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Open Access Journal of Gynecology Research Article 7 min read

Evidence Based Management of Oligohydramnios

Chauhan NS, Namdeo P and Modi JN*
* Corresponding author
ISSN: 2474-9230  10.23880/oajg-16000160  Received: August 02, 2018  Published: August 20, 2018
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Keywords
Oligohydramnios Amniotic Fluid
Abstract

Background: Oligohydramnios, or abnormally decreased amount of amniotic fluid, complicates approximately 1 to 2 percent of pregnancies. It poses a risk to the fetus by contributing to perinatal morbidity and mortality, and due to iatrogenic preterm delivery. An increase in operative delivery increases the risk to the mother. Oligohydramnios may result from known etiological factors or it may accompany other pregnancy complications. When no etiological factor or association is identified, it is termed “Isolated Oligohydramnios’. Treatment strategies: This review presents the various treatment options for oligohydramnios in the light of current available evidence. Maternal hydration whether orally or by intravenous route is perhaps the most well studied intervention. Many therapeutic agents have also been tried. Of these, L-arginine and sildenafil have been supported by several studies but conclusive evidence for the same could not be identified Conclusions: In cases of isolated oligohydramnios, therapeutic intervention is desirable to prolong the pregnancy so as to avoid preterm delivery and to prevent adverse perinatal outcome. Based on present scientific evidence we recommend that oral hydration therapy should be offered to the eligible women. Use of sildenafil citrate for this purpose cannot be recommended till its safety is well established in view of the recent reports of adverse fetal outcome

Introduction

Oligohydramnios is an abnormally decreased amount of amniotic fluid in pregnancy. It complicates approximately 1 to 2 percent of pregnancies [1]. Sonographically, it is defined as amniotic fluid volume <5 percentile expected for gestational age; Amniotic Fluid Index (AFI) <5 cm or Single Deepest Pocket of liquor (SDP) <2 cm [2, 3].

Evaluation of amniotic fluid provides important information about fetal structural and functional integrity and is predictive of pregnancy outcome. Oligohydramnios can be present as isolated abnormality in an uncomplicated pregnancy, or can be associated with complicated pregnancy. The various possible etiological factors responsible for oligohydramnios are as under [4, 5]:

  • Preterm rupture of membranes
  • Congenital abnormalities
  • Bilateral renal agenesis or cystic dyplasia
  • Obstruction of the urinary tract
  • Meckel-Gruber syndrome
  • VACTERL (vertebral, anal, cardiac, tracheo-esophageal, renal, limb) association
  • Sirenomelia

Sacral agenesis
Intra Uterine Growth Restriction (placental insufficiency)
Post-term pregnancy
Drugs like Angiotensin-converting enzyme inhibitors & Prostaglandin synthase inhibitors
Twin-to-twin transfusion
TRAP (twin reverse arterial perfusion sequence)
Fetal demise
Idiopathic

The risks associated with oligohydramnios depend on the gestation of the pregnancy at which it is diagnosed. Early onset Oligohydramnios is often associated with more serious complications such as compression of fetal organs resulting in birth defects, pulmonary hypoplasia and increased risk of miscarriage or stillbirth. If detected in the latter part of pregnancy, the associated complications could be IUGR, preterm birth, intra uterine fetal demise, intra-partum fetal distress and birth asphyxia. During labor, oligohydramnios can cause cord compression, meconium stained fluid, abnormal fetal heart rate, operative interventions, increased risk of cesarean delivery, lower Apgar scores, intensive care unit admission and neonatal death [6, 7].

Occasionally Oligohydramnios in mid-pregnancy may not have an identifiable etiology and is termed “isolated oligohydramnios” (I0) [8]. The pathophysiology of I0 itself is not clearly understood, but it reflects chronic or late-onset placental insufficiency [9]. In term pregnancies with I0, the baby should be delivered; and in preterm I0 conservative management is advisable to minimize perinatal morbidity due to prematurity [10].

