Meconium-stained amniotic fluid – risk factors and immediate perinatal outcomes among SGA infants

Determinants of meconium-stained amniotic fluid among women delivered at southwestern referral hospitals, Southwest Ethiopia: a multi-center case-control study

BACKGROUND

Meconium-stained amniotic fluid (MSAF) is a condition in which meconium is present in the uterus during ante-natal and complicates 10-15% of all live births. Scanty information is known about the determinants of meconium-stained amniotic fluid. Hence, this study aimed to identify determinants of meconium-stained amniotic fluid among women delivered at southwestern referral hospitals in southwest Ethiopia, in 2024.

METHODS

An institutional-based case-control study was employed from January 1, 2024, to June 30, 2024. The study was conducted in four southwestern referral hospitals in southwest Ethiopia. The final sample size includes 321(107 cases and 214 controls). The sample size was proportionally allocated for cases and controls for each referral hospital. Simple random sampling was used to select patient charts and data was collected from the chart using questions/tools developed after reviewing relevant literature. Data were entered using Epi-data version 3.1 and analyzed using SPSS version 25. Data was analyzed using binary logistic regression. All independent variables with P- the value of < 0.25 in univariable analysis were considered for multivariable logistic regression. Determinant factors of meconium-stained amniotic fluid were identified at a 95% confidence interval with a p-value < 0.05 was utilized to declare statistical significance.

RESULTS

A total of 107 cases and 214 controls were included in this study. The finding from this study stated that induction of labor [AOR = 2.37, 95% CI = 1.28-8.89], obstructed labor [AOR = 2.62, 95%CI = 1.1-6.79], duration of labor greater than 24 h [AOR = 2.8, 95% CI = 1.55-15.44], and premature rupture of the membrane [AOR = 2.98, 95%CI = 1.1-8.23] were found to be significantly associated with meconium-stained amniotic fluid.

CONCLUSION

Conclusively, a mother with induced or obstructed labor, labor duration greater than 24 h, and premature rupture of membrane need special attention during delivery care to reduce potential risk factors to feto-maternal outcomes related to meconium-stained amniotic fluid.

Determinants of meconium-stained amniotic fluid among laboring mother in Ethiopia, systematic review and meta-analysis

Background

Meconium-stained amniotic fluid (MSAF) occurs during childbirth when the amniotic fluid carries traces of meconium, the initial stool passed by a newborn. Often signaling fetal distress, MSAF is linked to heightened risks for both the mother and the newborn. In Ethiopia, there is insufficient attention given to this condition. Despite varied study results indicating a considerable range in MSAF occurrences, there is an absence of a comprehensive national overview. Therefore, this systematic review and meta-analysis aim to evaluate the aggregated prevalence of meconium-stained amniotic fluid among laboring mothers and its influencing factors in Ethiopia, providing a consolidated understanding for healthcare strategies and policies.

Method

Following PRISMA guidelines, a systematic review and meta-analysis were executed. Extensive literature searches were conducted on PubMed, Google Scholar, and African Online Journal databases. The pooled prevalence was estimated using a weighted inverse variance random effect model. Heterogeneity among studies was evaluated through Cochrane Q-test and I 2 statistics. To assess publication bias, a funnel plot and Egger's test were performed. The identification of factors associated with meconium-stained amniotic fluid among laboring mothers in Ethiopia was conducted using Stata v 18 software.

Result

In total, 63 articles were initially identified, and ultimately, four articles were deemed suitable for inclusion in this review. The combined prevalence of meconium-stained amniotic fluid among laboring mothers in Ethiopia was determined to be 20% (95% CI: 14%-25%). Upon conducting subgroup analysis, it was revealed that the prevalence of meconium-stained amniotic fluid was highest in the Oromia region and lowest in Addis Ababa. Notably, pregnancies complicated by pregnancy-induced hypertension disorder showed a significant association with the presence of meconium-stained amniotic fluid, with an odds ratio of 6.21 (95% CI: 4.04-8.38).

Conclusion

In conclusion, this review emphasizes the common occurrence of meconium-stained amniotic fluid (MSAF). Notably, it identifies a significant association between pregnancy complicated by hypertension and the presence of MSAF. This underscores the need for targeted interventions to reduce MSAF incidence and mitigate associated adverse outcomes in the Ethiopian.

Systematic Review Registration

http://www.library.ucsf.edu/, (CRD42023491725).

Correlation between total deceleration area and fetal cord blood pH in neonates complicated with meconium-stained amniotic fluid at term

OBJECTIVE

To assess the correlation between total area under the Curve (AUC) of decelerations and accelerations and neonatal acidemia in pregnancies complicated with meconium-stained amniotic fluid (MSAF).

