Fetal tachycardia and meconium staining: A sign of fetal infection

A retrospective study was carried out on 72 liveborn babies in whom perinatal infection was suspected. Twenty-nine of the 72 neonates were effectively infected. Analysis of intrapartum FHR recordings showed that tachycardia (base line FHR above 160 beats/min) during labor, occurred more often among infected babies (P < 0.001). When fetal tachycardia is associated with meconium stained amniotic fluid (MSAF), the relative risk of fetal infection is 51 times as great as in babies without MSAF. Fetal tachycardia is not related to maternal fever nor to prematurity. It is not a sign of limited placental or amniotic fluid infection, but implies infection of the fetus itself. Since most infected babies displayed infectious diarrhea immediately at birth, it is suggested that MSAF may eventually be due to antenatal intestinal infection and intrauterine emission of infected stools. Although great caution is advocated for the management of labor in the presence of fetal tachycardia, MSAF should not be always regarded as a sign of acute fetal distress when antenatal infection of the fetus is suspected.     

Meconium stained amniotic fluid in very low risk pregnancies at term gestation

Objective: To determine the prevalence and clinical significance of meconium stained amniotic fluid (MSAF) in a low risk population at term gestation and to investigate whether MSAF is a predictor for intrapartum and neonatal morbidity. Methods: A very low risk population including 37 085 consecutive deliveries at term composed the study population. A cross-sectional study was conducted and two groups of patients were identified according to the presence (n=6164) or absence (n=30 921) of meconium in the amniotic fluid at delivery and the outcomes of the two groups compared. Results: The prevalence of MSAF was 16.6%. The incidence of cesarean section (5.6% vs 2.3% P<0.01), instrumental deliveries (3.2% vs 1.8% P<0.01), fetal distress (6.5% vs. 2.1% P<0.01), clinical chorioamnionitis (0.2% vs. 0.1% P<0.01), post-partum infection (0.5% vs. 0.2% P<0.01), 1-minute Apgar score <3 (1.9% vs. 1.1% P<0.01), small for gestational age (7.4% vs. 6.4% P<0.01). was significantly higher in the MSAF compared with the clear amniotic fluid group. Intrapartum and neonatal mortality in this low risk population was significantly higher in the MSAF group ( ) compared with women with clear AF ( ). Conclusions: MSAF in a low risk population at term gestation is a predictor for adverse perinatal outcome and peripartum complications.     

Risk factors for meconium aspiration in meconium stained amniotic fluid.

Meconium aspiration syndrome (MAS) is a life-threatening respiratory disease in infants born through meconium stained amniotic fluid (MSAF). The purpose of this study was to determine risk factors for MAS in the newborns of mothers who had meconium stained amniotic fluid in labour. A retrospective study of all full-term pregnancies with MSAF from May 2003 to October 2004 was designed at a teaching hospital. Development of MAS was the primary outcome. Maternal details, mode of delivery and neonatal details (Apgar score, reassuring or non-reassuring fetal heart rate tracing and birth weight) were evaluated. During the study period, there were 2,603 deliveries of whom 302 (11.6%) had MSAF. MAS developed in 64 of these infants (21.1%). Compared with healthy neonates with MSAF, those with MAS had higher rate of non-reassuring fetal heart rate (FHR) tracing, thick meconium and Apgar score < or =5 at 5 min. The neonatal birth weight was lower in the MAS group, maternal age, parity, gestational age and mode of delivery were not significantly different in the two group. We found the severity of meconium, low Apgar score at 5 min and non-reassuring FHR tracing was associated with MAS in MSAF pregnancies.     

