Management of meconium-stained amniotic fluid.

Meconium staining of the amniotic fluid will always be a common problem. Although several therapies may be of benefit in preventing MAS, most require further rigorous scientific investigation to assess their potential in preventing this disorder.     

Intrapartum transcervical amnioinfusion for meconium-stained amniotic fluid.

OBJECTIVE: To assess the rates of cesarean deliveries and perinatal outcome following intrapartum transcervical amnioinfusion in women with meconium-stained amniotic fluid (MSAF) in a setting with no electronic fetal monitoring or specialized neonatal care. MATERIALS AND METHODS: In this prospective comparative study with 150 women who were in labor and had MSAF, 50 of the women received a transcervical amnioinfusion and the remaining 100 women received standard care. The inclusion criteria were a pregnancy of at least 37 weeks' duration, a single live fetus in cephalic presentation, no major medical or obstetric complications, and no known fetal malformation. The amnioinfusion was performed with 1000 mL of normal saline solution through a red rubber catheter. RESULTS: Amnioinfusion was associated with a significant decrease in the incidence of low Apgar score (<7) at 1 min (12% vs. 47%; relative risk [RR], 0.26; 95% confidence interval [CI], 0.12-0.56); low Apgar score at 5 min (4% vs. 23%; RR, 0.17; 95% CI, 0.04-0.71); and meconium aspiration syndrome (4% vs. 18%; RR, 0.22; 95% CI, 0.05-0.92). There was also a trend towards a lesser incidence of cesarean deliveries (18% vs. 30%; RR, 0.6; 95% CI, 0.31-1.16) and perinatal deaths (4% vs. 13%; RR, 0.31; 95% CI, 0.07-1.31). The incidence of maternal hospital stays longer than 3 days was significantly lower in the amnioinfusion than in the control group (24% vs. 48%; RR, 0.5; 95% CI, 0.29-0.85). There were no major complications related to amnioinfusion. CONCLUSIONS: Intrapartum amnioinfusion for MSAF is a simple, safe, effective, and inexpensive procedure feasible in settings where intrapartum monitoring is limited. It is associated with improved perinatal outcome and could lower cesarean delivery rates in low-resource countries.     

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.     

Prophylactic cefazolin in amnioinfusions administered for meconium-stained amniotic fluid.

OBJECTIVE: To determine if amnioinfusion with an antibiotic solution decreased the rate of clinical chorioamnionitis and puerperal endometritis in patients with meconium-stained amniotic fluid. METHODS: Patients in labor at 36 weeks of gestation or greater with singleton pregnancies and meconium-stained amniotic fluid were randomized to receive either cefazolin, 1 g/1,000 mL, of normal saline (n = 90) or normal saline (n = 93) amnioinfusion. Rates of clinically diagnosed chorioamnionitis and endometritis and of suspected and culture-proven neonatal infection were determined. RESULTS: Between the study and control groups, the incidences of clinical chorioamnionitis (7.8% vs. 8.6%), endometritis (2.4% vs. 3.5%), aggregate intrauterine infection (10.0% vs. 11.8%), suspected neonatal infection (17.8% vs. 21.5%), and proven neonatal infection (0.0% vs. 2.2%) were not significantly different. CONCLUSIONS: Prophylactic use of cefazolin in amnioinfusions did not significantly reduce rates of maternal or neonatal infection in patients with meconium-stained amniotic fluid.     

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.     

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 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.     

羊水乳酸水平对羊水粪染病例胎儿窘迫的诊断价值

目的探讨羊水乳酸水平在羊水粪染病例中诊断胎儿窘迫的临床价值。方法2003年8月至2004年12月暨南大学第二临床医学院测定72例第一产程活跃期出现羊水粪染(观察组)和52例羊水清、胎儿监护图形正常且有良好新生儿结局(对照组)的羊水及新生儿脐动脉血乳酸水平。结果对照组羊水乳酸值近似正态分布,其95%参考值为5.4~8.9mmol/L。对照组活跃期和分娩时羊水乳酸水平差异无显著性意义(P>0.05)。羊水Ⅲ度粪染的羊水乳酸水平明显高于对照组(P<0.01)。羊水Ⅰ度及Ⅱ度粪染而胎儿监护正常的病例羊水乳酸值与对照组比较,差异无显著性意义(P>0.05)。但羊水Ⅱ度粪染合并胎心基线异常或(和)重度变异减速病例的羊水乳酸水平明显升高(P<0.01)。观察组发生胎儿窘迫及新生儿窒息的病例,其活跃期羊水乳酸水平均明显高于对照组(P<0.01)。以活跃期羊水乳酸值>8.9mmol/L为异常值来诊断胎儿窘迫发生的敏感性、特异性、阳性预测值及阴性预测值分别为61.9%、88.2%、68.4%和84.9%。结论羊水乳酸值测定对提高羊水粪染病例胎儿窘迫的诊断准确性有一定临床价值。     

