Elevated plasma corticotrophin release factor levels and in utero meconium passage

Magnitude of meconium stained amniotic fluid and associated factors among women who gave birth in North Shoa Zone hospitals, Amhara Region, Ethiopia 2022

BACKGROUND

The presence of meconium-stained amniotic fluid is one of the causes for birth asphyxia. Each year, over five million neonatal deaths occur worldwide because of meconium-stained amniotic fluid and other causes, of which 90% are due to birth asphyxia. The aim of this study was to assess the magnitude of meconium-stained amniotic fluid and associated factors among women who gave birth in North Shoa Zone Hospitals, Amhara Region, Ethiopia, 2022.

MATERIALS AND METHODS

An institutional-based cross-sectional study was employed. We used 610 women who gave birth at North Shoa Zone Hospitals, Amhara region, Ethiopia. The study was conducted from June 8 to August 8, 2022. Recruitment for the study was made using a multistage sampling procedure. Fifty percent of the study hospitals were randomly selected, and proportional allocation was done. Participants were selected from the sampling frame, labour and delivery register book, using a systematic random sampling approach. The first person was selected at random, while the remaining individuals were selected at every two "K" intervals across all hospitals. An interview-administered structured questionnaire and chart review checklist were used to gather the data that were entered into Epi-Data Version 4.6 and exported to SPSS. Logistics regression was employed, and a p-value <0.05 was considered statistically significant.

RESULT

The magnitude of meconium-stained amniotic fluid was 30.3%. Women with a normal hematocrit level were 83% less likely to develop meconium-stained amniotic fluid. Women whose mid-upper arm circumference value was less than 22.9cm (AOR = 1.9; 95% CI: 1.18-3.20), obstructed labour (AOR = 3.6; 95% CI: 1.48-8.83), prolonged labour ≥ 15 hr (AOR = 7.5; 95% CI: 7.68-13.3), premature rapture of membrane (AOR = 1.7; 95% CI: 3.22-7.40), foetal tachycardia (AOR = 6.2; 95% CI: 2.41-16.3), and Bradycardia (AOR = 3.1; 95% CI: 1.93-5.28) showed a significant association with meconium-stained amniotic fluid.

CONCLUSION

The present study revealed that the magnitude of meconium-stained amniotic fluid in North Shoa Zone is nearly one-third. A normal hematocrit level is a preventive factor for meconium-stained amniotic fluid, and a MUAC value <22.9 cm, obstructed and prolonged labour, PROM, bradycardia, and tachycardia are factors associated with meconium-stained amniotic fluid.

Development and validation of a predictive model for early diagnosis of neonatal acute respiratory distress syndrome based on the Montreux definition

Objective

Based on the Montreux definition, we aim to develop and validate a predictive model for the early diagnosis of neonatal acute respiratory distress syndrome (ARDS).

Methods

A retrospective analysis of clinical data on 198 neonates with respiratory distress from January 2018 to January 2022 was conducted. Neonates meeting Montreux definition were classified as ARDS group (n = 79), while the rest were non-ARDS group (n = 119). Univariate analysis identified indicators for neonatal ARDS, followed by logistic regression to construct a predictive model for early diagnosis. The ability of predictors and models to predict neonatal ARDS was evaluated using area under the curve (AUC), and model performance was estimated through bootstrap resampling.

Results

Maternal prenatal fever, abnormal fetal heart beat, meconium-stained amniotic fluid (MSAF), white blood cell (WBC), absolute neutrophil count (ANC), neutrophil percentage (NE%), platelet count (PLT), C-reactive protein (CRP), procalcitonin (PCT), creatine kinase (CK), activated partial thromboplastin time (APTT), serum calcium (Ca) and sodium (Na)exhibited significant differences between the ARDS group and the non-ARDS group (P < 0.05). MSAF (OR=5.037; 95% CI: 1.523-16.657; P < 0.05), ANC (OR = 1.324; 95% CI: 1.172-1.495; P < 0.05), PLT (OR = 0.979; 95% CI: 0.971-0.986; P < 0.05), Ca (OR = 0.020; 95% CI: 0.004-0.088; P < 0.05) emerged as independent risk factors for the development of ARDS. The respective AUC values for MSAF, ANC, PLT, Ca, and the combined prediction models were 0.606, 0.691, 0.808, 0.761 and 0.931. Internal validation showed that the C-index for the model was 0.931.

Conclusions

Early application of the model combining MSAF, ANC, PLT and Ca may have a good predictive effect on the early diagnosis of neonatal ARDS.

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.

