cesarean section AQP9 4 AQP9 protein, human 4 Adult 4 Aquaporins 4 Article 4 Female 4 Humans 4 Pregnancy 4 Trophoblasts 4 adult 4 aquaporin 4 aquaporin 9 4 controlled study 4 female 4 gene expression 4 gene expression regulation 4 genetics 4 human 4 human tissue 4 immunoblotting 4 messenger RNA 4 metabolism 4 placenta 4 pregnancy 4 priority journal 4 protein expression 4 trophoblast 4 upregulation 4 Cesarean Section 2