Treatment Strategies for Isolated Oligohydramnios

Oral Hydration Therapy

Rapid oral hydration in women with no other high risk factor has been found to be effective in increasing amniotic fluid volume. Intake of 250 mL of water (or hypotonic solution) in 15 min, total of 2 litres in 2 hours can lead to an increase in fluid volume in both oligohydramnios and normohydramnios, with minimal risks to the mother and the baby. Hydration with water reduces maternal plasma osmolality and increased uteroplacental perfusion. Maternal hydration has advantage over other interventions as it was cheap, easily available, non-invasive and does not require hospitalization or extensive monitoring. However it requires consistent and long term therapy as shown below (Table 1):

| Authors (Year) | Study design (Sample size) | Methodology | Results | Mean Gestational age at diagnosis | Neonatal distress/adverse events | Conclusion |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| Kilpatrick, et al. [11] | Randomized controlled blinded trial, (36) | Hydration group (n = 19) (AFI<6 cm) oral hydration 2000 ml/2-4 h was given. Control Group (n = 19) normal amount of fluid | The mean post-treatment AFI was higher in the Hydration group (6.3 versus 5.1; p < .01) | At term 37±4.8 (Hydration gp): 39±2.4 (Control Gp)s | None reported | Maternal oral hydration increases amniotic fluid volume in women with decreased fluid levels |
| Flack, et al. [12] | Non-randomized intervention study (20) | Study group(n=10) (AFI<or = 5 cm) and Control group(n=10) (AFI > 7 cm) were recruited and AFI determined before and after oral hydration by having the patient drink 2 L of water over 2 hours. | The mean AFI increased from 4.3 to 7.5 cm. No change in AFI was observed in women with normal AFI | 36 weeks (Study group); 35 weeks (Control gp) | None | Short-term maternal oral hydration increases the amniotic fluid index in women with decreased amniotic fluid volume in third trimester |
| Fait, et al. [13] | Prospective, nonrandomized interventional study [60] | IO (AFI<6 cm). Study Group: (n = 30) instructed to drink 2litresof water daily for 1week. Control Group: women with normal AFI (routine hydration) | The mean AFI increased significantly in the Study Group after 1 week (p<0.01). | (Preterm) 29 weeks (Study gp) 28 weeks (Control gp) | Not reported | Long term oral hydration significantly increases the AFIin selected women with reduced fluid. |
| Ghafarnejad, | Randomized | Study group AFI < 6 cm) and | The mean AFI | _ | Not | Acute oral hydration |

controlled trial (44)Control group (AFI > 7cm)increased significantly after intervention in the study groupreportedis a noninvasive, easily accessible and cheap intervention, and an effective way of increasing AFI.

Table 1: Oral Hydration Long Term Therapy.

Intravenous Hydration Therapy

Significant improvements were not reported by isotonic hydration. The mechanism of action was similar to oral hydration i.e improvement in utero-placental perfusion. However, the increase in fluid volume was transitory (Table 2).

