and relaxing the anal sphincter, which results in the passage of meconium. Then, because of intrauterine gasping or from the first few breaths after delivery, MAS may develop. Furthermore, aspiration of thick meconium leads to obstruction of airways resulting in a more severe hypoxia.

The association between foetal distress and meconium passage is not a definite cause-effect relationship as over 3/4 of infants with MSAF are vigorous at birth and do not have any distress or hypoxia. Additionally,