Impact of antepartum diagnostic amnioinfusion on targeted ultrasound imaging of pregnancies presenting with severe oligo- and anhydramnios: An analysis of 61 cases.

OBJECTIVES: The primary objective our study was to assess the role of diagnostic antepartum amnioinfusion on the yield from targeted ultrasounds performed in pregnancies with severe oligo- and anhydramnios.

STUDY DESIGN: This was a retrospective and descriptive study, conducted in the fetal medicine units of two private tertiary care referral centers in south India. The details of all the cases of diagnostic amnioinfusion performed at these two centers from January 2009 to June 2016 were collected and analyzed. Inclusion criteria were pregnancies between 17 and 26 weeks of gestational age with severe oligo- or anhydramnios. Pregnancies with obvious preterm premature rupture of membranes (PPROM) were excluded. The primary outcome measure was the improvement in diagnostic information pertaining to cause of severe oligo- and anhydramnios, and the nature of such anomalies.

RESULTS: A total of 61 cases of were identified. The median gestational age at performance of the procedure was 22 weeks [IQR, 19.5-23]. The mean volume of normal saline infused was 314±54ml. A significant increase in the single vertical pocket (SVP) was observed following the procedure (pre-procedure SVP=0.6±0.9cm, post procedure SVP=3.4±1.7; paired t test, p<0.001). In 37 cases (37/61, 60.7%), there were no pre-procedure ultrasound findings. There was significant overall detection of abnormalities post procedure (mean pre-procedure findings=0.39±0.49, mean post procedure findings=1.59±1.24; paired t test, p<0.001). The most frequent group of anomalies/abnormalities were renal (36/61, 59%), followed by PPROM (13/61, 21.3%) and finally fetal growth restriction (11/61, 18%).

CONCLUSION(S): Antepartum amnioinfusion is a valuable ancillary technique in prenatal diagnosis as it increases the diagnostic yield from pregnancies presenting with severe oligo- and anhydramnios.