European Journal of Cardiovascular Medicine

Just as our early ancestors moved from aquatic environments to terrestrial ones, we, similarly, reside in amniotic fluid until we are born. This safeguarding liquid, referred to as amniotic fluid or "liquor amnii" in Latin, envelops the fetus within the amniotic sac and starts to develop approximately 7 to 8 days after fertilization. It comes from a mix of maternal plasma that passes through the placenta, secretions from the amniotic epithelium, and contributions from the fetal skin, kidneys, and lungs. The fluid is mildly alkaline with a specific gravity ranging from 1.008 to 1.010 and has an osmolality of 260 mOsmol/litre. Although it is hypotonic compared to both maternal and fetal plasma, it remains isotonic with fetal urine. Initially clear, the fluid begins to take on a pale straw color close to term due to the presence of shed lanugo and fetal skin cells. The volume of amniotic fluid grows as pregnancy progresses but declines significantly around the estimated time of delivery. 1-5

The amniotic fluid is vital for fetal growth, aiding in the maturation of the lungs and gastrointestinal system through activities like fetal breathing and swallowing. It also enables fetal movement, which is important for the development of the neuromusculoskeletal system, provides protection against compression of the umbilical cord and physical injury, and possesses bacteriostatic qualities. Furthermore, amniotic fluid serves as a medium for extracellular signaling molecules and stem cells during the process of embryonic development. Irregular amounts of amniotic fluid can signify problems with the fetus or placenta, indicating possible issues with the production or circulation of the fluid. Extreme variations in volume are associated with negative outcomes in pregnancy.6-8

The amniotic fluid index (AFI) is determined by adding the largest vertical measurements of fluid pockets in each quadrant through the four-quadrant ultrasound method, which is useful for evaluating fetal health. Oligohydramnios, identified by an AFI of 5 cm or less, was originally defined by a largest pocket measurement of less than 1 cm but was later changed to a single pocket measurement of 2 cm in both vertical and horizontal orientations. Research, including studies by Jeng et al., has proposed an AFI threshold of 8 cm due to its link with heightened risks of meconium staining, fetal distress, cesarean delivery, irregular heart rate patterns, and diminished Apgar scores.9,10

Oligohydramnios occurs in approximately 1-5% of pregnancies and can result in complications in around 12% of cases that go beyond 41 weeks. It is linked to conditions such as utero-placental insufficiency (e.g., fetal growth restriction, hypertension, preeclampsia, or diabetes with vascular complications), ruptured amniotic membranes, and pregnancies that extend past term. The risks for the mother include a higher chance of needing labor induction, operative vaginal deliveries, and cesarean sections because of fetal distress. Fetal complications associated with oligohydramnios can include growth restriction, meconium aspiration syndrome, birth asphyxia, low Apgar scores, congenital anomalies, stillbirth, irregular fetal heart rate patterns, and acidosis. Long-term consequences may involve pulmonary hypoplasia, Potter’s syndrome, and limb or hip deformities.11,12

Polyhydramnios, which occurs in 0.2 to 1.6% of pregnancies, is frequently attributed to gestational diabetes, fetal abnormalities that impact fluid swallowing (such as cleft palate or esophageal/duodenal atresia), infections, and other less common causes. Maternal symptoms may consist of shortness of breath, premature rupture of membranes, pre-term labor, unusual fetal positions, cord prolapse, and postpartum hemorrhage. Given that gestational diabetes is a common contributing factor, it is often associated with fetal macrosomia. Potential complications for the fetus include respiratory distress syndrome and being born prematurely.13-15

Objectives:

1. To study incidence of oligohydramnios and polyhydramnios in pregnant women attending OPD and IPD.
2. To study obstetric outcome in pregnancies with oligohydramnios and polyhydramnios.
3. To determine the perinatal outcome in pregnancies complicated with Oligohydramnios and polyhydramnios.

Study Design: A prospective observational study.  

Study area: mother and child hospital, Yadgir institute of medical sciences, Yadgir. 

Study Period: 1 year.