The incidence and determinants of the meconium-aspiration syndrome among mothers with meconium-stained amniotic fluid after emergency cesarean section: A prospective cross-sectional study in a specialized hospital, south Ethiopia

Background

Meconium aspiration syndrome is respiratory distress diagnosed in neonates delivered with meconium-stained amniotic fluid that is unexplained by other pathologies. It has severe neonatal respiratory complications and a significant impact on the prevalence of neonatal mortality.

Objective

To identify the incidence and determinants associated with meconium aspiration syndrome among mothers with meconium-stained amniotic fluid after emergency cesarean section in Wolkite University specialized hospitals in Ethiopia from September 1, 2021, to August 30, 2022.

Method

An institution-based cross-sectional study was done prospectively through meticulous chart review and interviews with 275 mothers with meconium-stained amniotic fluid who gave birth with an emergency cesarean section. Data were entered using EpiData 7 and analyzed with SPSS 26. The association between independent variables and the meconium-aspiration syndrome was estimated using an odds ratio with 95% confidence intervals. The statistical significance of the association was declared at a p-value of 0.05.

Result

The prevalence of the meconium-aspiration syndrome is 28.7%. The factors associated are: latent phase (AOR: 2.580; 95% CI: 1.126, 5.913), low 1st minute APGAR score (AOR: 2.43; 95% CI: 0.892, 6.625), and thick meconium (AOR: 31.018; 95% CI: 9.982, 96.390). The neonatal death rate associated with meconium aspiration syndrome is 1.8%, and thick meconium contributed to 65% of admissions to the neonatal intensive care unit and all deaths.

Conclusion

The incidence of meconium aspiration syndrome is high, and thick meconium, meconium at early labor, and low APGAR scores all contributed to this. Thick meconium has a substantial effect on neonatal mortality and morbidity. Therefore, an improvement in the quality of obstetric and neonatal care through early intervention in the case of thick meconium and meconium in the early phase of labor is recommended.

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.

Does meconium contaminated amniotic fluid affect intestinal wall thickness and functional outcome in patients with anterior abdominal wall defects?

BACKGROUND

Gastroschisis (GS) and omphalocele (OC) are congenital abdominal wall defects, the main difference between is the direct exposure of intestinal loops in amniotic fluid in children with a GS. This leads to a reduced primary closure rate and a higher number of intraoperative abnormalities and post-operative complications.

AIMS AND OBJECTIVES

We analysed abdominal wall defect patients over an 11-year period, aiming to assess the influence of meconium-contaminated amniotic fluid. This study has different objectives to show the consequence of functional outcome of abdominal wall defects (AWD) children in reliance to colour of amniotic fluid, to assess the effect of reduced bowel exposure time to meconium contaminated amniotic fluid on edematous inflammatory thickening of the bowel loops, to show an positively influence in the number of primary AWD closures, to demonstrate a reduced incidence of post-natal complications and to verify a better outcome of OC children because of failing exposure to amniotic fluid.

METHODS

A retrospective, observational case-control design was used to compare GS (n = 36) and OC (n = 18) children. Physical data, colour of amniotic fluid, pre- and perinatal problems, operative complications and surgical technique, post-operative complications, duration of intensive care unit (ICU) stay, mechanical ventilation, parenteral nutrition, commencement of oral feeding and total hospital stay were collected. Data were analysed with descriptive methods, t-test and non-parametric tests such as Wilcoxon and Kruskal-Wallis were performed in addition to the analysis of variance, including post hoc testing accepting a confidence interval of 95% (P < 0.05) by using IBM SPSS software, version 23 (IBM, Illinois, USA).

RESULTS

Rate of meconium-contaminated amniotic fluid is significantly higher in GS compared to OC (P < 0.001), delivery problems such as congenital infections are also significantly higher (P < 0.001), this yields in significantly more bowel loops anomalies and problems during surgery (P < 0.036) but had no significant influence on primary abdominal wall closures rate (P = 0.523). The post-surgical outcome of OC was significantly better as compared to GS. Within the GS, those with swollen intestines had significantly longer ICU stays (P = 0.045) due to extended mechanical ventilation (P = 0.007), parenteral nutrition (P = 0.011) and delayed initiation of oral feeding (P < 0.001. Same results were found for the duration of ICU stay (P = 0.008), mechanical ventilation (P = 0.006), parenteral nutrition (P = 0.011) and delayed initiation of oral feeding (P < 0.001) in secondary closures as compared to primary abdominal wall closures in the GS group.

CONCLUSIONS

Worsen functional short-term outcome of GS children was directly addicted to meconium contamination of amniotic fluid due to swollen intestines and because of this more post-surgical problem including significantly extended hospital stays were observed.