Incidence of chorioamnionitis in patients with meconium-stained amniotic fluid

Objective: The goal of this study was to determine if meconium staining of the amniotic fluid (MSAF) is a marker for chorioamnionitis.Methods: In a retrospective, case-control investigation, we studied 100 patients with MSAF. Each patient was matched with a control who delivered during the same period but did not have MSAF. Subjects and controls were matched for age, parity, gestational age, mode of delivery, duration of rupture of membranes (ROM), length of internal monitoring, and number of examinations before and after ROM. The incidence of chorioamnionitis in controls and study patients was compared. The diagnosis of chorioamnionitis was based on clinical examination.Results: Thirteen of the 200 patients [6.5%, 95% confidence interval (CI), 2.5-10.5%] developed chorioamnionitis. Of the 100 women with MSAF, 10 (10%, 95% CI, 4-16) were infected compared with only 3 controls (3%, 95% CI, 0-6, P = 0.04). The odds ratio (OR) for this comparison was 3.3, and the 95% CI was 1.02-10.63.Conclusions: MSAF is associated with an increased frequency of chorioamnionitis. Several factors could explain this association. Infection may cause fetal stress, leading to the release of meconium. MSAF may enhance the growth of bacteria by providing a rich medium of essential nutrients or growth stimulants. MSAF also may impair the host immune system so that chemotaxis or phagocytosis is diminished, thus allowing accelerated growth of microorganisms.     

Significance of meconium-stained amniotic fluid in the preterm population.

OBJECTIVE: Numerous studies have assessed the significance of meconium-stained amniotic fluid (MSAF) at term. However, to date, there has been very little documentation on the incidence and significance of meconium in the preterm population. Our objective was to define the incidence of MSAF in patients delivering prematurely (<37 weeks) and examine its association with underlying fetal acidosis, Apgars and admission to the neonatal intensive care unit (NICU). METHOD: All patients delivering at a single tertiary care center between June 1994 and September 1997 were reviewed for the presence of meconium and gestational age <37 weeks at delivery. Maternal demographics and birth outcomes including cord gases, Apgar scores and admission to the NICU were collected. Exclusion criteria included multiple gestations, breech presentations, fetal anomalies and patients not in labor. RESULTS: Out of a total of 9570 patients there were 506 (5.3%) preterm births meeting the inclusion criteria, of whom 24 (4.8%) had MSAF noted either during labor or at delivery. Comparing the preterm group with and without meconium, there were no differences in maternal age, gravidity, rate of Cesarean section, or gestational age at delivery. Cord pH (7.27 meconium vs. 7.29 no meconium) and base excess (-5.1 meconium vs. -4.0 no meconium) were similar in both groups. There were no clinically significant differences in mean Apgar scores at 1 and 5 minutes. However, an increased number of NICU admissions were noted in the group with meconium (75% vs. 53%, p=0.04). CONCLUSION: The incidence of meconium staining of the amniotic fluid in labor in the preterm population is less than 5% and by itself is not a significant marker of fetal acidosis.     

Meconium stained fluid: approach to the mother and the baby

Meconium aspiration syndrome (MAS) is a common problem that most pediatricians will encounter in the delivery room and normal newborn nursery. Approximately 13% of all live births are complicated by meconium stained amniotic fluid (MSAF). MAS is defined as respiratory distress in an infant born through MSAF whose symptoms cannot be otherwise explained. Optimal care for an infant born through MSAF involves cooperation between the obstetrician and pediatrician, each with separate but imperative roles.     

Significance of assay of nucleated RBCs in umbilical cord blood in neonates with meconium-stained amniotic fluid

Background: Approximately 8–15% of all infants are born with evidence of meconium-stained amniotic fluid (MSAF). MSAF is a potentially serious sign of fetal compromise and may indicate fetal hypoxia

Objectives and aim of the work: The present study was designed to evaluate the relationship between meconium stained amniotic fluid and fetal nucleated red blood cell counts. As well, we aim to evaluate the relationship between the presence of meconium in amniotic fluid and Apgar scores in neonates.

Subjects and methods: A prospectively case-controlled study was performed on 40 women with clear amniotic fluid as control and 40 women with meconium-stained amniotic fluid as the study group. At delivery, 2?ml of umbilical cord blood was collected and analyzed for nucleated red blood cell (NRBC).

Results: The mean NRBC counts in meconium-stained amniotic fluid was significantly higher than the control group (18.35?±?7.7 and 9.6?±?4.96), respectively (p?p?Conclusion: Our results support previous studies which indicate the presence of meconium can be associated with chronic fetal hypoxia as demonstrated by elevated fetal NRBC levels.     