Study population: Pregnant women with abnormal AFI reporting to mother and child hospital, Yadgir institute of medical sciences, Yadgir during study period.

Sample size: The study consisted of a total of 450 subjects. 

Sampling method: convenience sampling method.  

Inclusion criteria:

•          Pregnant women with gestational age between 28 to 42 weeks with intact membranes.

•          AFI</-5cm and AFI>/-25cm as determined by ultrasonography.

•          Singleton pregnancy.

Exclusion criteria:

• Premature rupture of membranes

• Post term pregnancies

• Congenital anomalies of the fetus

• Multiple gestation

Ethical consideration: Institutional Ethical committee permission was taken before the commencement of the study.

Study tools and Data collection procedure:

Data is collected using prevalidated proforma meeting the objectives of the study by convenience sampling method. The patients of gestational age 28-42 weeks who will be diagnosed to as oligohydramnios (AFI</-5cm) and polyhydramnios (AFI>/-25cm) as per standard definition by Moore TR, 1997 will be included in the study.  Detailed history like duration of amenorrhea, fetal movements, past obstetrics history, medical history regarding hypertension, diabetes and renal disease will be recorded. On clinical examination presence of anaemia, pedal edema, blood pressure will be recorded. Routine examination of cardiovascular system and respiratory system will be made.

On per abdomen examination the following points are noted:

• Symphysio-fundal height

• Presentation and position of the fetus

• Fetal heart sound

• Amount of liquor- normal, decreased or increased clinically

All cases are subjected to routine blood investigations like blood grouping, Rh typing, HIV, HbsAg, VDRL, OGTT, urine routine and microscopy. Detailed ultrasound examination using linear array real time B scan is done and AFI is measured using Phelan’s four quadrant ultrasound technique. Examination was performed with patients in supine position. External landmarks of maternal abdomen were used to divide the gravid uterus into four quadrants. Umbilicus was used to divide it into right and left halves. The linear transducer head was placed along mother’s longitudinal axis and held perpendicular to the floor. The maximum vertical diameter of the largest fluid pocket was measured in centimetres in each of the four quadrants. Vertical was defined as perpendicular to the transducer head. Brief appearance of cord or an extremity was ignored. When the pocket was almost entirely filled with either cord or fetal extremity it was not included. The measurements obtained from each quadrant were summed up to obtain the amniotic fluid index. 6 to 8 antenatal visits along with 4 weekly scan will be done for cases with abnormal liquor till delivery. A NST was done in all patients on admission. Per vaginal examination is done to note Bishop’s score and adequacy of pelvis for women beyond 37weeks of gestational age. Variables measured are incidence of non-reactive NST, caesarean delivery for fetal distress, Apgar score, birth weight, meconium staining of liquor, admission to NICU and neonatal deaths. Chisquare statistical test was applied to find out if there is any association between the AFI level and variables studied. Odds ratio was used to assess the strength of association. The AFI level 8.1-25 has considered as reference category. All the other three levels have been considered and expressed with 95% CL (confidence limit) of odds ratio.

In this study, 450 antenatal cases of term gestation were included, among that 80 antenatal cases with abnormal AFI were studied. The study was divided into 3 categories based on AFI and the correlation between amniotic fluid index and variables studied like NST, mode of delivery, colour of liquor, Apgar score, birth weight, IUGR, NICU admission of babies and neonatal death. 

Table 1: AGE-GROUP DISTRIBUTION OF THE PATIENTS

A total 80 subjects were considered for the study, the mean age of the cases were 27.27 years with SD 5.15, IQR: 18-40 Years, median 28 years. Age group between 26- 30years (30%) are more predominant followed by 18-25 years (36.25%), 31-35years was 18.75% and least was found in >36 was 7.50%. The difference in the proportion of age groups between the AFI was found to be insignificant with a “p” value of 0.058.

TABLE 2: DISTRIBUTION OF GRAVIDA

In the study, majority of the subjects were multigravida (61.25%) and primigravida were 38.75%. The difference in parity and between the AFI was found to be insignificant, with a “p” value of 0.510.