  • Several studies on maternal hydration by intravenous fluids over a short duration found an increase in the AFI.
  • Better results were achieved by intravenous hypotonic solution of 2L administered within a single day.
  • Authors
  • Study design (Sample size)
  • Methodology
  • Results (Year)
  • Randomize
  • Treatment group (AFI<6cm) intravenous infusion of (1/2) NS at
  • 1000 mL/h for 2 hrs. Placebo group
  • Yan
  • Rosemb d, double
  • The AFI increased significantly in both blind placebo controlled erg, et al. [15] received an iv infusion of (1/2) NS groups (p <.05) at 10 mL/h for 2 hrs (44)
  • Mean AFI changes was statistically
  • Lorzade
  • Control group: normal hydration, greater in oral water group, in comparison with
  • IV isotonic and IV hypotonic groups
  • Randomize h, et al.
  • Group A: oral 2L/2h. Group B: iv infusion of 2L/2h. NS Group C: iv infusion of 2L/2h hypotonic fluid d clinical trial (80)
  • [16]
  • (p<0.0001).
  • Intravenous group
  • (mean change in
  • AFI 4.5 cm ± 1.25; P
  • Intravenous hydration group
  • (n=25) (AFI <=5cm), 2L/2hrs of
  • Quasi experiment value < 0.05); In
  • Umber
  • 5%D/W. Oral hydration group
  • (n=25) (AFI<=5 cm), 2L/2hrs of oral hydration
  • A [17] al study group (mean change AFI 4.3 ±
  • 1.23, 4.79; P value < (50) water
  • 0.05).
  • IO (AFI<5 cm). Group A: 66 patients with IO Subgroup A1 (n = 33):
  • The mean AFI increased in group
  • Prospectiv
  • 1500 ml iv (Ringer solution) + 1500 ml oral e randomize
  • A after therapy.
  • Patrelli, daily for 6 days.
  • Subgroup A2 (n = 33): et al. d controlled
  • The mean
  • AFI at birth was greater in subgroup
  • [18]
  • 1500 ml iv (Ringer solution) + 2500 ml oral study (137) daily for 6 days. Group
  • B: 71 women with normal AFI
  • A2 in comparison to A1 (P<0.001).
  • (routine hydration)

Table 2: Intravenous Hydration Therapy.

Drugs

Among the pharmaceutical agents, L- arginine is a promising drug for the treatment of oligohydramnios. Nitric oxide synthetized from L-arginine is a potent vasodilator, improves utero-placental perfusion by reducing the viscosity of blood. Several studies have reported an improvement in amniotic fluid volume after L-arginine intake of 3gm as sachet daily for 2-4 weeks. It is noninvasive and does not require monitoring and has an added advantage that its administration does not require hospitalization. However most of these studies have small number of women and no meta-analysis for the same could be identified in literature (Table 3).

  • Authors
  • Study design (Sample size)
  • Methodology
  • Results
  • Gestational age (Year) at diagnosis
  • Patients with AFI < 5th percentile
  • The mean gestational age at
  • Prospective observational for the particular gestational age were prescribed sachets of L-arginine 3g for 1 to
  • The average change in AFI
  • Sreedharan, et al. [19] diagnosis was
  • 31.1±2 weeks study (100) was 2.03±0.39 cm
  • 4weeks.
  • Those who received only l-arginine showed an increase of 1.8 cm in
  • 11 patients (AFI 4-8cm) with gestational hypertension.
  • Were administered L-arginine
  • Prospective interventional
  • Hebbar, et
  • AFI and those who received combined intervention improved
  • (one sachet 3 g, twice daily.
  • Others received both l-arginine
  • 29-35 weeks al. [20] study (50) and intravenous hydration their AFI score by 2.5
  • (500 ml of fructodex 10% cm.
  • The mean AFI at the end of
  • All patients with AFI < 8 cm were
  • The mean gestational age at started on L- arginine 3gm/ 3
  • Soni, et al.
  • Retrospective therapeutic intervention was 8.753, an increase of 3.332 cm times a day, continued till adequate improvement in liquor the time of recruitment was
  • [21] study (100) was noted
  • 32.3 weeks could be obtained

Table 3: Small number of women and no meta-analysis for the same could be identified in literature.

Recently, Sildenafil citrate has emerged as a new drug for the treatment of fetal growth restriction and oligohydramnios. Sildenafil citrate relaxes muscles in the walls of blood vessels and increases blood flow to particular areas of the body notably the pelvic vasculature. Although sildenafil has been used with success in erectile dysfunction in men and also for pulmonary arterial hypertension, only a few studies have reported its success in managing oligohydramnios. This Authors Study design (Sample size) Methodology Results (Year) AFI =4.5cm and fetal weight

550gm.Sildenafil citrate 25 mg vaginally twice a day was Choudhary,

et al. [22] Case report

started at 27 weeks. All medications were continued has been observed at a low dose of 25mg thrice daily. It has been tried more extensively in pregnancies with IUGR. However, recent reports of higher rates of intrauterine fetal demise in pregnancies treated with sildenafil has halted most studies till these losses can be investigated. While the studies and dosages used are enlisted in Table 4, it cannot be recommended for use until cleared (Table 4).