Hematologic parameters in the cord blood labor complicated by meconium-stained amniotic fluid

The aim of our study was to compare hematological values of the cord blood in the presence and absence of meconium-stained amniotic fluid (MSAF). MSAF was associated with decreased total platelet count, increased values of platelet distribution width and red blood cell distribution width. The mean nucleated red blood cells was significantly higher in meconium group. The values of red blood cells, white blood cells, reticulocytes counts and their fractions (HFR,MFR,LFR,IFR) were no different in cord blood of neonate exposed to meconium and in those who were not. These findings can suggest that MSAF contribute to fetal infection rather than hypoxia.     

Meconium-stained amniotic fluid in term pregnancies-a clinical view.

The objective of this study was to explore details of the clinical relationship between meconium-stained amniotic fluid (MSAF) in labour, abnormal fetal heart pattern and meconium aspiration (MA). This was a prospective study carried out in Princess Badeea Teaching hospital during a 6-month period from March to September 1997. During the study period 344 (8.5%) of the deliveries had MSAF (344 women). Continuous fetal heart monitoring was routinely used and 36 women with MSAF (10.5%) needed to be delivered by caesarean section because of fetal distress (diagnosed by abnormal fetal heart pattern) in early labour, compared with 0.95% in those with clear amniotic fluid (CAF), (P <0.00001). Many infants in the MSAF group had a low Apgar score and required ventilation at birth. Nineteen infants (5.5%) developed MA, three of whom (15.8%) died. We conclude that there is an association between MSAF, abnormal fetal heart pattern in labour and a low Apgar score and that it should be considered a high risk situation. MA a problem that occurs with particulate meconium was significantly related to abnormal fetal heart pattern and longer length of labour.     

Secreted phospholipase A2 is increased in meconium-stained amniotic fluid of term gestations: potential implications for the genesis of meconium aspiration syndrome

Abstract

Background: Meconium-stained amniotic fluid (MSAF) represents the passage of fetal colonic content into the amniotic cavity. Meconium aspiration syndrome (MAS) is a complication that occurs in a subset of infants with MSAF. Secreted phospholipase A₂ (sPLA₂) is detected in meconium and is implicated in the development of MAS. The purpose of this study was to determine if sPLA₂ concentrations are increased in the amniotic fluid of women in spontaneous labor at term with MSAF.

Materials and methods: This was a cross-sectional study of patients in spontaneous term labor who underwent amniocentesis (n?=?101). The patients were divided into two study groups: (1) MSAF (n?=?61) and (2) clear fluid (n?=?40). The presence of bacteria and endotoxin as well as interleukin-6 (IL-6) and sPLA₂ concentrations in the amniotic fluid were determined. Statistical analyses were performed to test for normality and bivariate analysis. The Spearman correlation coefficient was used to study the relationship between sPLA₂ and IL-6 concentrations in the amniotic fluid.

Results: Patients with MSAF have a higher median sPLA₂ concentration (ng/mL) in amniotic fluid than those with clear fluid [1.7 (0.98–2.89) versus 0.3 (0–0.6), p?<?0.001]. Among patients with MSAF, those with either microbial invasion of the amniotic cavity (MIAC, defined as presence of bacteria in the amniotic cavity), or bacterial endotoxin had a significantly higher median sPLA₂ concentration (ng/mL) in amniotic fluid than those without MIAC or endotoxin [2.4 (1.7–6.0) versus 1.7 (1.3–2.5), p?<?0.05]. There was a positive correlation between sPLA₂ and IL-6 concentrations in the amniotic fluid (Spearman Rho?=?0.3, p?<?0.05).

Conclusion: MSAF that contains bacteria or endotoxin has a higher concentration of sPLA₂, and this may contribute to induce lung inflammation when meconium is aspirated before birth.     

Meconium-stained amniotic fluid and neonatal morbidity in near-term and term deliveries with acute histologic chorioamnionitis and/or funisitis.

