The aetiology of meconium-stained amniotic fluid: pathologic hypoxia or physiologic foetal ripening? (Review).

Introduction: Despite the many efforts to study the (patho)physiology of meconium release before delivery, it still remains an indistinct subject. Some studies have reported a relationship between hypoxia and MSAF, whilst others have not. The most common association found however, is between MSAF and the term of gestation.

Methods: MEDLINE, EMBASE and the Cochrane library were electronically searched. Papers about the (patho)physiology of meconium-stained amniotic fluid in English were included. Papers about management strategies were excluded (see elsewhere this issue).

Results: Different theories have been proposed including acute or chronic hypoxia, physiologic foetal ripening and peripartum infection.

Conclusion: We suggest that meconium-stained amniotic fluid should be regarded as a symptom rather than a syndrome becoming more prevalent with increasing term and which might be associated with higher levels of infection or asphyxia.