TABLE 3: DISTRIBUTION OF GESTATIONAL AGE

In this study, majority of subjects were >37weeks of gestation (67.5%) while remaining subjects were <37weeks of gestation. The difference in the proportion of onset of labor between the AFI was found to be significant with a “p” value of <0.001.

TABLE 4: DISTRUBUTION OF AFI

This table shows the distribution of AFI in the study group. In the study, majority of the subjects had AFI 3 to 5cm (58.75%) and next majority was >25cm (33.75%). 7.5% had AFI <3cm. In 450 subjects included in the study 53 had AFI less than 5cm and 27 had AFI more than 25cm. Incidence of oligohydramnios in the is 11.7% and that of polyhydramnios is 6%.

TABLE 5: CORRELATION OF CTG

In the study, CTG was reactive in most subjects (83.75%) and non-reactive in others (16.25%). It was found to be statistically significant p<0.01 Chi-square-3.69 odds ratio: 1.28.

TABLE 6: - CORRELATION OF ONSET OF LABOUR

In the study, spontaneous onset of labour was in 52.5% subjects, 23.75% subjects had PGE2 Gel induction and 23.75% subjects underwent LSCS. It was found to be statistically significant p Chi-square- 3.77 odds: 1.22.

TABLE 7: INDICATION FOR C-SECTION

                   Chi-square- 4.87              odds: 2.99

In the study, majority of subjects underwent C-section due to previous C-section (25.53%), next majority due to foetal distress (23.40).

TABLE 8: COLOUR OF LIQUOR

                  Chi-square- 6.33 odds: 3.14

In the study, majority of the subjects had clear liquor (88.75%) and remaining had meconium-stained liquor (11.25%). It was found to be statistically significant at 5% level.

TABLE 9: MODE OF DELIVERY

                                               Chi-square- 3.66 odds: 1.71

In the study, majority of subjects underwent C-section (57.5%), 36.25% had normal vaginal delivery and 6.25% had vacuum assisted vaginal delivery. All are found to be statistically significant at 5% level of significance Chi-square- 3.66 odds: 1.71

TABLE 10: DISTRIBUTION OF BIRTH WEIGHT

In the study, 62.5% babies had birth weight of >2.5kgs and 37.5% had birth weight of <2.5kgs. > 2.50 kgs are found to statistically significant the tested chi-square value was Chi-square- 4.17 odds: 3.10.

TABLE 11: DISTRIBUTION OF APGAR SCORE AT 5 MINUTES

In the study, 86.25% babies had APGAR score at 5 minutes of >7 and 13.75% had APGAR score of <7. >7 score was statistically significant and <7 was insignificant, tested by unpaired t test t value was 2.36, Chi-square- 4.18 odds: 2.88.

Table 12: NICU ADMISSION STATUS

In the study, majority babies had NICU admission (60%) and remaining 40% babies didn’t have NICU admission. Both were found to significant with Chi-square- 4.69 odds: 1.86.

The determination of amniotic fluid volume using the Amniotic Fluid Index (AFI) is now a standard practice in fetal biological profile scoring. The correlation between abnormal AFI values and adverse maternal and perinatal outcomes is well-established. This descriptive follow-up study was conducted to examine the relationship between AFI and feto-maternal outcomes.

Maternal Age: In India, the reproductive age is generally considered to be between 20 and 25 years. However, our study found that the majority of participants were aged 26 to 30 years, with a mean age of 27.7 years. This is consistent with the findings of Suvarna V et al., Gita G et al.,16,17 Ahmar R et al.,18 and Kaur T et al.,19 who reported similar mean maternal ages.

