Intravenous maternal hydration in third trimester oligohydramnios: effect on amniotic fluid volume

Abstract

Objective: To determine the affect of acute intravenous maternal hydration on amniotic fluid volume in patients with third trimester oligohydramnios.

Study design: Quasi experimental study.

Place and duration of study: Department of Obstetrics and Gynaecology Unit III, Sir Ganga Ram Hospital, Lahore, from May 2001 to April 2002.

Patients and methods: Twenty-five women with third trimester oligohydramnios (AFI < or = 5.0 cm) and 25 controls with normal amniotic fluid volume (AFI 8-24 cm) were prospectively recruited for this study. Study inclusion criteria were, singleton pregnancy, well-established gestational age, intact membranes, absence of maternal complication (anemia, cardiac disease, renal disease, pre-eclampsia, hypertension, or diabetes); absence of fetal structural malformation and/or distress. Maternal urinary specific gravity and amniotic fluid index were determined before and after intravenous hydration by infusing 2 liters of 5% dextrose water in 2 hours and recorded on printed proformas. Sample independent 't' test was used to compare the mean AFI and urine specific gravity before and after treatment, and the posttreatment AFI--pre-treatment AFI ( delta AFI).

Results: Maternal hydration increased amniotic fluid volume (AFV) in women with oligohydramnios (mean change in amniotic fluid index 4.5 cm, 95% confidence interval 4.02 to 5.06; p-value<0.01); as well as in women with normal amniotic fluid volume (mean change in amniotic fluid index 2.7 cm, 95% confidence interval 2.23 to 3.21; p-value<0.01). The percentage increase in mean AFI was 58.6% in the oligohydramnios group, which was significantly greater (p<0.05) than the percentage increase of 28.4% in control group. Maternal hydration was associated with decrease in urinary specific gravity in both groups.

Conclusion: Under the conditions of this study, maternal (intravenous) hydration increased the AFV in women with oligohydramnios as well as in those with normal AFV and may be beneficial in the management of oligohydramnios.