Introduction
Oligohydramnios is considered as a potential sign of fetal compromise and is associated with increased perinatal morbidity and mortality. Amniotic fluid is needed for maintaining fetal well-being; therefore, oligohydramnios can impact on outcome of pregnancy.
It is universally accepted now that an adequate amniotic fluid volume is an essential requirement for apposite intrauterine development and better outcome during neonatal phase.1, 2 Amniotic fluid helps in development of fetal lungs, musculoskeletal and gastrointestinal systems normally and prevents umbilical cord compression. The liquor amnii rises from 25ml at 10 weeks to around 400-500ml at 20 weeks. This volume increases at 28 weeks to approximately 800-1000ml. Liquor amnii plateaus at around term and decreases further to reach 400ml at 42 weeks.3
Oligohydramnios is reduction in volume of amniotic fluid to less than 5cm which affects 3-5% of pregnancies. Amniotic fluid index helps to measure amniotic fluid semi-quantitatively. It is a better and more objective method to estimate amniotic fluid volume as it measures fluid in all 4 quadrants. Amniotic fluid index of 5-18cm is taken as normal. Oligohydramnios in last trimester often leads to non-reassuring fetal heart, need for induction of labor, meconium aspiration syndrome and increased incidence of still birth and perinatal death.4 It is also associated with malpresentations and umbilical cord compression.
Since maternal dehydration increases chances of oligohydramnios, simple oral hydration of pregnant women has been suggested to increase amniotic fluid volume. In literature, maternal hydration therapy is known to restore amniotic fluid volume and therefore, reducing incident of perinatal morbidity and mortality. Sherer et al. in 19905 confirmed that there is significant increase in amniotic fluid after giving oral hydration therapy in patient with oligohydramnios. This study is conducted for assessment of effect of maternal oral hydration on amniotic fluid index in cases diagnosed as isolated oligohydramnios in third trimester of pregnancy and its influence on perinatal outcome. Hydration of patients with oligohydramnios in 3rd trimester of pregnancy caused increase in amniotic fluid volume with mean change of approximately 4.5cm.6
Materials and Methods
The study is prospective, randomized, comparative study conducted at Department of Obstetrics and Gynecology, MGM Hospital, Navi Mumbai. Written, valid and informed consent was obtained from all women who participated in the study. Pregnant women of more than 28 weeks of gestation with moderate oligohydramnios of amniotic fluid index between 5-8 cm.
A total of 50 pregnant women were included in the study after taking informed consent. The patients were divided into two groups (25 each). Sample size was not based on any statistical calculations and assumptions and it is planned to use 25 samples for each of the two groups. Thus, a total of 50 patients were included in the study with 25 in study group and 25 in control group.
Study group
25 pregnant women with moderate oligohydramnios from study group were given 2 litres of water in 2 hours for 7 days apart from their routine water intake and ultrasound was done after 2 hours after completion of water intake, 24 hours and then after 7 days.
Control group
25 pregnant women with moderate oligohydramnios from control group were give routine medications as per the Institute protocol and was explained to have routine water intake. Ultrasound was done after 2 hours after registering the case as control, 24 hours and 7 days.
All pregnant women with singleton pregnancy of gestational age more than 28 weeks with cephalic presentation with amniotic fluid index of 5-8 cm were included in study. Gestational age of less than 28 weeks, Multiple pregnancy, Post term pregnancy, Heart disease in pregnancy, Renal disease in pregnancy, Pregnancy induced hypertension and Gestational Diabetes, Abruptio placenta, Placenta previa, Preterm rupture of membranes, Ultrasound suggestive of anomalous fetus and patients in labor with ruptured amniotic membranes were excluded from study.
Detailed analysis was carried out with respect to:
Results
Study hypothesis
Null hypothesis (H0): Oral rehydration therapy does not have any effect on the AFI after 7 days.
Alternate hypothesis (H1): Oral rehydration therapy improves the AFI after 7 days.
