Immediate Clinical Outcome of Newborns with Meconium Stained Amniotic Fluid in an Urban Referral Centre

Raju, V (2007) Immediate Clinical Outcome of Newborns with Meconium Stained Amniotic Fluid in an Urban Referral Centre. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION: The detection of meconium-stained amniotic fluid during labour often causes anxiety in the delivery room because of its association with increased perinatal mortality and morbidity. However, experts continue to debate whether the risk of harm is associated with the meconium itself, or whether the overall risk is increased because of the underlying condition leading to the passage of meconium. The obstetric literature is fraught with controversy and unanswered questions regarding the significance of meconium in the aminotic fluid and the appropriate management protocols that should be followed when it is discovered. It is believed by some medical experts that the passage of meconium is triggered by fetal stress, such as hypoxia or asphyxia, and that the presence of meconium in the fluid may be considered an indicator of fetal distress. Others point out that the presence of meconium in the amniotic fluid also may be a result of gastrointestinal maturity. Thus, the presence of meconium in the amniotic fluid is only one factor to be considered along with many variable and clinical markers that may help to explain the etiology and timing of irreversible brain damage. There are many variables and unanswered questions concerning the time it takes for meconium to initiate pathologic placental changes or to cause damage to umbilical cord vessels for meconium to be a useful marker to time brain injury. MECONIUM: Meconium is a thick, odorless, blackish green material, first demonstrable in the fetal intestine during the third month of gestation. It is a sterile mixture of water (75-95%), mucopolysaccharides (80% dry weight), gastrointestinal secretions (bile salts and pancreatic, liver enzymes), solids, (vernix caseosa, lanugo, and squamous cells), blood minerals and lipids (free fatty acids).It’s pH ranges from 5.5 to 7. Meconium first appears in the fetal ileum between 10 to 16 weeks of gestation1. The term meconium is derived from ancient Greek word meconium-‘arion’, or opium like, from the Greek word ‘mekoni’ meaning poppy juice. Aristotle coined the term, because he believed that the substance induced fetal sleep. INCIDENCE: Meconium staining of amniotic fluid (MSAF) occurs in approximately 10% to 26% of all deliveries, with the highest rates reported from North America1-5. Although meconium appears in the intestine very early in gestation, MSAF rarely occurs before 38 weeks of gestation. Incidence of MSAF increases thereafter and approximately 30% of newborns have MSAF if born after 42 weeks of gestation1. Meconium stained liquor is rare in premature infants (<5 percent of preterm pregnancies); if it does occur, there may be an association with infection and chorioamnionitis. The incidence of meconium aspiration syndrome varies between 1 and 5 percent of all deliveries where there has been meconium stained liquor, with higher rates reported from North America compared to Europe1-3,5. There are a number of factors associated with an increased risk of developing meconium aspiration syndrome. These include lack of antenatal care, black race, male fetus, abnormal fetal heart rate monitoring, thick meconium, oligohydromnios, operative delivery, poor activity, pulse, grimace, appearance and respiration (APGAR) scores, no oropharyngeal suctioning and the presence of meconium in the trachea. AIM OF THE STUDY: a. To find out the immediate clinical outcome of new borns with meconium stained amniotic fluid. b. Factors responsible for meconium stained amniotic fluid. DISCUSSION: 1. In our study, with respect to parity of mother the meconium stained amniotic fluid had 146 (67.28%) cases of primigravidae when compared to multigravidae (15.20%) and II gravidae. Thus primi parity is associated to MSAF, which is similar to the study conducted by David et al26. Incidence of primi is higher in our study when compared to the study of Narang et, where the incidence was 57.14% in primi and 42.86% in multigravidae5. 2.Majority of MSAF are delivered through emergency LSCS in our study with 76.49% incidence. This indicates that majority of MSAF are being delivered through caesarean section which is similar to the study of Wong et al20. 3.In our present study the major indication for LSCS in MSAF group is fetal distress, which being reported in 75 cases (48.38%). This is higher when compared to the study of Alchalabi et al, where the indication of LSCS for fetal distress was only 10.5%22. 