Intriguingly, this group subsequently discovered that in pregnancies with polyhydramnios, AQP1 expression was enhanced in all regions of the foetal membrane, demonstrating that alterations in AQP1 expression might be a compensatory response but not the primary aetiolgy of idiopathic polyhydramnios (Mann et al. 2006). This evidence concerns the gene AQP1 and Polyhydramnios.