Gestationa

Neonatal distress/ adverse effects

l at diagnosis Conclusion

In this case of early- onset FGR, sildenafil Ultrasound at 30 weeks showed an AFI of 7.5 and

27 weeks None

citrate therapy was a fetal weight of 1,000 g.

successful in managing FGR and

  • with weekly monitoring of fetal weight and AFI. women with severe early onset fetal growth restriction and oligohydramnios were treated with with Sildenafil
  • Prospective intervention
  • Premlatha, et al. [23] al
  • Study(100) citrate 25 mg three times a day
  • IO with AFI<5cm were recruited. Sildenafil group(n=82) 25 mg every 8
  • Maher, et open-label randomized al. [24] hours) plus intravenous infusion of 2 L isotonic sol. trial (184)
  • Hydration group (n=84) receiced only fluid therpy
  • Pregnant women who were
  • Dunn, et al.
  • Systematic exposed to Sildenafil citrate(SC) compared to no
  • [25] review
  • SC or placebo. disorders.
  • Recent warning:
  • Newspaper https://www.usatoday.com/story/news/nation-now/2018/07/25/viagra-pregnant-moms-stopped-after-babiesdie/832457002/ https://www.theguardian.com/australia-news/2018/jul/25/queensland-trial-giving-viagra-to-pregnant-women-haltedreporting link:

Table 4: Studies and Dosages.

Timing of Delivery

Timing of delivery in patients with isolated oligohydramnios is controversial. Observational studies have reported that prolonging the pregnancy till 37 completed weeks in patients with isolated mild oligohydramnios and no other comorbid condition, resulted in a good perinatal outcome. However pregnancies which were remote from term should be managed conservatively and should be kept under regular follow up with frequent assessment of AFI. Pregnancies with moderate to severe oligohydramnios may be delivered at 35 completed weeks after administration of antenatal steroids. Emergency delivery may have to be done anytime that fetal compromise is suggested on fetal surveillance by cardiotocograph or on Doppler [1].

Conclusion

In cases of isolated oligohydramnios, therapeutic intervention is desirable to prolong the pregnancy so as to avoid preterm delivery and to prevent preinitial consequences of operative delivery. We recommend that oral hydration therapy should be offered to the eligible women as it is safe, inexpensive, does not require admission and no side effects have been reported so far. Sildenafil citrate holds promise but should be used with caution in pregnancy as no large controlled trials have been done to prove its efficacy. Further studies that show more definitive results, along with an establishment of safety, have to be assessed before the drug can be prescribed for this condition.

The amniotic fluid
olume was higher in
hesildenafilgroup a
the final assessment

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@article{chauhan2018,
  title   = {Evidence Based Management of Oligohydramnios},
  author  = {Chauhan NS, Namdeo P and Modi JN},
  journal = {Open Access Journal of Gynecology},
  year    = {2018},
  volume  = {3},
  number  = {3},
  doi     = {10.23880/oajg-16000160}
}
Chauhan NS, Namdeo P and Modi JN (2018). Evidence Based Management of Oligohydramnios. Open Access Journal of Gynecology, 3(3). https://doi.org/10.23880/oajg-16000160
TY  - JOUR
TI  - Evidence Based Management of Oligohydramnios
AU  - Chauhan NS, Namdeo P and Modi JN
JO  - Open Access Journal of Gynecology
PY  - 2018
VL  - 3
IS  - 3
DO  - 10.23880/oajg-16000160
ER  -