile acids.

Restoring pulmonary surfactant membranes and films at the respiratory surface

Pulmonary surfactant is a complex of lipids and proteins assembled and secreted by the alveolar epithelium into the thin layer of fluid coating the respiratory surface of lungs. There, surfactant forms interfacial films at the air-water interface, reducing dramatically surface tension and thus stabilizing the air-exposed interface to prevent alveolar collapse along respiratory mechanics. The absence or deficiency of surfactant produces severe lung pathologies. This review describes some of the most important surfactant-related pathologies, which are a cause of high morbidity and mortality in neonates and adults. The review also updates current therapeutic approaches pursuing restoration of surfactant operative films in diseased lungs, mainly through supplementation with exogenous clinical surfactant preparations. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.

Meconium exposure and autism risk

OBJECTIVE

This study aims to determine whether fetal meconium passage is associated with autism.

STUDY DESIGN

This retrospective birth cohort analysis of 9 945 896 children born in California 1991 to 2008 linked discharge diagnosis and procedure codes for prenatal stressors, meconium-stained amniotic fluid (MSAF) and meconium aspiration syndrome (MAS) with autism diagnoses for 47 277 children through 2012. We assessed the relative risk of autism by meconium status using logistic regression, adjusting for demographic and clinical features.

RESULTS

Children exposed to meconium (MSAF and MAS) were more likely to be diagnosed with autism in comparison with unexposed children (0.60% and 0.52%, vs 0.47%, respectively). In adjusted analyses, there was a small increase in autism risk associated with MSAF exposure (adjusted relative risk (aRR) 1.18, 95% confidence interval (CI) 1.12 to 1.25), and a marginal association that failed to achieve significance between MAS and autism (aRR 1.08, 95% CI 0.98 to 1.20).

CONCLUSION

Resuscitation of neonates with respiratory compromise from in utero meconium exposure may mitigate long-term neurodevelopmental damage.

Is the neonatal creatine phosphokinase level a reliable marker for fetal hypoxia?

AIM

The creatine phosphokinase (CPK) level is believed to increase in neonatal peripheral blood after tissue damage, including damage from perinatal hypoxia. However, it is not clear whether it is truly a reliable marker for fetal hypoxia. We investigated the chronological changes in neonatal CPK and the reliability of CPK as a marker for fetal hypoxia.

METHODS

Sixty term neonates admitted to the neonatal intensive care unit at Tokyo Women's Medical University Medical Center East from April 2009 to April 2010 were enrolled in this study. We evaluated whether asphyxia and fetal heart rate (FHR) abnormality could predict the neonatal CPK level by using receiver-operator curve analysis. We also compared umbilical cord blood pH levels with neonatal CPK levels. In addition, we investigated factors that influence neonatal CPK in non-asphyxia cases.

RESULTS

The median value of CPK peaked on day 1. There were no significant differences in CPK levels regardless of the presence of asphyxia or FHR abnormality. Non-asphyxiated neonates with older gestational ages and amniotic fluid abnormalities had significantly higher levels of CPK.

CONCLUSION

Our results indicate that the neonatal CPK level is not an appropriate marker for retrospectively predicting either asphyxia or FHR abnormality. There are influencing factors other than asphyxia that increase neonatal CPK. Therefore, one should be careful when making a diagnosis of perinatal hypoxia based solely on increased levels of neonatal CPK after birth.

Stillbirth and intrauterine fetal death: role of routine histological organ sampling to determine cause of death

OBJECTIVES

Guidelines for the investigation of intrauterine death and sudden unexpected death in infancy (SUDI) recommend, based on expert opinion, autopsy procedures and tissue sampling strategies for histological analysis. Although stillbirth is much more common than SUDI, there have been no large-scale studies published which evaluate the usefulness of histological evaluation of specific organs in stillbirth for determining cause of death. Our aim was to evaluate the use of macroscopic and microscopic assessment of internal organs to determine cause of intrauterine death.

METHODS

As part of a larger study evaluating several aspects of autopsy findings in intrauterine death, a dedicated database was used to collate antenatal and postmortem examination details for cases of intrauterine death examined between 2005 and 2013 at two tertiary specialist centers in London, UK. Histological findings for all organs were examined in relation to the final cause of death, as determined by objective criteria.

