Alteration of the amniotic fluid and neonatal outcome

Quantitative and qualitative alterations of the amniotic fluid complicate 7% of the pregnancies. Polyhydramnios complicates 1-3% while oligohydramnios involves 3-5% of the pregnancies. The most common causes of polyhydramnios are fetal abnormalities, maternal diabetes and twin pregnancies, but are idiopathic in the 60%. Perinatal mortality has been reported to range between 10-30% while the risk of preterm birth reaches up to 22% in pregnancies complicated by polyhydramnios. The neonatal outcome, in cases where polyhydramnios is due to fetal-neonatal abnormalities, depends on the underlying pathology. Polyhydramnios due to defects in intestinal canalisation in particular, has been correlated to good neonatal prognosis. In our experience no early postoperative deaths occurred in a group of 16 newborns consequtively admitted to our unit in the last two years, with abnormalities of the gastrointestinal tract with need of surgery within the second week of life. Most cases of oligohydramnios are due to premature rupture of membranes, other causes are fetal abnormalities, such as urinary tract malformations, or chromosomopaties and drugs e.g. NSAID's. Oligohydramnios of mild entities is often associated to preterm birth, fetal growth restriction. In some cases of oligohydramnios, neonatal survival is highly conditioned by pulmonary hypoplasia which develops with rates that range between 13 and 21%. Neonatal prognosis is often disastrous in cases with severe oligohydramnios, which however could be improved by amnioinfusion, which restores an amniotic fluid volume sufficient in reducing the adverse environmental effects and in prolonging, where possible, pregnancy. Beside the quantity also the quality of the amniotic fluid may be related to the neonatal outcome. Finding of some inflammatory factors (interleukines) in the amniotic fluid seems to be significantly correlated to periventricular leucomalacia (PVL), cerebral paralysis and long-term neurological abnormalities, both in the preterm and term neonate. Therefore, increase of the cytokines in the amniotic fluid could give information not only of the infection but also regarding the risk of developing neurological sequelae in neonatal period. Diagnosis and therapy for pathologies that alter the amniotic fluid have progressed, however efforts have still to be made in the identification and search for those quantitative-qualitative alterations of the amniotic fluid, for their potential implications on neonatal outcome.