Introduction
Oligohydramnios is one of the major causes for Perinatal-Neonatal morbidity and mortality. The cause of Oligohydraminosis multifactorial; however its presence can indicate decrease fetal urine output and renal function.1 Oligohydramnios is independently associated with a high risk of Low birth wt., Intra-uterine growth retardation, need for interventional delivery, pulmonary hypoplasia, renal anomalies and increased risk for Perinatal-Neonatal adverse outcomes.
Oligohydramnios or a reduced volume of amniotic fluid poses a challenge in obstetric management, particularly when it is diagnosed before term. The meaning of oligohydramnios is derived from greek word ‘oligo’ meaning – ‘few’ or ‘scanty’, ‘hydra’ meaning ‘water’ in greek & a latin word ‘amnion’ meaning – ‘membrane around a fetus’.
Amniotic fluid, also known as a ‘liquor amnii’ – a latin word also known as ‘pregnant women’s water’ is the protective liquid contained in the amniotic sac of a pregnant female. This fluid serves as a cushion for the growing fetus, also facilitates the exchange of nutrients, water and biochemical products between mother and fetus.
The incidence of oligohydramnios in the literature varies from 0.5% to 5%, depending on the study population and definition of Oligohydramnios. The incidence of oligohydramnios is reported to be 4% in all pregnancies in USA. The incidence is thought to be higher in developing countries owing to high prevalence of PIH and is more complicated due to lack of ANC services and awareness regarding this problem.
However, Oligohydramnios is often accompanied by other maternal conditions like hypertension, diabetes, PROM, etc. and fetal conditions such as Still birth, Intra-Uterine Growth Retardation, Congenital Malformations, Low birth weight, Perinatal Asphyxia, Renal abnormalities and other conditions.
Substantial number of mothers with decreased amniotic fluid volume Index deliver at our hospital. This study was undertaken with an aim to study the Perinatal-Neonatal outcome in mothers having Severe Oligohydramnios.
Materials and Methods
Inclusion criteria
Neonates born to the Mothers having Oligohydramnios with AFI ≤ 5 by USG and delivered in S.S.G. Hospital, and gestationally matched Non-Oligohydramnios delivery in S.S.G. Hospital.
Exclusion criteria
Included neonates born to Multiple gestation or having no USG proof of Oligohydramnios.
Total 236 newborns satisfying the inclusion criteria were enrolled for the study. A written and informed consent was taken from the parents about enrolment in the study, and sampling procedures was taken and adequate confidentiality was maintained.
The neonates were closely followed from the delivery room and resuscitated as per NRP Protocol and admitted to NICU as per the morbidity. Renal functions were done which included Blood Urea and Serum Creatinine in all the newborns with severe Oligohydramnios after 72 hrs of birth and USG-KUB was done in all the newborns in the study after 72 hrs of life. Repeat Renal functions were done if earlier reports were deranged. Other investigations were done as per their morbidities. Discharge was planned when the baby was out of morbidity and mother was confident enough to look after the feeding and routine care of the baby at home.
Follow up of the babies enrolled in the study was done up to 3 months. The parents were called and for regular follow up. At follow up, apart from the routine advise on feeding, immunization, and counselling on child rearing and the felt needs of the parents, repeat renal functions were done in those babies with deranged Renal function tests, and repeat USG-KUB was done in babies with abnormal USG-KUB during hospital stay. Study tool: All data related to maternal near miss will be collected from maternal near miss sheet of Obstetrics Department (1st February 2020 to 31st July 2020), SPSS version 21, MS excel 2016.
Statistical tests: Descriptive statistics, rate, ratio, mean, Chi-Square test with Fischer-exact test. 100 exposed and 100 non-exposed matched required to get Odd’s ratio 1.68 for perinatal mortality and morbidity with 95% confidence interval and 80% power with one sided test.
Results and Discussion
Total 236 newborns were enrolled in the study, out of these 236, 136 were cases (Mother having severe oligohydramnios) and 100 controls (Newborns born to mother with normal amniotic fluid volume). Final data analysis has been done on 236 newborns, 136 CASES and 100 CONTROLS.
Mean Maternal age of Case (24.92 ±4.65 years) and Control (24.9 ±4.28 years) were comparable. Among cases, there was lower percentage of male birth 43.38%(n=59) as compared to the controls 51%(n=51) among cases, there was higher percentage of female birth 56.62%( n=77) as compared to the controls 49%(n=49). This relation is statistically not significant (p value=0.31) for gender distribution between 2 groups (P=0.3043).
Table 1
Distribution of maternal morbidities between the two groups
Maternal morbidities were comparable in both cases and controls, PIH were slightly higher in cases 21.3%(n=29) as compared to controls 19% (n=19) in our study. It shows there is no statistically no significant difference (p value>0.05). In study by Bansal et al2 PIH was found in 21% of cases, Bangal et al3 16% and Krishna Jagathia et al4 PIH was found to be 21%.
Among cases, there was higher percentage of LSCS as compared to the controls. 56% babies required to be delivered by LSCS. This relation is statistically significant for Mode of delivery distribution between 2 groups (P <0.01 and chi-square value is 5.718).
Similar studies were done showing variable percentage of LSCS, byGolan et al5 (35.2%), Bower Chatoor et al6 (44%), Bansal et al2.,(47%).
Thus different studies have shown different results in incidence of LSCS amongstoligohydramnios, and may depend on the policies adopted by the different hospitals.