METHODS

A retrospective cohort study was conducted among women who delivered with a diagnosis of MSAF. Electronic fetal monitoring (EFM) patterns 120 min before delivery were interpreted by a researcher blinded to fetal outcomes. The primary outcome was fetal acidemia, defined as umbilical artery pH below 7.10. The correlation was tested using the Spearman correlation coefficient.

RESULTS

A total of 102 women were included; 24 delivered infants with cord blood pH < 7.20, and only five delivered infants with cord blood pH < 7.10. A significant correlation was demonstrated between total AUC of decelerations and accelerations and cord blood pH (P = 0.02). A sub-analysis according to gestational age at delivery (up to and beyond 40 weeks) was conducted. A significant correlation was demonstrated (P = 0.02) only in the term group(n = 37).

CONCLUSION

A correlation was demonstrated between total AUC of decelerations and accelerations and cord blood pH in neonates with MSAF. This correlation was significant for neonates delivered before 40 weeks of gestation, but not for those delivered after 40 weeks of gestation.

Exposure to Meconium-Stained Amniotic Fluid and Long-Term Neurological-Related Hospitalizations throughout Childhood

OBJECTIVE

This study aimed to investigate the possible impact of meconium-stained amniotic fluid (MSAF) on the occurrence of neurological-related hospitalizations throughout childhood and adolescence.

STUDY DESIGN

In this population-based cohort analysis, all singleton deliveries occurring between 1991 and 2014 at the Soroka University Medical center were included and the long-term neurological-related hospitalizations were compared between children with and without MSAF during their delivery. A Kaplan-Meier survival analysis was constructed for the evaluation of cumulative hospitalization rate due to neurological morbidity over the 18 years of follow-up, and a Cox proportional hazards model was used to study the independent association between MSAF and childhood neurological morbidity while controlling for potential confounders.

RESULTS

During the study period, 243,725 deliveries met the inclusion criteria; 35,897 of the cohort (15%) constituted the exposed group (MSAF), while the rest of the cohort (n = 207,828) constituted the unexposed group (no MSAF). A total of 7,543 hospitalizations due to neurological-related morbidity were documented with a rate of 3.2% (1,152) in children exposed to MSAF as compared with 3.1% (6,391) in the unexposed group (OR 1.1, 95% confidence interval 0.9-1.1, p = 0.149). The survival curve showed a comparable cumulative hospitalization rate in the MSAF-exposed group compared with the unexposed group (log rank p = 0.349). The Cox analysis, controlled for gestational diabetes and hypertension, gestational and maternal ages, demonstrated MSAF exposure not to be an independent risk factor for neurological-related hospitalizations during childhood (adjusted hazard ratio = 1.03, 0.96-1.09).

CONCLUSION

Fetal exposure to MSAF, at any gestational age, does not appear to be an independent risk factor for later neurological-related hospitalizations throughout childhood and adolescence.

KEY POINTS

· MSAF is associated with several short-term complications such as low Apgar scores.. · The long-term implications of MSAF exposure are yet to be clearly defined.. · Fetal exposure to MSAF is not a risk factor for neurological morbidity throughout childhood..

Approach to the Connection between Meconium Consistency and Adverse Neonatal Outcomes: A Retrospective Clinical Review and Prospective In Vitro Study

Whether meconium-stained amniotic fluid (MSAF) serves as an indicator of fetal distress is under debate; however, the presence of MSAF concerns both obstetricians and pediatricians because meconium aspiration is a major contributor to neonatal morbidity and mortality, even with appropriate treatment. The present study suggested that thick meconium in infants might be associated with poor outcomes compared with thin meconium based on chart reviews. In addition, cell survival assays following the incubation of various meconium concentrations with monolayers of human epithelial and embryonic lung fibroblast cell lines were consistent with the results obtained from chart reviews. Exposure to meconium resulted in the significant release of nitrite from A549 and HEL299 cells. Medicinal agents, including dexamethasone, L-Nω-nitro-arginine methylester (L-NAME), and NS-398 significantly reduced the meconium-induced release of nitrite. These results support the hypothesis that thick meconium is a risk factor for neonates who require resuscitation, and inflammation appears to serve as the primary mechanism for meconium-associated lung injury. A better understanding of the relationship between nitrite and inflammation could result in the development of promising treatments for meconium aspiration syndrome (MAS).

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.

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.

