Hydrotherapy for the Reversal of Oligohydramnios

OBJECTIVE: To assess the efficacy of subtotal immersion therapy as an option to improve maternal intravascular volume thereby improving both maternal and fetal hemodynamic status with reversal of oligohydramnios. This will be measured utilizing the Amniotic Fluid Volume (AFV) as the primary outcome. Secondary outcomes will be measured using Fetal Doppler Studies, Maternal vital signs (Blood Pressure, Pulse Pressure, Weight, Pulse) and input/output.

HYPOTHESIS: Oligohydramnios, secondary to depleted maternal intravascular volume, can be reversed by improving feto- and uteroplacental perfusion with subtotal immersion therapy.

BACKGROUND: The volume of amniotic fluid is relevant clinically as derangements that decrease volume result in a condition known as oligohydramnios, which can have profound implications on perinatal outcome. The incidence of oligohydramnios is 2.3%1,2,3 and measurements of amniotic fluid volume (AFV) has become a standard in fetal surveillance in the evaluation of high risk pregnancies as oligohydramnios is associated with intrauterine growth restriction, respiratory distress syndrome, post-maturity syndrome, and chronic fetal hypoxia. Oligohydramnios may also play a role in fetal malpresentation, umbilical cord compression, meconium staining, and increased operative delivery.3,4, 5,6 Oligohydramnios is commonly defined as an AFV of 5 cm or less. An AFV of 8 cm represents the fifth percentile of normal AFV values.7 It has been observed that delivery in the setting of isolated oligohydramnios, irrespective of an otherwise uncomplicated term gestation free of maternal disease, has become routine thereby increasing maternal morbidity particularly in context of operative delivery or failed inductions. 3

In order to understand oligohydramnios it is first important to understand intrauterine water and progressive changes that occur with normal human gestation. At term, it is reported that total water accumulation is approximately 3.5L, with 2400 mL in the fetus, 400 mL in the placenta, and 700 mL in the amniotic fluid.8 In 1989, Brace and colleagues determined amniotic fluid volume (AFV) as a function of gestational age. They reported an increase in mean values from 30mL at 10weeks to 190mL at 16wks to 780mL at 32-35wks after which time AFV decreases, especially in post-term pregnancies. It is important to realize; however, that the pattern of volume fluctuation as a function of gestational age may vary considerably between individuals. As a general rule AFV increases at a rate of 10ml/wk at the beginning of the fetal period, this rate of expansion increases to 50-60ml/wk from 19 to 25wks at which time a gradual decrease begins to take place until the rate of exchange is zero around 34wks.

The pathophysiology of amniotic fluid regulation is not entirely understood at this current date, but it is safe to state that AFV is the integrated sums of the inflow and outflow tracts of the amniotic space.8 Because fluid can move with relative ease between fetal and maternal blood across the placenta and amniotic membranes it stands to reason that a maternal hypovolemia secondary to dehydration would lead to the development of oligohydramnios. This was indeed shown to be the case by Sherer, et al in their 1990 publication. Furthermore, both oral and serum hydration as a way to increase maternal volume have been shown to be effective treatments for oligohydramnios.3,11-16

Eligibility Criteria:
Inclusion Criteria:

* Maternal Age \>18 years
* Oligohydramnios: diagnosed by sonography (defined AFV\<8cm)
* Singleton Pregnancy
* Intact membranes
* Gestational age 24 - 36 weeks

Exclusion Criteria:

* Indication for urgent delivery (severe PET, HELLP syndrome, persistent fetal hypoxemia \[non-reassuring fetal heart rate pattern\])
* Ruptured amniotic membranes; PPROM, PROM, SROM
* Fever (\>38C)
* Multiple gestation
* \>37 week gestation
* Lethal Fetal anomalies and/or demise
* Maternal Cardiovascular disease
* Maternal Renal disease
* Maternal Pulmonary disease (other than asthma)
* Patients using prostaglandin inhibitors, NSAIDs3,15 (within 1 week of enrollment, other than baby asprin)
* Non-English speaking
* Vaginal Infections and/or active skin lesions
* Placenta Previa and/or Unexplained Vaginal Bleeding
* BMI \> 45