OBJECTIVE: To determine the incidence of meconium-stained amniotic fluid (MSAF) and neonatal morbidity in near-term and term deliveries with histologic acute chorioamnionitis and/or funisitis compared to those with normal placental histology. STUDY DESIGN: In a retrospective case-control design, we compared the incidence of MSAF and neonatal outcome in 45 cases of acute histologic chorioamnionitis and/or funisitis with 89 cases of normal placental histology. We reviewed the obstetric and neonatal records for perinatal complications and neonatal morbidity. RESULTS: Mean birthweights (3372+/-473 vs 3287+/-518 g) were similar in infants born to mothers with histologic chorioamnionitis and/or funisitis compared to infants born to mothers with normal placental histology. The incidence of MSAF was significantly higher in the group with acute chorioamnionitis/funisitis (p<0.05). Similarly, the incidence of admissions to newborn intensive care unit, respiratory distress, meconium aspiration syndrome, and presumed sepsis was also significantly higher (p<0.05) in this group. CONCLUSION: The incidence of MSAF and neonatal morbidity is higher in the presence of acute inflammation of placental membranes. The presence of meconium in the amniotic fluid should alert the physician to the potential for infection and increased neonatal morbidity.     

Meconium-stained amniotic fluid

Passage of meconium usually occurs within 48 hours after birth. However, some fetuses may pass meconium in-utero leading to meconium staining of amniotic fluid (MSAF). The vast majority of fetuses pass meconium in-utero due to the physiological maturation of the fetal gut with advancing gestation leading to normal defaecation in utero. However, clinicians need to exclude ‘non-physiological’ causes of MSAF, especially an ongoing hypoxia or chorioamnionitis, to improve perinatal outcomes. Meconium aspiration syndrome (MAS) is a potentially serious fetal condition with increased risk of severe morbidity and mortality. The use of the cardiotocograph (CTG), timely recognition of ongoing hypoxia or infection, consideration of the overall clinical picture and avoidance of injudicious use of oxytocin may help avoid poor perinatal outcomes and resultant medico-legal consequences.     

Indomethacin activity in the fetal vasculature of normal and meconium exposed human placentae

OBJECTIVE: To study the effect of indomethacin on the vasculature of isolated perfused human placental cotyledon in normal and meconium pretreated placentae. STUDY DESIGN: Isolated placental cotyledons were dually perfused and fetal perfusion pressure was used as an index of vascular resistance. Meconium-stained amniotic fluid (MSAF) was collected from patients after artificial rupture of membranes, diluted 1:2, 1:4, 1:16 and 1:32 and a spectrophotometric determination of meconium concentration in amniotic fluid was performed. Only MSAF with an optical density of 20.0 units per gram was used in this study. In five placentae, the effect of indomethacin (100 microg/ml continuous perfusion from the fetal site) on basal pressure of the fetal-placental vasculature was established. In five more placentae, the effect of indomethacin on MSAF-induced vasoconstriction was established when a bolus injections of 1 ml MSAF was made into the fetal circulation. The statistical significance of response to MSAF injection was determined by paired t-test and ANOVA repeated measurements. RESULTS: A significant vasoconstrictor response to MSAF was achieved in normal placentae. Bolus injections of MSAF into the fetal circulation resulted in a significant increase in perfusion pressure (P=0.0026). Indomethacin was capable of significantly reducing the basal perfusion pressure (P=0.03). Significant attenuation of vasoconstrictor response to MSAF occurred in the presence of indomethacin (P=0.0016). CONCLUSION: Indomethacin causes a significant reduction in basal pressure of fetal placental vasculature in the human placental circulation in vitro and is capable of attenuating the vasoconstrictory activity of MSAF. The mechanism of such activity may be explained partially by the inhibitory effect of indomethacin on the PG-mediated pathways.     

Risk of meconium-stained amniotic fluid in different ethnic groups.

