Meconium aspiration syndrome - the experience of a tertiary center

Approximately 5 % of infants born with a meconium-stained amniotic fluid (MSAF) develop meconium aspiration syndrome (MAS).

The aims of this study were to analyse demographic data, morbidity and mortality associated with MAS and to identify possible risk factors.

Retrospective chart review of newborns with MAS delivered at a tertiary centre from January 1st, 1997 to December 31st, 2008.

MAS was responsible for 1.4 % of all Neonatal Intensive Care Unit (NICU) admissions, with a trend towards a decreasing incidence during the study duration, especially in the cases of thin meconium. Seventy two newborns were analysed during the study period: 55.6 % (n = 40) were of the female gender, 62.5 % were delivered by caesarean section, 93 % had > 36 weeks of gestational age and 91.2 % had a birth weight over 2500g. Sixty-nine percent had an Apgar score < 7 at 1 minute and 23.6 % an Apgar score < 7 at 5 minutes; foetal bradicardia was present in 26.4 % of the newborns and tachycardia in 1.4 %. The presence of meconium was associated with severe asphyxia and carried a bad prognosis with an increased risk of developing hypoxia (58.3 %), need of mechanical ventilatory support (43.1 %), respiratory and/or metabolic acidosis (30.6 %), pulmonary hypertension (11.1 %) and hypoxic ischemic encephalopathy (29.2 %). The mortality rate was 2.8 %. Thick meconium was associated with higher morbidity and mortality rates.

The number of admissions for MAS has been decreasing mostly because of a lower admission rate due to thin meconium; the number of cases with thick meconium has remained constant throughout the years. An Apgar score < 7 at 1 minute and signs of foetal distress during labour were associated with MAS. The MAS related morbidity remains significant.