Prevalence and Factors Associated with Meconium-Stained Amniotic Fluid in a Tertiary Hospital, Northwest Ethiopia: A Cross-Sectional Study

Background. Fetal bowel could pass meconium, a green viscous fluid, before or during labour and most intrauterine passage of meconium is associated with several fetomaternal factors that lead to increased risk of perinatal morbidity and mortality. Given that there is a paucity of data, this study was conducted to assess the proportion and associated factors of meconium-stained amniotic fluid (MSAF) in women who came for labour and delivery service in a tertiary hospital. Methods. A cross-sectional study was conducted from 1 June to 31 August 2018 among 606 labouring mothers at Felege Hiwot Referral Hospital, northwest Ethiopia. Study participants were selected using a systematic random sampling technique. Data were collected using an interviewer-administered pretested questionnaire and data checklist. Factors associated with MSAF were explored using multivariable logistic regression analysis. Results. MSAF occurred in 24.6% (149/606) of pregnancies. Nonreassuring fetal heart rate patterns (Adjusted Odds Ratio [AOR]: 21.9, 95% Confidence interval [95% CI]: 10.96–43.83), postterm pregnancy (AOR: 4.54, 95% CI: 2.24–9.20), duration of labour more than 15 hours (AOR: 2.83, 95% CI: 1.76–4.53), pregnancy-induced hypertension (AOR: 2.43, 95% CI: 1.45–4.05), oligohydramnios (AOR: 2.53, 95% CI: 1.25–5.12), interpregnancy interval less than 2 years (AOR: 2.24, 95% CI: 1.12–4.51), and monthly family income less than 5000 Ethiopian Birr (185 USD) (AOR: 2.03, 95% CI: 1.18–3.51) were significantly associated with MSAF. Conclusions. In this study, the proportion of MSAF was at 24.6% which was higher than a previous report in Ethiopia. Nonreassuring fetal heart rate pattern, postterm pregnancy, duration of labour more than 15 hours, pregnancy-induced hypertension, oligohydramnios, interpregnancy interval less than 2 years, and monthly family income less than 5000 Ethiopian Birr were factors associated with an increased risk for MSAF. Therefore, interventions aimed at detecting MSAF early should consider these factors.

Neonatal Respiratory Distress Secondary to Meconium Aspiration Syndrome

Infants born through meconium-stained amniotic fluid (MSAF) are 100 times more likely than infants born through clear amniotic fluid to develop respiratory distress in the neonatal period. Meconium aspiration syndrome (MAS) is a common cause of respiratory distress in term and post-mature neonates. MAS is defined as respiratory distress accompanied by a supplemental oxygen requirement in an infant born with MSAF, in the absence of any other identified etiology to explain the symptoms. Therapy for MAS is supportive, and should be tailored to each infant’s specific pathophysiology. In cases of MAS with severe persistent pulmonary hypertension of the newborn (PPHN), patients may remain hypoxic despite aggressive ventilation, and in these cases surfactant, inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation (ECMO) can be life-saving. Long-term prognosis for MAS is more related to severity of initial hypoxemia and possible neurological insult than to the pulmonary pathology.

Fetal scalp blood sampling: Do pH and lactates provide the same information?

OBJECTIVE

Assess the discordance between scalp pH and lactates performed from the same sample during labor.

METHOD

This single-center retrospective study included all women with a singleton fetus who had at least one fetal blood sample taken during labor. Some of them had up to seven samples. Scalp pH was the reference parameter for obstetric decision-making. The correlation between the pH and lactates was studied using Pearson coefficient. By categorizing the values as normal, pre-acidosis and acidosis, we were able to estimate agreement with Cohen's kappa coefficient. The frequency of discordance in the categorization and the factors related to it were studied with univariate and multivariable analyses. Cases of severe acidosis at birth (cord pH < 7.00) and cases with acidosis scalp lactates but normal scalp pH were analyzed.

RESULTS

We analyzed 480 samples from 268 fetuses among the 2644 deliveries during the study periode. Fetal blood sampling represented 10 % of deliveries. The scalp pH and lactates results were strongly correlated (r=-0.83), but their agreement was only fair (K = 0.36). In 29.4 % of cases, pH and lactates were discordant. Factors related to discordance were meconium-stained fluid, sampling at full dilation and multiple sampling. Six infants (2.2 %) had severe acidosis at birth. Cases' analyses did not allow to conclude severe acidosis could have been avoided using scalp lactates for obstetric decision-making.

