Risk Factors and Outcome of Neonates Born through Meconium Stained Amniotic Fluid in a Tertiary Hospital of Nepal

Address for correspondence: Dr. Simmi M Gurubacharya Paropakar Maternity and Women’s Hospital Department of Neonatology, Kathmandu, Nepal Phone No.: +977 9841560911 Email: drsimmimg@gmail.com 1Dr Simmi Misra Gurubacharya, Chief Registrar, Associate Professor, 2 Dr Shistata Rajbhandari, Medical Officer, 3 Dr Roshma Gurung, Medical Officer, 4Dr Asha Rai, Medical Officer, 5Dr Megha Mishra, Medical Officer, 6Dr Kamal Raj Sharma, Senior Consultant, 7Dr Dhana Raj Aryal, Chief Consultant, Head of The Department. All from the department of Neonatology, Paropakar Maternity and Women’s Hospital, Kathmandu, Nepal. Abstract


Introduction
M econium Aspira on Syndrome (MAS) is an important cause of morbidity and mortality among newborns in the developing world.Meconium stained amnio c fl uid (MSAF) occurs in approximately 13% of all live births 1 .Presence of meconium is a sign of fetal distress warran ng immediate evalua on and ac on.It can lead to MAS.MAS is defi ned as respiratory distress in an infant born through MSAF whose symptoms otherwise cannot be explained 2 .It leads to poor lung compliance, hypoxemia leading to respiratory distress with complica ons like respiratory failure, pulmonary air leaks and persistent pulmonary hypertension of the newborn.Onethird of infants require intuba on and mechanical ven la on 3,4 and newer neonatal therapies like high frequency ven la on, inhaled Nitric Oxide and surfacant administra on 5,6 .The incidence of MAS, morbidity and mortality varies among countries.According to western data there has been a reduc on in the incidence of MAS in the past decade due to advances in perinatal care 7 .This has been a ributed to be er obstetric prac ces.There is paucity of data regarding the neonatal outcome of babies born through MSAF in Nepal.This study is aimed to assess the perinatal a ributes, mortality and morbidity associated with babies born through MSAF.The study would refl ect the prenatal and postnatal care of babies delivered through MSAF and the improvement as required in the perinatal health services so that adverse outcome is prevented as well as minimized especially at the regional level II/III perinatal centre.

Materials and Methods
All live babies born though MSAF over dura on of three months from April 2010 to June 2010 were enrolled.This was a cross-sec onal study.To assess the risk factors related with MSAF deliveries and MAS all the details regarding mode of delivery, APGAR score (AS), birth weight, fetal distress, birth asphyxia, maternal age, any maternal illness and parity, me of rupture of membranes, gesta onal age, chest radiograph fi ndings, clinical course, outcome and mechanical ven la on (MV) as needed were recorded and evaluated.Newborns with gross congenital anomalies were excluded.Risk es ma on analysis for MAS was done by calcula ng Odd's Ra o (OR) and Bivariate Analysis.

Results
There were total 5641 live births over a period of three months.Out of these deliveries 824 babies were born through MSAF which es mates to be 14.6%.Owing to the lack of complete data 27 babies were excluded.Among 797 babies born through MSAF, 53 developed MAS i.e.6.6%.Table 1 show diff erent variables studied as risk factors for MAS.Among all the variables APGAR score at 1 minute and 5 minute, premature rupture of membranes (PROM) and need of mechanical ven la on were signifi cant variables associated with increased risk of MAS in the babies born through MSAF by Chisquare test.Table 2 shows the bivariate analysis further done that revealed APGAR score at 1 minute and 5 minute, need of resuscita on and PROM as signifi cant factors contribu ng to increased incidence of MAS.The clinical outcome is shown in Table 3. Neonates born through meconium stained liquor were diagnosed and categorized as shown in Table 4.Among the category of others, condi ons like congenital heart diseases, intrauterine pneumonia, neonatal depression and suspected case of spinal muscular atrophy were present.