Data expression
Measurement data for gestational age (GA), birthweight and scores for AFI and APGAR are expressed as means with median and standard deviation (SD). Change in AFI at 2 hours, 24 hours and 7 days are calculated and expressed as means with median and SD. Discrete and nominal data is presented as numbers with percentages. 95% confidence intervals are presented as appropriate.
Data analysis
Baseline GA at enrollment, GA at delivery and birth weight is compared for differences using unpaired sample t-test.
The AFI scores are compared between the two groups at baseline (pre-treatment), 2 hours, 24 hours and 7 days using the Mann-Whitney ‘U’ test. Similarly, the change in AFI scores from baseline after 2 hours, 24 hours and 7 days are compared between the two groups using the Mann-Whitney ‘U’ test.
Within group changes in AFI scores are analysed using the Freidman test with time as independent variable.
The improvement in AFI (improved, not improved) is compared between the two groups after 2 hours, 24 hours and 7 days using Fischer’s chi-square test. Similarly, the need for NICU admission and need for LSCS is compared between the two groups after 2 hours, 24 hours and 7 days using Fischer’s chi-square test. The mode of delivery is compared between the two groups using chi-square test. Odds ratio are calculated for number of patients with improved AFI score at 2 hours, 24 hours and 7 days.
The APGAR scores at 1 hour and 5 hours is compared between the two groups using the Mann-Whitney ‘U’ test.
All testing was done using two-sided tests at alpha 0.05. Thus, the criteria for rejecting the null hypothesis was be a ‘p’ value of <0.05.
Table 1
Age (yrs.) and gestational age (wks.)
Table 2
Parity
|
|
Study (n=25) |
Control (n=25) |
Chi-square test |
|||
|
|
No. |
% |
No. |
% |
c2 |
p |
|
Primi |
13 |
52.0% |
15 |
60.0% |
0.569 |
0.776 |
|
Multi |
12 |
48.0% |
10 |
40.0% |
|
|
Table 3
AFI score (ultrasound)
Table 4
Improvement in AFI score from pre-treatment
Table 5
Amnioticfluid status after 7 days
|
Study (n=25) |
Control (n=25) |
|
||||
|
No. |
% |
No. |
% |
O.R. |
||
|
No oligohydramnios |
17 |
68.0% |
0 |
0.0% |
25.769 |
<0.0001 |
|
Moderate oligohydramnios |
3 |
12.0% |
10 |
40.0% |
||
|
Severe oligohydramnios |
5 |
20.0% |
15 |
60.0% |
||
Table 6
Odds ratio for improvement in AFI score
Table 7
Delivery type
|
|
Study (n=25) |
Control (n=25) |
Chi-square test |
|||
|
|
No. |
% |
No. |
% |
c2 |
p |
|
FTND |
18 |
72.0% |
8 |
32.0% |
8.754 |
0.013 |
|
LSCS |
4 |
16.0% |
13 |
52.0% |
|
|
|
Outlet |
3 |
12.0% |
4 |
16.0% |
|
|
Table 8
LSCS
|
|
Study (n=25) |
Control (n=25) |
Chi-square test |
|||
|
|
No. |
% |
No. |
% |
c2 |
p |
|
No LSCS |
21 |
84.0% |
12 |
48.0% |
9.273 |
0.026 |
|
FD |
4 |
16.0% |
7 |
28.0% |
|
|
|
MSAF |
0 |
0.0% |
4 |
16.0% |
|
|
|
FI |
0 |
0.0% |
2 |
8.0% |
|
|
Table 9
Neonatal parameters
Discussion
Improvement in amniotic fluid index after 2 hours of hydration therapy
The mean pre-treatment AFI at baseline was comparable between both groups.
There was no significant improvement in 14 pregnant women in both groups in AFI two hours after the hydration therapy in both study and control groups. Improvement was seen in 5 pregnant women in study group and 2 pregnant women in control group after 2 hours of hydration therapy. While AFI reduced further in 6 pregnant women in study group and 9 in control group after two hours. The difference was however, statistically non-significant (p>0.05).