4. There is no antenatal risk in 158 cases (74.17%) in meconium stained group. 42 cases (19.71%) had PIH as an antenatal risks and anaemia in 13 cases (6.10%). This is similar to the study of Kanula et al., where PIH was the main antepartum complication leading to meconium stained liquor. Other factors like hepatitis in mother, asthma, APH which were significant in their study was not so in our study. This is contrast to the study of Zhu et al., whom concluded that there is no correlation between MSAF and maternal medical complication21. 5. Significant fetal heart rate variability in meconium stained group is observed which is similar to the study of Sheiner et al., where they found a significant linear association between meconium stained amniotic fluid and abnormal fetal heart rate24. 6. Majority showed placental calcification in meconium stained group. This is found to be significant in our study and no previous study mentioned this as a factor in MSAF. 7. Though it was mentioned in the study of Berkus et al., that males had a preponderance of getting meconium stained liquor23, in our present study both male and female had equal change of getting MSAF., But when the consistency is considered, 75 cases (69.4%) of thin meconium are male and 43 cases (56.5%) of thick meconium are female. 8. In our present study, majority of meconium stained liquor are term babies with 215 cases (99.07%) and 2 (0.01%) are post-term and no preterm babies. This is in contrast with Zhu et al study, where they concluded that the relative factors on MSAF were gestational weeks >42 weeks and large for gestational age babies21. 9. In our study, out of 33 cases of SGA, 27 (81.8%) had MSAF. All of them are asymmetrical IUGR babies. Thus the IUGR babies had a higher incidence of MSAF when compared to AGA babies. This is comparable to previous study of Gupta et al, where IUGR was also associated with MSAF3. · In our study, thin meconium seen in 141 cases (64.8%) and thick meconium in 76 cases (35.2%). This is comparable to previous studies done by Sheiner E et al24, in which thin meconium out numbered the thick meconium. 10 The morbidity associated with thick meconium is higher in our study. Out of 20 cases of meconium aspiration (detected by x-ray). 16 cases (80%) are with thick meconium and 4 cases (20%) in thin meconium. 11. Among 10 cases who presented with respiratory failure, 8 cases (80%) had thick meconium staining and only 2 (20%) with thin meconium. 18 cases (54.5%) of thick meconium required anticovulsants along with O2, IVF and antibiotics. The need for mechanical ventilation also high in thick meconium group. Out of 10 cases which needed mechanical ventilation 8 (80%) are associated with thick meconium and only 2 (20%) with thin meconium. Seizures, MAS, airleak are more observed in thick meconium group. Out of 10 death, 8 (80%) cases are with thick meconium. This morbidities with thick meconium are similar to the study of Sheiner et al., Gonzalez et al., where they concluded that consistency of meconium had a direct bearing on neonatal outcome and thick meconium alone should alert the physician to a high risk fetal condition27. 12. Outcome of MSAF in our study is seizure in 32.1% MAS in 4.7%, Airleak in 4.7%, and death in 10% of cases. This is similar to the study of Manju Latha Sharma et al with seizures in 25.64%, airleak in 12.8% and death in 10.25% cases. CONCLUSION: Meconium staining of amniotic fluid by itself has no significance. In our study, not all the babies who were born through meconium stained amniotic fluid required admission. Only a part of them required admission. Even in the admitted babies, respiratory distress settled within few hours of supportive measures of treatment. But, meconium stained amniotic fluid becomes a significant factor when associated with factors like maternal PIH, anaemia, oligohydromnios, IUGR babies, CTG showing FHR variability and placental calcifications. In these cases MSAF is associated with morbidity and mortality; majority of which are thick meconium suggesting that consistency of meconium had direct bearing in neonatal outcome. Although mode of delivery in MSAF does not prevent meconium aspiration, majority of them are delivered through caesarean section which is questionable.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Immediate Clinical Outcome ; Newborns ; Meconium Stained Amniotic Fluid ; Urban Referral Centre.
Subjects: MEDICAL > Paediatrics
Depositing User: Ravindran C
Date Deposited: 20 Apr 2018 08:22
Last Modified: 21 Apr 2018 02:32

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