Meconium aspiration syndrome (MAS) frequently occurs in neonates born in thick meconium-stained liquor (TMSL). It continues to be a significant cause of neonatal morbidity and mortality despite aggressive approaches to intervention. This study aims to identify the perinatal characteristics of deliveries with TMSL associated with the development of MAS and to describe the outcome of those babies who developed MAS.
All newborns with TMSL born in Hospital Alor Setar, Kedah from 1 October 1998 to 30 April 1999 were prospectively studied. In the hospital, all newborns with TMSL were routinely admitted to the Special Care Nursery for observation. Relevant data regarding pregnancy, delivery, resuscitation and outcome of newborns with and without MAS were collected and analysed. The incidence of TMSL among hospital deliveries was 2.2% (95% C.I. 1.8-2.5%). Thirty-six percent (95% C.I. 28.4-44.7%) of newborns with TMSL developed MAS. Significant risk factors associated with the development of MAS were non-Malay mothers (p=0.04, OR=3.32), resuscitation by paediatric medical officers (p=0.02, OR=2.84) and direct tracheal suction during resuscitation (p=0.02, OR=2.61). The presence of non-Malay mothers or resuscitation by paediatric medical officers or direct tracheal suction during resuscitation gave a sensitivity of 88.2%, specificity of 36.7%, a positive predictive value of 44.1% and a negative predictive value of 84.6% for the development of MAS. Asphyxia, pneumothorax and persistent pulmonary hyper-tension occurred in 25.5%, 7.8% and 5.9% of the babies with MAS respectively. Mechanical ventilation was required in 51% and the mortality rate was 3.9%. In conclusion, the incidence of TMSL and MAS and the mortality rate of neonates with MAS were comparable with that in developed countries. The presence of any one of the significant risk factors had high sensitivity but low specificity for the development of MAS. Newborns were unlikely to develop MAS if all these risk factors were absent.