RESULTS

Among 1064 intrauterine deaths, the majority (> 80%) of cases had internal organs that were normal on both macroscopic and microscopic examination. There was no case in which histological cardiac examination provided the cause of death when the macroscopic appearance of the heart was normal. Microscopic examination of lung tissue revealed 13 (1%) cases with histological abnormalities that provided the cause of death when the macroscopic appearance was normal, but there was only one (0.1%) case in which the diagnosis would not have been apparent on placental examination: a case of congenital cytomegalovirus infection. There was no case in which microscopic examination of macroscopically normal liver, kidneys, adrenals, spleen, thymus, intestines, pancreas, brain or thyroid provided the cause of death.

CONCLUSION

In this large series of autopsies in cases of intrauterine death, only around 1% of cases demonstrated histological abnormalities which provided the cause of death when the internal organs appeared normal macroscopically. There was no case in which routine histological examination of most tissues provided diagnostically useful information that was not apparent from other examinations, such as placental pathology. There is little benefit, purely in terms of determining cause of death, in obtaining tissue from most macroscopically normal organs for routine histological examination. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Current Concepts in the Management of Meconium Aspiration Syndrome

In developing countries, meconium aspiration syndrome (MAS) is an important cause of morbidity and mortality among neonates. The concepts of pathophysiology and management of meconium stained amniotic fluid (MSAF) and meconium aspiration syndrome have undergone tremendous change in recent years. Routine intranatal and postnatal endotracheal suctioning of meconium in vigorous infants is no longer recommended. Recent studies have challenged its role even in non-vigorous infants. Supportive therapy like oxygen supplementation, mechanical ventilation and intravenous fluids are the cornerstone in the management of meconium aspiration syndrome. Availability of surfactant, inhaled nitric oxide, high frequency ventilators and extracorporeal membrane oxygenation has made it possible to salvage more infants with meconium aspiration syndrome. In this review the authors have discussed the current concepts in the pathophysiology and management of MAS. Drugs in trials and future therapeutic targets are also discussed briefly.

Meconium aspiration syndrome: a role for fetal systemic inflammation

BACKGROUND

Meconium aspiration syndrome (MAS) is a leading cause of morbidity and mortality in term infants. Meconium-stained amniotic fluid (MSAF) occurs in approximately 1 of every 7 pregnancies, but only 5% of neonates exposed to MSAF develop MAS. Why some infants exposed to meconium develop MAS while others do not is a fundamental question. Patients with MSAF have a higher frequency of intraamniotic inflammation/infection than those with clear fluid. We propose that fetal systemic inflammation is a risk factor for the development of MAS in patients with MSAF.

OBJECTIVE

We sought to investigate whether intraamniotic inflammation and funisitis, the histopathologic landmark of a fetal inflammatory response, predispose to MAS.

STUDY DESIGN

A prospective cohort study was conducted from 1995 through 2009. Amniotic fluid (AF) samples (n = 1281) were collected at the time of cesarean delivery from women who delivered singleton newborns at term (gestational age ≥38 weeks). Intraamniotic inflammation was diagnosed if the AF concentration of matrix metalloproteinase-8 was >23 ng/mL. Funisitis was diagnosed by histologic examination if inflammation was present in the umbilical cord.

RESULTS

The prevalence of MSAF was 9.2% (118/1281), and 10.2% (12/118) of neonates exposed to MSAF developed MAS. There were no significant differences in the median gestational age or umbilical cord arterial pH at birth between neonates who developed MAS and those who did not (each P > .1). Mothers whose newborns developed MAS had a higher median of AF matrix metalloproteinase-8 (456.8 vs 157.2 ng/mL, P < .05). Newborns exposed to intraamniotic inflammation had a higher rate of MAS than those who were not exposed to intraamniotic inflammation [13.0% (10/77) vs 0% (0/32), P = .03], as did those exposed to funisitis [31.3% (5/16) vs 7.3% (6/82); relative risk, 4.3; 95% confidence interval, 1.5-12.3]. Among the 89 newborns for whom both AF and placental histology were available, MAS was more common in patients with both intraamniotic inflammation and funisitis than in those without intraamniotic inflammation and funisitis [28.6% (4/14) vs 0% (0/28), P = .009], while the rate of MAS did not show a significant difference between patients with intraamniotic inflammation alone (without funisitis) and those without intraamniotic inflammation and funisitis [10.9% (5/46) vs 0% (0/28)].

CONCLUSION

The combination of intraamniotic inflammation with fetal systemic inflammation is an important antecedent of MAS. This concept has implications for the understanding of the mechanisms of disease responsible for MAS and for the development of prognostic models and therapeutic interventions for this disorder.