Parity: Primigravida women accounted for 38.75% of the study group, while multigravida women represented 61.25%. These figures are comparable to those reported by Gita G et al.20 and Jayati Nath, where multigravida cases were predominant.21

Gestational Age: Our study observed that 67.50% of women were beyond 37 weeks of gestation, while 32.50% were less than 37 weeks. An unpaired t-test revealed no significant association between gestational age and AFI, aligning with findings from Tiparse et al. (2017).22

Cardiotocography (CTG): CTG monitors various fetal parameters, including baseline heart rate, beat-to-beat variability, accelerations, and decelerations. Beat-to-beat variability is the most sensitive indicator. ACOG guidelines suggest that continuous electronic fetal monitoring often results in high false-positive rates and unnecessary interventions. It is recommended for use only in high-risk pregnancies. CTG measures uterine activity with an external tocodynamometer and fetal heart rate with a Doppler ultrasound transducer.

In our study, 83.75% of CTGs were reactive, while 16.25% were non-reactive. This difference was statistically insignificant (Chi-square: 3.69, Odds Ratio: 1.28).

Mode of Delivery: The modes of delivery in our study were spontaneous (52.50%), gel induction, and LSCS (23.75%). These results are similar to those reported by Gita G et al. and Sushma M et al., where caesarean sections were common due to fetal distress.20,23

Indications for Caesarean Section: The primary indications for caesarean delivery were previous LSCS (25.53%), fetal distress (23.40%), and failure to progress (14.89%). Other reasons included mobile head/CPD and malpresentation (8.51%) and anhydramnios (10.64%). Fetal distress as an indication for caesarean section is consistent with Sushma M et al.'s findings.23

Colour of Liquor: Meconium staining was observed in 11.25% of cases. Aneela et al. (2009) reported a similar incidence of 8.5% in women with AFI <5 cm. Baron et al. and Kwon found no significant difference in meconium staining between women with borderline oligohydramnios and those with normal amniotic fluid volumes.24,25

Birth Weight: In our study, 62.5% of infants weighed more than 2.5 kg, while 37.5% weighed less than 2.5 kg.

Apgar score: The Apgar score assesses neonatal well-being and helps identify babies who may need resuscitation. It includes five components: heart rate, respiratory effort, muscle tone, reflex irritability, and color, with each component scored up to 2 points. In our study, 13.75% of infants had an Apgar score below 7, comparable to the 16% reported by Chate P et al.26

NICU Admission Status: 60% of infants were admitted to the NICU, a statistically significant finding consistent with results from Chandra et al. (46.15%) and Chate P et al. (42%).26,27

Mortality: No neonatal or perinatal mortality was observed in our study, similar to findings from Hasina Akhtar and Sadia Sultana.28,29

Isolated oligohydramnios or polyhydramnios at term often has better outcomes but requires thorough evaluation, including ultrasound and clinical assessment, to detect anomalies or underlying causes. Early detection and management improve fetal outcomes and reduce maternal complications.

1.       Bottom S F et al – Limitation of using maximum vertical pocket & other sonographic evaluation of amniotic fluid volume of predict fetal growth; technical or physiologic. Am.J.Obstet & Gynaecol 1986;155;154-8.

2.       Brace & Wolf – Charaterisation of normal gestational changes in amniotic fluid volume. Am.J.Obstet & Gynaecol 1986:161;882-8.

3.       Chamberlain P.F., Manning FA – US evaluation of amniotic fluid volume Am.J.Obstet & Gynaecol 1984;150;245-249.

4.       Chauhan SP et al – Perinatal outcome & AFI in antepartum & intrapartum periods a meta-analysis. Am.J.Gynaecol 1999:1473-8.

5.       Christoper.C. Crooms.S., Banias.B., Do semiquantitative amniotic fluid index reflect actual volume of amniotic fluid Am.J.Obstet & Gynaecol 167;995-9;1992.

6.       Freeman, Leecy, Diloreto PC, O.cane JM – A study of fetal heart rate acceleration pattern Obst & gynaec 45;145;1975.

7.       Gramel S H et al – Oligohydramnios & appropriately grown fetus. Am.J.Perinatology. 1997:14:359-63.

8.       Grant A, ElbournsD Valentine L Routine fetal movement counting and risk of antepartum late death in normally formed singleton lancet 2;345;1989.