The effect of meconium-stained amniotic fluid on perinatal outcome in pregnancies complicated by preterm premature rupture of membranes

Archives of Gynecology and Obstetrics - To determine whether meconium-stained amniotic fluid (MSAF) encountered in pregnancies complicated by preterm premature rupture of membranes (PPROM) is...     

Does amnioinfusion reduce caesarean section rate in meconium-stained amniotic fluid

Introduction  

The purpose of our study was to evaluate the safety and efficacy of transcervical amnioinfusion during labour complicated by meconium-stained amniotic fluid, in a setting with limited peripartum facilities, to lower the incidence of caesarean section.     

羊水粪染的羊水置换与新生儿预后

目的 对Ⅱ度以上羊水粪染的孕妇行羊水置换,旨在改善新生儿预后。方法 ３２例采用自行设计的三通管装置和置换液行羊水置换,作研究组,另３０例作对照组,进行对比分析。结果 新生儿窒息率、胎粪吸入综合征发生率、脐血及股动脉血血气分析,研究组与对照组对比有显著性差异（Ｐ〈０．０１）。产褥病率两组无明显差异（Ｐ〉０．０５）。两组各自脐静脉和股动脉血血气分析对比无显著性差异（Ｐ〉０．０５）。结论 羊水染行羊水和     

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.     

The utility of amnioinfusion in the prophylaxis of meconium-stained amniotic fluid infectious morbidity

Objectives: To evaluate the utility of intrapartum amnioinfusion (AI) in reducing the infectious morbidity of patients with meconium-stained fluid (MSF). Previous studies have shown increased intraamniotic infection (IAI) and postpartum endometritis (PPE) rates in patients with MSF. Intraamniotic infection has been reduced with the prophylactic administration of ampicillin-sulbactam in MSF. Intraamniotic infection and PPE have been reduced with the use of AI in patients with clear fluid. No investigators have specifically examined the efficacy of AI in reducing meconium-stained, amniotic-fluid-associated infectious morbidity.Methods: A retrospective cohort study of all cases of MSF was conducted and included patients who delivered at Louisiana State University Medical Center-Shreveport during the one-year period from January to December 1996. Patients were identified from the perinatal database by the diagnosis code of MSF. The medical records were reviewed to determine the consistency of MSF and the presence or absence of infectious morbidity. Patient demographics, labor characteristics, and various risk factors for infection were sought. The main outcome measures were the occurrence of clinical IAI or PPE. Statistical analysis included two-tailed unpaired t-test, X(2), ANOVA, and Fisher exact test when appropriate.Results: Two hundred seventy-three medical records of patients with MSF were studied. One hundred twenty nine patients received AI, and 144 did not receive AI. No significant differences in demographics, labor characteristics, or outcome variables were noted between the two groups. The incidences of IAI were 18.6% and 24.3%, P = 0.13, in the AI and non-AI groups, respectively. Postpartum endometritis occurred in 22.5% of AI patients and 21.5% of non-AI patients, P = 0.97.Conclusions: The use of AI confers no benefit for the reduction of infectious morbidity in patients with MSF.     

Endothelin-1 concentrations in cord blood of neonates with meconium-stained amniotic fluid

BACKGROUND: The effects of meconium-stained amniotic fluid (MSAF) on cord blood endothelin-1 (ET-1) concentrations have not been explored. OBJECTIVE: The aim of this study was to verify whether MSAF influences ET-1 cord blood concentrations in healthy term neonates. METHODS: Using an enzyme-linked immunosorbent assay, plasma ET-1 concentrations were determined in 30 healthy term neonates with MSAF, and in 15 healthy term neonates without MSAF. The two groups were of the same gestational age, weight, Apgar score, cord blood pH, base excess, and hematocrit values, as well as systolic and diastolic blood pressures. RESULTS: ET-1 plasma concentrations were not significantly different between the two groups and did not correlate with cord blood pH or base excess values. CONCLUSION: Our data demonstrate that meconium passage does not induce ET-1 secretion.