Discussion
In the study MSAF deliveries were 14.6% and out of all the neonates born through MSAF, 6.6% developed MAS.The occurrence of MSAF varied from 7.9% to 18% 8,9,10,12 in other studies.The study done by Bhat RY 11 showed MAS occurred in 11.3% of babies born through MSAF while in other studies it varied from 1% to 38.5% 8,9,10,12,13 .Seventeen percent of the babies among MAS group required mechanical ven la on and three newborns were referred due to the ven lators being occupied.Among all the neonates born through MSAF 41.8% were born through normal vaginal delivery, 49.4% through caesarean sec on and 8.7% by assisted delivery, vacuum being the commonest method.Out of all the babies who developed MAS 39.6% were born through normal vaginal delivery, 47.1% born through caesarean sec on and 13.2% through assisted vaginal delivery.Mode of delivery was not found to be a signifi cant risk factor for MAS.Some of the studies 12 do not refl ect caesarean delivery as the signifi cant risk factor while other studies showed it as the signifi cant risk factor for MAS 7,14 .82% of the mother belonged to the age group of 20 to 34 years and those mothers who developed MAS 83% were in the age group of 20 to 34 years.Age of the mother, parity and birth weight of babies did not show signifi cant associa on with MAS similar to other authors 12,14 while few studies showed the associa on for the parity 9,15 .Although there was increased incidence of MSAF and MAS in the post dated group between 40 to 42 weeks but the gesta on was not signifi cantly associated with increased incidence of MAS as seen in other studies 7,14 .The number of post term pregnancy was quite less as compared to other gesta onal groups probably our hospital being a ter ary hospital and interven on is done mely before the pregnancy could reach post term.Fischer C et al 14 found in their study gesta onal age as main risk factor of MAS but the incidence of MAS in neonates born through MSAF did not depend on gesta onal age.
Bivariate analysis showed APGAR score at 1 minute, 5 minute, PROM and need of resuscita on as signifi cant factors contribu ng to increased incidence of MAS.Peter AD 7 found in Australian live births a very strong associa on with a 5 minute APGAR score<7 with an overall Odd's ra o of 52.Similar observa on was made by Bhat RY, Liu WF in their study where they found APGAR score at 1 minute and 3 minutes as signifi cant but they took APGAR score value at 1minute as 6 and at 3 minute as 7 respec vely.In another study 12 APGAR score at 5 minute < or =5 was found to be signifi cant.Meydlani MM et al 15 found APGAR score < or =6 at 5 minute (RR=3.8,95% CI=1.7-8.4) as signifi cant risk factor for MAS.Similarly others 14,16 have shown low APGAR score as main risk factor for MAS refl ec ng perinatal asphyxia as a signifi cant risk factor.Those babies requiring resuscita on had signifi cant associa on with MAS and so are refl ected by low APGAR score at 1 and 3 minute.Low APGAR score and need of resuscita on signify the need of improvement in antenatal care and preven ng perinatal asphyxia to prevent the morbidity and mortality associated with MAS. 30 % to 50% cases of MAS may require mechanical ven la on or con nuous posi ve airway pressure 17 .PROM was also a signifi cant risk for the development of MAS.In the study done by Bhaskar SH et al 9 the incidence of MAS was signifi cantly higher in mothers with PROM.This observa on refl ects that monitoring and mely interven on is needed when there is history of ruptured membranes to prevent MAS.In our study mortality among those who developed MAS was 11.3%.The mortality reported in other studies 7,11,13,18 varied from 2.5% to 33%.The mortality was high especially when compared to western data 7 .In a ter ary hospital where many obstetric cases were referred cases, along with the se ng of limited resources, inappropriate ra o of pa ent to health personnel, and limited availability of technology, decreasing morbidity and mortality is a big challenge.

Conclusion
Among all the risk factors evaluated perinatal asphyxia and PROM were iden fi ed as signifi cant in development of MAS in the neonates born through MSAF.The mortality is also high refl ec ng the need of improvement in the management of neonatal care at the ter ary level especially in the hospital where the number of high risk deliveries is more.Preven ng perinatal asphyxia through appropriate monitoring and mely delivery will be the main key to prevent MAS.When history of PROM is present mely management is needed to prevent MAS and its sequelae as shown by the study.

Table 1 :
Variables and their associa on with MAS among neonates born through MSAF *AS-APGAR score, G-Gravidarum, MSAF-Meconium stained amnio c fl uid, MV-Mechanical ven la on

Table 2 :
Risk Factors with increased incidence of MAS by Bivariate analysis *AS-APGAR score, PROM-Premature rupture of membrane

Table 3 :
Outcome of Neonates born through Meconium Stained Amnio c Fluid

Table 4 :
Final Diagnosis of Neonates born through Meconium Stained Amnio c Fluid