The risk of meconium aspiration syndrome (MAS) increases with gestational age at term

Objective: To examine the risk of meconium aspiration syndrome (MAS) by the week of gestational age in pregnancies with meconium-stained amniotic fluid (MSAF).Methods: This is a retrospective cohort study derived from term pregnancies at a single tertiary institution over an 18-year period. Outcomes analyzed included MAS, acidemia, and Apgar scores. Univariate analysis was performed using chi-square and multivariable logistic regression was used to adjust for potential confounders.Results: A total of 34,303 deliveries ≥37 weeks were included; 23.7% were complicated by MSAF. Of the total study cohort, 272 (0.7%) neonates were diagnosed with MAS; this represented 3% of all deliveries complicated by MSAF. In the presence of MSAF, the risk of MAS increased with gestational age, from 1.3% at 38 weeks to 4.8% at 42 weeks (p < .001). Similarly, the risk of acidemia increased from 3.0% at 38 weeks to 7.0% at 42 weeks (p < .001). These findings were also demonstrated in patients with MAS in the absence of MSAF. The risk for both MAS and acidemia in the presence of MSAF persisted after controlling for potential confounders (aOR 1.31 [95% CI 1.18-1.46] and 1.20 [95% CI 1.05-1.37], respectively).Conclusion: In women with MSAF, as gestational age increases, the risk of meconium aspiration syndrome also increases. Other factors with late-term and post-term pregnancy besides the presence of meconium may contribute to the evolution of MAS.

Intrauterine Growth Restriction: Postnatal Monitoring and Outcomes

Intrauterine growth restriction (IUGR) is an important cause of fetal, perinatal and neonatal morbidity and mortality. IUGR occurs because of multiple reasons. Neonates with IUGR experience acute problems in the perinatal and early neonatal period that can be life-threatening. The unfavorable uterine environment causing growth restriction results in programming that predisposes IUGR infants to long-term health issues such as poor physical growth, metabolic syndrome, cardiovascular disease, neurodevelopmental impairment and endocrine abnormalities, warranting careful monitoring. It is imperative to strike the balance between achieving optimal catch-up to promote normal development, while preventing the onset of cardiovascular and metabolic disorders in the long-term.

New Evidence to Support Antibiotic Prophylaxis in Meconium-Stained Amniotic Fluid in Low-Risk Women in Labor a Prospective Cohort Study

Purpose of study

To assess the maternal and perinatal complications associated with meconium-stained amniotic fluid (MSAF) in low-risk women in labor.

Methods

This prospective cohort study was conducted at CMC Hospital, Vellore, India. Two hundred low-risk women who had artificial or spontaneous rupture of membranes after admission with MSAF were included in the study. Two hundred similar women with clear liquor were taken as controls. The primary outcomes considered were the incidence of chorioamnionitis and endomyometritis in the mothers. The secondary outcomes included postpartum hemorrhage and retained placenta in the mothers and respiratory distress, meconium aspiration, sepsis, and NICU admission in the newborn. Statistical analysis was done using Fischer exact test. Odds ratio, 95% confidence interval, and P value were estimated.

Results

Compared to controls, those with MSAF had significantly higher rates of chorioamnionitis (2 vs. 8%, P = 0.006) and endomyometritis (3 vs. 9.5% P = 0.007). Among the secondary end points, only neonatal respiratory distress (8.5 vs. 1.5%; P = 0.001) and meconium aspiration (4 vs. 0%; P = 0.007) were found to be significantly increased in the meconium group.

Conclusion

Statistically significant increased incidence of chorioamnionitis and endomyometritis in women with MSAF in labor established in our study strongly supports the use of prophylactic antibiotics in these women to prevent immediate and long-term consequences.

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.

Should fetal scalp blood sampling be performed in the case of meconium-stained amniotic fluid?

OBJECTIVE

To investigate the effect of using fetal scalp blood sampling on the risk of neonatal respiratory distress syndrome (NRDS) with meconium-stained amniotic fluid (MSAF).

METHODS

Prospective data collection with regard to MSAF during labor for low-risk term cephalic singleton live birth from 2012 to 2014. Maternal, obstetric and neonatal data were compared according to the occurrence of respiratory distress syndrome (RDS group) or not (no RDS group).

RESULTS

Of 515 newborns born through MSAF, 46 experienced RDS and from them 10 experienced meconium aspiration syndrome. No difference was observed according to maternal characteristic, abnormal fetal heart rate tracing pattern irrespective of its category and cesarean rate. Apgar at one minute was lower in the group RDS (7.6 versus 8.5, p < 0.05). The mean umbilical artery pH values did not differ between the two groups. Significant difference between newborns with and without RDS in terms of fetal scalp lactate sampling during the labor (71.1% versus 55.1%, p < 0.05), and neonatal care unit (NCU) admissions (22.8% versus 10.8%, p < 0.05). Secondary rather than primary meconium was associated with RDS when performing fetal scalp blood assessment (p < 0.05). A significant correlation between RDS, fetal scalp blood assessment and MSAF diagnosed during the first stage of labor (after spontaneous rupture of membranes or at amniotomy) was found.

CONCLUSION

In case of MSAF, fetal scalp blood sampling did not reduce the risk of RDS.