CONCLUSION

For more than a quarter of the samples, results were discordant between scalp pH and lactates, especially when cervix was full dilated and when the amniotic fluid was meconium-stained. A randomized controlled trial comparing the relevance of each parameter according to the obstetrical situation would be necessary.

Meconium aspiration syndrome in infants of HIV-positive women: a case-control study

OBJECTIVE

Our aim was to determine whether maternal HIV infection in the current era is associated with an increased incidence of meconium aspiration syndrome (MAS) in their infants.

METHODS

Infants born to 149 HIV-positive women at our hospital over a 5-year period were compared with infants born to HIV-negative women in a retrospective case-control study. Charts of all 298 patients included in the study were reviewed for maternal and infant demographics, HIV treatment, vertical transmission and untoward events at delivery or during the hospital course.

RESULTS

When compared with HIV-negative women, a greater proportion of HIV-positive women had meconium-stained amniotic fluid (MSAF), 33% vs. 13%, P<0.001; and thick MSAF, 17% vs. 5%, P<0.001, respectively. Seven of 298 infants were admitted to the neonatal intensive care unit for MAS; all seven were born to HIV-positive women (P=0.015). Although in utero exposure to illicit drugs is a reported risk factor for meconium staining of the amniotic fluid and such drug exposure was more common among our HIV-positive sample, controlling for this and other possible covariates did not greatly reduce the association of HIV status with meconium-related complications of delivery.

CONCLUSIONS

Infants born to HIV-positive women had significantly more MSAF and MAS than infants born to non-infected women. It is unclear whether this association results from maternal HIV infection itself or from anti-retroviral therapy. Maternal and infant care providers should be prepared for this complication when attending to the deliveries of HIV-positive women.

Interpreting category II fetal heart rate tracings: does meconium matter?

OBJECTIVE

Category II fetal heart rate (FHR) tracings are considered indeterminate; thus, improved risk stratification of category II FHR tracings is needed. We estimated whether the presence of meconium increased the risk of adverse neonatal outcomes.

STUDY DESIGN

This study was conducted within a prospective cohort of 5000 women with singleton pregnancies who were admitted in labor at term. Pregnancies with category II FHR in the 60 minutes before delivery were included. FHR data were extracted by trained nurses who were blinded to clinical outcome. The exposure was the presence of meconium. The primary outcome was a composite neonatal morbidity defined as ≥1 of the following: neonatal death, neurologic morbidity, respiratory morbidity, hypotension that required treatment, and sepsis. Secondary outcomes were nursery admission, cord pH, 5-minute Apgar score, and components of the composite. Logistic regression was used to adjust for confounders.

RESULTS

Of the 3257 women with category II FHR tracings, 693 women (21.3%) had meconium, and 2564 women (78.7%) did not. Meconium was associated with higher risk of the composite morbidity (adjusted odds ratio, 2.49; 95% confidence interval, 1.78-3.48) and increased risks of the secondary outcomes. The associations remained significant when infants with meconium aspiration syndrome were excluded. Thick meconium was associated significantly with the composite morbidity.

CONCLUSION

The presence of meconium is associated with an increased risk of neonatal morbidity in women with category II FHR pattern. This clinical factor may assist clinicians in managing category II FHR patterns in labor.

The aetiology of meconium-stained amniotic fluid: pathologic hypoxia or physiologic foetal ripening? (Review)

INTRODUCTION

Despite the many efforts to study the (patho)physiology of meconium release before delivery, it still remains an indistinct subject. Some studies have reported a relationship between hypoxia and MSAF, whilst others have not. The most common association found however, is between MSAF and the term of gestation.

METHODS

MEDLINE, EMBASE and the Cochrane library were electronically searched. Papers about the (patho)physiology of meconium-stained amniotic fluid in English were included. Papers about management strategies were excluded (see elsewhere this issue).

RESULTS

Different theories have been proposed including acute or chronic hypoxia, physiologic foetal ripening and peripartum infection.

CONCLUSION

We suggest that meconium-stained amniotic fluid should be regarded as a symptom rather than a syndrome becoming more prevalent with increasing term and which might be associated with higher levels of infection or asphyxia.

Hepcidin and erythropoietin measurements in the cord blood of neonates with meconium-stained amniotic fluid

AIM

To compare hepcidin and erythropoietin levels in the cord blood of neonates with meconium-stained amniotic fluid (MSAF) to levels obtained from age-, body mass index- and gravidity-matched neonates with clear amniotic fluid.

METHODS

A cross-sectional controlled study was conducted in secondary and tertiary care centers. Cord blood samples of 40 neonates following term gestations (≥37 weeks' gestation) with MSAF and 40 maternal age-, body mass index- and gravidity-matched controls with clear amniotic fluid were analyzed in this study. Demographic data, delivery outcomes and laboratory evaluations were recorded.

