The effect of increased amnion volume severity on fetal Doppler indices and perinatal outcomes in idiopathic polyhydramnios

Aim: To evaluate the relationship between polyhydramnios severity and alterations in Doppler indices and perinatal outcomes in idiopathic polyhydramnios. Methods: This prospective case control study was conducted in a tertiary hospital with 173 singleton pregnancies between 29 and 41 weeks gestational age between May 2015 and December 2016. Polyhydroamnios is classified as mild (amniotic fluid index 25-30 cm), moderate (30.1-35 cm), and severe (>35 cm) and the number of the patients in mild, moderate, and severe groups were 55, 39, and 26, respectively. The results were compared with 53 healthy controls. Fetal echocardiography and Doppler measurements of the groups were made and the perinatal outcomes from each group were noted. The relationship between the results and the severity of polyhydramnios was analyzed statistically. Results: The myocardial performance index was significantly higher in the fetuses of women with severe polyhydramnios compared to the other groups (p = .006). There were statistically significant differences among the groups in terms of first and fifth minutes according to the Apgar scores (p = .011, p = .016 respectively). In the severe polyhydramnios group compared with other groups, the middle cerebral artery pulstatility index was significantly lower (p = .002), while middle cerebral artery peak systolic velocity and umbilical artery pulstatility index values were significantly higher (p = .0001, p = .045). Conclusions: Our study showed an increase in myocardial performance index and middle cerebral artery peak systolic velocity values and a decrease in middle cerebral artery pulstatility index values, especially in the severe idiopathic polyhydramnios group. Idiopathic polyhydramnios were associated with low first and fifth minute Apgar score. Additionally, the increase in umbilical artery pulstatility index value and the decrease in middle cerebral artery pulstatility index value became more apparent with the increase in amniotic fluid volume. It should be taken into consideration that brain sparing effect may develop especially in cases with severe polyhydramnios.