BACKGROUND: Recent studies indicate that the risk of meconium-stained amniotic fluid (MSAF) varies in different ethnic groups. This study prospectively examined the ethnic variation of MSAF and meconium aspiration syndrome, adjusting for gravidity, gestational age (GA), and birth weight. METHOD: The study population consisted of 6901 consecutive live births and included 31 different nationalities, seven main ethnic (race) groups, gravidity between 1 and 19, GA between 22 and 44 weeks, and birth weights between 350 and 6292 gm. RESULTS: The overall incidence of MSAF was 19% (13% thin, 6% thick). The prevalence of meconium aspiration syndrome was 5% in thick MSAF and none in thin MSAF. The incidence of MSAF differs significantly by ethnicity (14% to 30%), gravidity (17% to 23%), GA (6% to 46%), and birth weight (11% to 28%). Multivariate logistic regression analysis using the same variable showed that being black African, post-term, with a gravidity of > or = 7 and a birth weight of > or = 4000 gm significantly increased the chance for MSAF but not meconium aspiration syndrome. After controlling for these clinical variables, the black African infants had a higher percentage of MSAF at all GAs compared with the other ethnic groups. CONCLUSION: This study showed that the risk of MSAF varied by ethnicity and increased with higher gravidity, a GA of > 42 weeks, and a birth weight of > or = 4000 gm The higher incidence of MSAF without an increase in meconium aspiration syndrome in some ethnic groups may indicate advancing maturity of the gastrointestinal system in black ethnic groups compared with others of the same GA.     

Incidence of meconium aspiration syndrome in term meconium-stained babies managed at birth with selective tracheal intubation.

The delivery room management of infants born through meconium stained amniotic fluid (MSAF) remains controversial. The aim of this prospective study was to evaluate maternal and neonatal characteristics of MSAF infants and the incidence of meconium aspiration syndrome (MAS) in routine delivery room management which reserved selective intubation for depressed/asphyxiated babies. Between October 1993 and September 1997, a consecutive sample of 3745 full-term infants was analyzed. Of these, 361 were MSAF infants. No significant difference in maternal age, parity, gestational age, sex, low 1 and 5 minute Apgar scores, metabolic acidemia, or need for endotracheal intubation was found between MSAF and non-MSAF infants. Only one of the MSAF infants (0.28%), who needed intubation, developed MAS. Identification of postterm pregnancy and prenatal asphyxia is the best prevention of MAS.     

Intrapartum amnioinfusion for meconium-stained amniotic fluid: a systematic review of randomised controlled trials

BACKGROUND: Amnioinfusion (AI) is thought to dilute meconium when present in the amniotic fluid and so reduces the risk of meconium aspiration. OBJECTIVES: To evaluate if AI reduces meconium aspiration syndrome (MAS) and other indicators of morbidity in babies born to women with meconium-stained amniotic fluid (MSAF). SEARCH STRATEGY: PubMed, Medline, EMBASE, and the Cochrane Controlled Trials Register from January 1980 to May 30, 2005, using the keywords 'amnioinfusion' and 'meconium'. SELECTION CRITERIA: Randomised trials comparing AI with no AI for women in labour with MSAF. Trial quality was evaluated using pre-established criteria. DATA COLLECTION AND ANALYSIS: The following morbidity indicators were assessed: MAS, 5-minute Apgar score < 7, arterial cord pH < 7.2, and caesarean section. Studies were stratified according to the level of peripartum surveillance (standard versus limited). Typical relative risks (RRs) with their 95% confidence intervals were calculated for each outcome using a random effects model. MAIN RESULTS: In clinical settings with standard peripartum surveillance, we found no evidence that AI reduced the risk of MAS (RR 0.59, 95% CI 0.28-1.25), 5-minute Apgar score < 7 (RR 0.90, 95% CI 0.58-1.41), or caesarean delivery (RR 0.89, 95% CI 0.73-1.10). In clinical settings with limited peripartum surveillance, AI appeared to reduce the risk of MAS (RR 0.25, 95% CI 0.13-0.47). CONCLUSION: In clinical settings with standard peripartum surveillance, the evidence does not support the use of AI for MSAF. In settings with limited peripartum surveillance, where complications of MSAF are common, AI appears to reduce the risk of MAS. However, this finding requires confirmation by further studies.     

L-arginine pathway in neonates with meconium-stained amniotic fluid

Objective

To study the arginase, nitric oxide synthase and nitric oxide pathways associated with passage of meconium.