Table 2
Comparison of anthropometric profile of the two groups
Mean weight of Cases was significantly lower than Controls. (P = 0.0134). Among cases, there was higher percentage of VLBW and LBW as compared to the controls. This relation is statistically significant for weight distribution between 2 groups (P = 0.0134). Mean weight in our study is 2251 grams, as compared to 2140 grams in study by Bangal et al,7 2748 grams by Jun Zhang et al8 and 56% of newborns born to oligohydramnios were found to be in between 2-2.5 kg by Kondepagu et al.9
Table 3
Distribution of cases as per AFI (Amniotic fluid index)
As per Table 2 in our study we have compared the various parameters like need for LSCS, stillbirth, death, preterm, SGA, congenital malformations, renal dysfunctions – both morphological and functional, & death on follow up with the values of AFI. We found that morphological renal dysfunction to be significantly higher (p value <0.001) for AFI 0 – 1 as compared to higher AFI. Chance of preterm birth was higher among anhydramnios cases as compared to oligohydramnios cases and this difference was statistically significant at 95% CI.
Table 4
OUTCOME Distribution in Case & Control
Still-births were seen in 5.88% of cases, as compared to none in control. In view of 0% in control, statistical analysis was not possible. Still-births in Bangal7 et al study was 8%, and Bansal2 et al study was 5% which were comparable to our study.
Discharge rate was significantly higher in cases as compared to controls (P>0.05).
Death were higher in cases but this is not statistically significant (P>0.05). Death in our study was 2.21%, while perinatal mortality was 7.35%. Similar studies have shown following mortality rates – Casey10 et al 6.4%, Wolff F11 et al 7.2%, Apel-Sarid et al12 9.9%, Chamberlin13 et al 10.9%, Ja Younget14 al 12%, Bangal 7 et al 16%, some of which were comparable to our study.
Table 5
Comparison of various Perinatalmorbidity of oligohydramnios in our study and other studies:
|
Parameters |
Our study |
Bangal VB et al7 |
Jun Zhang et al8 |
Bansal et al2 |
Jayantinath et al 15 |
Shetty et al 16 |
Guin et al 17 |
|
|
Still birth |
5.88 |
8% |
|
5% |
1% |
|
|
|
|
Mode of delivery |
Spontaneous |
43.4 |
56% |
76% |
53% |
17% |
|
57.2% |
|
LSCS |
56.6 |
44% |
24% |
47% |
83% |
|
42.8% |
|
|
Mean Weight |
2251g |
2140 g |
2748g |
|
|
|
|
|
|
SGA |
25% |
|
|
|
|
25% |
14.2% |
|
|
Mortality |
2.21% |
16% |
5.1% |
10% |
2.4% |
3.3% |
12.6% *(perinatal) |
|
|
Congenital malformations |
5.38% |
- |
- |
9% |
- |
5.8% |
4.2% |
|
Conclusion
From this study we concluded that
Among cases, there was higher percentage of female birth as compared to the controls. But the relation is statistically not significant for gender distribution between 2 groups.
Maternal morbidities were comparable in both cases and controls, PIH was slightly higher in cases (21%) as compared to controls (19%).
Among cases, there was higher percentage of LSCS as compared to the controls. 56 % babies required to be delivered by LSCS. This relation is statistically significant for Mode of delivery distribution between 2 groups.
In our study we have compared various parameters like need for LSCS, Stillbirth, Death, Preterm, SGA, Congenital Malformations, and Renal dysfunctions – both Morphological and Functional, & Death on follow up with the values of AFI. We found Morphological renal dysfunction to be significantly higher for AFI 0 – 1 as compared to higher AFI, rest others were comparable.
Both the cases and controls were divided according to the birth weight and most of them fall between 2000- 3000 gms. In our study, weight in cases were significantly lower than those of controls.
Mean weight of Cases was significantly lower than in Controls, among cases, there was higher percentage of VLBW and LBW as compared to the controls. This relation was statistically significant for weight distribution between 2 groups.
We have compared the various parameters like need for LSCS, Stillbirth, Death, Preterm, SGA, Congenital Malformations, and Renal dysfunctions – both Morphological and Functional, & Death on follow up with the values of AFI. We found that Morphological renal dysfunction to be significantly higher for AFI 0 – 1 as compared to higher AFI.
Stillbirths were seen in 5.88% of cases, as compared to none in control. In view of 0% in contact, statistical analysis was not possible. Death were higher in cases but this was not statistically significant. Death in our study was 2.21 %, while perinatal mortality 7.35%. There were more discharged newborns in Controls as compared to Cases, which was statistically significant.
Among cases, there was higher percentage of SGA as compared to the controls. This relation was statistically significant.
All the morbidities-Asphyxia, HIE, HMD, MAS, Sepsis, Meningitis, Jaundice, Hypothermia, Hypoglycemia were observed in both groups and they were not statistically significant.
Congenital malformations were more common in the Cases than in the Controls. Major congenital malformations were seen in 5.14% of cases, as compared to none in control. In view of 0% in control, statistical analysis was not possible.
Between Oligohydramnios with Maternal comorbidities and with isolated oligohydramnios, we compared incidence of LSCS, Stillbirth, Death, SGA, Preterm, Congenital Malformations, Renal Dysfunctions and Death on follow up. There was no significant difference in perinatal outcomes in pregnancies with Isolated Oligohydramnios and Pregnancies with comorbidities & Oligohydramnios.
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