9.       Hoskins IA, Freeden FJ, Young – Variable decleration in reactive NST with decreased AFI predict fetal compromise. Am. J. Obstet & Gynaecol 165;1094;1991.

10.    Kreiser D et al – Decreased AFI in low risk pregnancy.J of Reproductive Medicine 2001;46:743-6.

11.    Moore T.R.Cayle JE; Amniotic fluid index in normal human pregnancy Am.J. Obstet & Gynaecol 162;168;1990.

12.    Perez, Delboy A Weiss J – A randomized trial of vast for AN fetal testing Am.J.Obstet & Gynaecol 187;146;2002.

13.    Phelan J.P et al – amniotic fluid volume assessment using four quadrant technique J.Rep.Med.32;540;1987.

14.    Platt LD, paul RH phelan J et al – 15yrs of experience with AN fetal testing Am.j.Obst & Gynaec 156; 1509;1987.

15.    Rayburn WF clinical significance of perceptible fetal motion Am.J. Obst & Gynaec 138;210;1980.

16.    Suvarna V, Reddy MN. The impact of intrapartum amniotic fluid index on perinatal outcome. IAIM. 2018; 5(9): 74-82. 19.

17.    Chauhan SP, Cowan BD, Magann EF, Roberts WE, Morrison JC, Martin JN. Intrapartum amniotic fluid index: A poor diagnostic test for adverse perinatal outcome. J Reprod Med Obstet Gynecol. 1996; 41(11): 860-6.

18.    Ahmar R, Parween S, Kumari S, Kumar M. Neonatal and maternal outcome in oligohydramnios: a prospective study. Int J Contemp Pediatr. 2018; 5:1409-13.

19.    Tajinder K, Ruchika S. Feto-maternal outcome in pregnancies with abnormal AFI. IOSR-JDMS. 2016;15(4):71-5.

20.    Gita G, Shweta P, Arvind L, Shashi K. A prospective clinical study of feto-maternal outcome in pregnancies with abnormal liquor volume. J Obstet Gynecol India. 2011; 61(6): 652-5.

21.    Jayati Nath, Maneesha Jain, Rehana Najam. A Clinical study on oligohydramnios in the third trimester of pregnancy with special emphasis on the perinatal outcome.Journal of Evolution of Medical and Dental Sciences 2013;39:7386-91

22.    Tiparse A et al. Int J Res Med Sci. 2017 Aug;5(8):3292-3298 Ultrasound evaluation of pregnancies with oligohydramnios in third trimester and their feto maternal outcome at tertiary care hospital.

23.    Sushma DM, Sukhavasi DS. Study of low amniotic fluid index as a predictor of adverse perinatal outcome. Int J Clin Obstet Gynaecol. 2020; 4(3): 234-7.

24.    Kwon JY, Kwon HS, Kim YH, Park YW. Abnormal Doppler velocimetry is related to adverse perinatal outcome for borderline amniotic fluid index during third trimester. J Obstet Gynaecol Res. 2006;32(6):545-9.

25.    Mahapatrol AK, Jena SK, Ghose S. Pregnancy outcome following induction of labour in oligohydramnios and borderline liquor at term: A comparative study. J Evol Med Dent Sci. 2013; 52:10289-94.

26.    Chate P, Khatri M, Hariharan C. Pregnancy outcome after diagnosis of oligohydramnios at term. Int J Reprod Contraception Obstet Gynecol. 2013; 2(1): 23-6.

27.    Chandra P, Kaur SP, Hans DK, et al. The impact of amniotic fluid volume assessed intrapartum on perinatal outcome. Obs Gynaecol. 2000; 5(8):178-81.

28.    Akhter H, Guha K, Daisy KP. Amniotic fluhid index in high risk pregnancies and pregnancy outcome. Dinajpur Med Col J. 2010;3(1):1-5.

29.    Sultana S, Khan MNA, Akhtar KAK, Aslam M. Low amniotic fluid index in high-risk pregnancy and poor APGAR score at birth. J Coll Phys Surg Pak. 2008;18(10):630-4.