Study design

Cord blood samples were collected from 20 newborns with meconium-stained amniotic fluid (MSAF) and from 23 newborns with clear amniotic fluid. Cord blood pH, arginase, nitric oxide synthase and nitric oxide levels were compared between the groups.

Result

The differences between the arginase and nitric oxide measurements of the newborns with MSAF and those with clear amniotic fluid were significant. In the MSAF group arginase levels were significantly lower (p = 0.007) and nitric oxide levels were significantly higher (p = 0.032) than the clear amniotic fluid group.

Conclusion

Hypoxia may be involved in the pathogenesis of meconium passage due to decreased arginase and increased nitric oxide levels.     

Intrapartum suctioning of meconium: comparative efficacy of bulb syringe and De Lee catheter

Intrapartum suctioning of the newborn's pharynx with a De Lee catheter (DL) has reduced the incidence of meconium aspiration syndrome (MAS) in neonates born with meconium staining of the amniotic fluid. However, the bulb syringe (BLB) is used more often for this purpose because of greater technical convenience. In a prospective study, 60 offspring of such deliveries received intrapartum pharyngeal suctioning either by BLB (29 cases) or by DL (31 cases), according to random selection. The presence and amount of meconium in the trachea, incidence and severity of MAS, and mortality from the disease were similar between the two groups. This study suggests that the BLB is as effective as the DL for intrapartum removal of nasopharyngeal meconium in deliveries with meconium staining of the amniotic fluid. Since the BLB is easier to use, less expensive and probably safer, our results suggest that it may be the preferable method.     

Intrapartum and postdelivery management of infants born to mothers with meconium-stained amniotic fluid: evidence-based recommendations

The article reviews and critically evaluates the available evidence to determine whether the current recommendations for the management of infants born through meconium stained amniotic fluid (MSAF) should be maintained. Authors provide evidence-based recommendations regarding the benefits of amnioinfusion prior to delivery, oral suctioning of the newborn prior to delivery of the shoulder, and the practice of routine endotracheal suctioning of the newborn born through MSAF in preventing meconium aspiration syndrome (MAS). Authors also discuss the gaps in knowledge in all the above interventions to prevent MAS.     

The effect of meconium staining of amniotic fluid on the growth of Escherichia coli and group B streptococcus.

OBJECTIVE: To compare the effect of meconium staining on the growth rate of Escherichia coli and group B streptococci (GBS) in amniotic fluid. STUDY DESIGN: Sterile meconium was added in different concentrations to pooled sterile amniotic fluid obtained from term mothers. Meconium concentration was equal to: 1, 1.5, 3, 6, and 12 mg meconium/ml amniotic fluid. Amniotic fluid was quantitatively inoculated with E. coli and GBS type II and type III organisms (10(3) organisms/ml). Clear amniotic fluid and Todd-Hewitt broth served as controls. Growth rates of organisms were measured at 2, 4, 6, 8, and 24 hours after inoculation. RESULTS: Clear amniotic fluid was completely inhibitory for growth of E. coli even after 24 hours of incubation. In contrast, after 6 hours of incubation, significantly increased growth of GBS occurred (10(5) organisms/ml) (p<0.0001). The inhibitory effect on E. coli was observed even with meconium concentration of up to 1.5 mg/ml. In contrast, even the smallest concentration of meconium (1 mg/ml) resulted in a 2-log fold increase of GBS within 4 hours. The more rapid growth rate of GBS compared to E. coli persisted even at moderate staining of amniotic fluid (6 mg/ml) in the first 8 hours of incubation (p<0.005). In the presence of thick meconium (12 mg/ml), during the first 6 hours of incubation, the growth rates of GBS and E. coli were nearly similar. CONCLUSIONS: GBS (type II and III) growth, in contrast to E. coli, was less inhibited by amniotic fluid, occurred at a more rapid rate, and was enhanced at lower concentrations of meconium. As such, the presence of even light meconium staining in cases of rupture of membranes of even less than 6 hours in a mother who is a GBS carrier should be considered as a risk factor for the development of perinatal GBS infection.