RESULTS

Cord blood pH levels were lower in fetuses with MSAF when compared to those with clear amniotic fluid (P=0.0001). Fetuses with MSAF had higher cord blood erythropoietin levels in comparison to those with clear amniotic fluid (P=0.0001). Delivery outcomes and hepcidin measurements were similar in both groups.

CONCLUSIONS

We demonstrated a significant relationship between erythropoietin levels and meconium passage, but failed to show the existence of a relationship between hepcidin levels and meconium passage.

The frequency of meconium-stained amniotic fluid increases as a function of the duration of labor

OBJECTIVE

The purpose of this study was to determine whether there is a relationship between the frequency of meconium-stained amniotic fluid (MSAF) and the duration of labor in term singleton gestation.

METHODS

The clinical characteristics of women who delivered term singleton live newborns between 2001 and 2006 were examined. The cases involving neonates with major congenital anomalies were excluded.

RESULTS

(1) The frequency of MSAF in term pregnancies was 18.4% (806/4376); (2) MSAF was found in only 2.8% (28/1008) of women who delivered by elective cesarean, but in 23.1% (778/3368) of women who delivered after the onset of labor (p < 0.001); (3) The longer the duration of labor (first stage, second stage, or total), the higher the frequency of MSAF (p < 0.001 for each); this remained significant after adjusting for other confounding variables such as parity, duration of rupture of membranes, gestational age at delivery, and mode of delivery (p < 0.001 for each).

CONCLUSION

MSAF was found in only 2.8% (28/1008) of women who delivered before the onset of labor, but in 23.1% (778/3368) of women who delivered after the onset of labor. The longer the duration of labor, the higher the risk of MSAF in term singleton gestation.

Localization and gestation-dependent pattern of corticotrophin-releasing factor receptor subtypes in ovine fetal distal colon

Meconium passage is frequently observed in association with feto-maternal stress factors such as hypoxia and infection, but the triggering mechanism is unknown. We hypothesize that differential regulation of corticotrophin-releasing factor (CRF) receptors during gestation play an important role in determining the susceptibilities of the fetus to stress-induced in utero meconium passage at term. We examined the innervation patterns of CRF-receptor type 1 (CRF-R1), a stimulator of gastrointestinal motility and CRF-receptor type II (CRF-R2), an inhibitor of gastrointestinal motility in ovine fetal distal colonic segments from very preterm to term gestation. Both CRF-R1 and CRF-R2 receptors were present in muscularis mucosa as well as in longitudinal and circular smooth muscle layers in fetal distal colonic segments at all gestational ages. Quantitative image analysis indicated a 42% increase in CRF-R1 receptor immunoreactivity in muscularis mucosa and a 30% in longitudinal smooth muscle layers from very preterm to term. In contrast, CRF-R2 receptor immunoreactivity in muscularis mucosa as well as in longitudinal and circular smooth muscle layers decreased by 38%, 55% and 51%, respectively, at term. The percentage of enteric ganglia and the number of enteric neurons expressing CRF-R1 receptors were high at term. Western blot analysis identified 235 and 50 kDa molecular species of CRF-R1 receptors and 37 and 28 kDa molecular species of CRF-R2 receptors. In summary, we speculate that downregulation of CRF-R2 receptor abundance with concurrent increases in CRF-R1 receptor levels in myenteric-smooth muscle unit with advancing gestation sensitizes the colonic motility responses to stressors.

Mechanism(s) of in utero meconium passage

To use sheep and rat models and demonstrate that stressors activate fetal glucocorticoid (GC) system, corticotrophin-releasing factor (CRF) system and cholinergic neurotransmitter system (ChNS) leading to propulsive colonic motility and in utero meconium passage. Immunohistochemical studies (IHS) were performed to localize GC-Receptors, CRF-receptors and key molecules of ChNS in sheep fetal distal colon. CRF expression in placenta and enteric endocrine cells in fetal rat system were examined and the effects of acute hypoxia on in utero meconium passage was tested. IHS confirmed localization and gestation dependent changes in GC-Rs, CRF-Rs and cholinergic markers in sheep fetal colon. Rat placenta and enteric endocrine cells express CRF and gastrointestinal tract express CRF-Rs. Hypoxia is a potent inducer of meconium passage in term fetal rats. Stress is a risk factor for in utero meconium passage and laboratory animal models can be used to develop pharmacotherapy to prevent stress-induced in utero meconium passage.