Improvement in amniotic fluid index after 24 hours of hydration therapy
In our study, no improvement in amniotic fluid index after 24 hours of hydration therapy was seen in 8 pregnant women in study group and 6 pregnant women in control group. Amniotic fluid index increased in 13 pregnant women in study group while only 2 pregnant women showed improvement in amniotic fluid index from the control group. Reduction of amniotic fluid index was seen in 4 and 17 from cases and control groups respectively. The difference was statistically significant (p<0.05).
Improvement in amniotic fluid index after 7 days of hydration therapy
Amniotic fluid index improved in 19 cases as compared to pretreatment levels in study group. Amniotic fluid index worsened in 21 pregnant women from control group. The difference was statistically significant (p<0.05).
In this study, there is significant rise in AFI after oral hydration of pregnant women (p<0.05).
In a study by Ghafarnejad7 reported that with maternal oral hydration, mean AFI improved from 50.8 to 67.8mm (p<0.001) which correlated with our present study.
Fait et al8 published similar results and document that short term increase in AFI continues in long term if maternal hydration is continued by drinking 2 litres of water every day for 1 week which is similar to results in present study where mean AFI has increased up to 7.72 +/- 2.64 cm after 7 days of hydration.
Comparison to type of delivery
In our study, 72% cases from study group had full term vaginal delivery with 12% instrumental delivery and only 16% caesarean delivery which were done in view of fetal distress.
However, 52% cases underwent caesarean delivery and 32% had full term vaginal delivery in control group. This difference is statistically non-significant (p>0.05).
In control group, caesarean delivery was done for fetal distress in 7 cases (28%), 4 cases (16%) for meconium stained amniotic fluid and 2 cases (8%) in view of failure of induction.
In a study by Brain S Cater et al9 documented 20-30% increase in AFI and a reduction in rate of caesarean section after oral maternal hydration with pregnancies with isolated oligohydramnios which correlates with our study.
In a study by Mahnaz Shahnazi et al10 reported significant rise in amniotic fluid index in group which was hydrated from 4.7 to 6.25 cm. Meconium stained liquor was seen in 20% cases and 36% in control group which was statistically non-significant.
Neonatal parameters
In our study, the mean birth weight and APGAR score at 1 minute among the newborns was compared in both groups.
The mean birth weight in study group was 2.78kg +/- 0.34 and 2.29kg +/- 0.57 in control group. This difference was statistically significant (p<0.05).
In study group, the mean APGAR score at 1 minute was 6.52 +/-0.71 and in control group it was 5.72 +/- 0.84. This difference was statistically significant (p<0.05).
In a randomized control trial by Akter MD et al, 11 fetal outcome was healthy in 87.1% in study group and 59.4% in control group, asphyxiated in 12.9% in study group and 50% in control group and perinatal death was 3.22% in intervention group and 21.8% in control group.
The study group cases in which AFI has increased to 7 or above has increased rate of vaginal delivery and better APGAR score at birth. Similar results were documented by Golan et al.12 and Charu et al.13
NICU admission
In our study, 2 babies were admitted in NICU in view of low birth weight. While in control group, 12 cases (48%) had NICU admission. 3 cases (12%) for low birth weight, 5 cases (20%) due to respiratory distress and 4 cases (16%) were taken to NICU for observation due to minor ailments. However, there were no intrapartum deaths in this study but one baby expired in the first week of life due to grade 4 respiratory distress.
Bangal VB et al14 documented still births of 8% and 16% neonatal deaths in a study on perinatal outcome in 100 cases of oligohydramnios.
Conclusion
Oral maternal hydration therapy with water improves the level of amniotic fluid index significantly in third trimester of pregnancy. Hydration with water is not associated with any adverse maternal outcomes.
It is associated with similar perinatal outcomes as it is observed in patients with normal amniotic fluid index in third trimester. Maternal hydration therapy orally is simple, easy, non-invasive and probably a very effective way to increase the liquor in cases of isolated oligohydramnios.
Although a continuous hydration therapy for a long term will help to improve the perinatal and neonatal outcome.
Our data presents that pregnancy with isolated oligohydramnios, oral hydration therapy significantly increases the amount of amniotic fluid.
