European Journal of Cardiovascular Medicine

Amniotic fluid is the faintly alkaline fluid contained by the amniochorionic membranes that surrounds the fetus after first few weeks of gestation allowing it to float in the fluid until birth. The fluid helps protect and cushion the fetus and plays an important role in the development of many fetal organs including the lungs, kidney and gastrointestinal tract. Oligohydramnios is a state of decreased amniotic fluid relative to gestational age. Phelan et al. originally defined it as amniotic fluid index (AFI) of ≤5 cm.(1) The amniotic fluid volume when less than the 5th percentile or 2 standard deviation below the normal for that gestation is a specific criteria for oligohydramnios.(2) Oligohydramnios is a common complication of pregnancy and the incidence of this is reported to be around 1 to 5 % of total pregnancies.(3)

Decreased amount of amniotic fluid, particularly in third trimester, has been associated with multiple fetal risks like cord compression, musculoskeletal abnormalities, intrauterine growth restriction, low birth weight, fetal distress in labour, meconium aspiration syndrome, severe birth asphyxia, low APGAR scores, NICU admission, congenital abnormalities and stillbirths.(4)

Aims and Objectives: To study maternal and perinatal outcome in oligohydramnios in term patients in a tertiary care hospital.

It was an Observational, Prospective and clinical study of 200 patients diagnosed with oligohydramnios by ultrasound, conducted in the Post Graduate Department of Gynaecology and Obstetrics, S.M.G.S Hospital, GMC Jammu over a period of 6 month i.e. January 2024 to June 2024. The study was conducted after ethical clearance and with informed consent in local language. On admission a detailed history was taken, clinical examination was performed and gestation age was assessed. All cases underwent ultrasonography examination for estimation of amniotic fluid index by Phelan’s method. Parameters noted were age, parity, risk factors, mode of delivery and perinatal outcome. Results were analyzed with special emphasis on perinatal outcome by using percentage and proportion.

Inclusion Criteria

• Gestational age after 37 weeks of gestation calculated from reliable date or early ultrasound at the first trimester
• Intact membranes
• Singleton gestation
• Amniotic fluid index < 5 cm

Exclusion Criteria

• Women with <37 completed weeks of gestation
• Ruptured membranes
• Multiple pregnancy
• Intra uterine death

TABLE 1: Age wise distribution of patients

In our study, 130 (65%) patients were in the age group 21 to 25 year and only 14 (7%) were above the age of 30 year (Table 1).

TABLE 2: Parity status in cases with oligohydramnios

A total 64% of the females with oligohydramnios were primigravida and 36% were multigravida in this study (Table 2).

TABLE 3: Risk factors identified for oligohydramnios

Table 3 shows the distribution of patients according to the risk factors identified with oligohydramnios. Majority of our patients (45%) did not have any specific cause for oligohydramnios. Hypertensive disorders were associated with 21% of the cases and post-dated pregnancy in 13% of the cases. Fetal risk factors occurred in a few patients as shown in the table.

TABLE 4: Mode of delivery

In our study, 61% patients with oligohydramnios had vaginal delivery and 39% patients underwent caesarean section (Table 4).

TABLE 5: Indication of caesarean section

Table 5 shows the indications of caesarean section in our patients with oligohydramnios. Fetal distress being the most common (55%), followed by elective caesarean (14%). Fetal growth restriction was seen in 12%.

TABLE 6: Perinatal outcome

Table 6 depicts perinatal outcome in patients with oligohydramnios. Birth weight <2.5kg was found in 65% patients and >2.5kg in 35% patients. Apgar score was calculated in all the newborns at 1 minute and 5 minute. 21% had Apgar score <7 at 1 minue and 7% had a score of <7 at 5 minute. Meconium aspiration syndrome was seen in 23% patients. 23% required neonatal resuscitation and NICU admission was required in 26% due to presence of factors like respiratory distress, fetal growth restriction, meconium aspiration syndrome, low birth weight. However, 1% stillbirth was also observed.

The present study was conducted on 200 cases with oligohydramnios, having gestational age more than 37 weeks and these patients were analyzed for any associated risk factors and perinatal outcome. It was observed that the majority (65%) of the patients were in the age group 21-25year. Similar findings were found in the study conducted by Madhavi K et al., Biradar KD et al. (5,6) Almost 64% patients were primigravida in our study. Results were similar to study conducted by Ahmar R et al., Bumrah S et al. where primigravida participants were 64.4% and 55% respectively.^(7,8) In the study done by Casey BM et al. there were no significant relations of age and parity with oligohydramnios.⁽⁹⁾

The medical and obstetric risk factors were noted, and it was found that 45% patients in our study had no risk factor. This was similar to the findings of Zhang J et al. where around half of the cases had isolated oligohydramnios with no risk factor. (10) It was found that hypertensive disorders of pregnancy was the second most common risk factor, associated in almost 21% of the cases, which is similar to the studies conducted by Bumrah S et al., by Naik AS et al. where hypertensive disorders were found in 20% patients. (8.11) Postdated pregnancy was found in 13% of our cases which is at par with the study conducted by Naik AS et al. who found it to be 13.5%.⁽¹¹⁾ Fetal growth restriction was seen in12% patients.

In our study, 61% patients delivered vaginally and 39% patients had caesarean section which is comparable to study conducted by Dalal N et al. where 59% patients had a vaginal delivery.⁽¹²⁾ Of the caesarean sections 55% were done for fetal distress. Baron C et al. found that caesarean rate for fetal distress was significantly more often in oligohydramnios than normal AFI.⁽¹³⁾ 14% patients had elective caesarean section which is at par with the study conducted by Molla M et al.⁽¹⁴⁾

In terms of perinatal outcome, the rate of low birth weight babies (<2.5kg) was 65%. Similar observations were found by Madhavi K et al. where low birth weight babies were found in 68% patients and Fatema J et al. showing low birth weight babies in 48% of patients.^(5,15)

Apgar score was calculated in all the newborns at 1 minute and 5 minute. 21% had Apgar score <7 at 1 minute. Similar finding were found in the study conducted by Kiran K et al. where 21% had Apgar score <7 at 1 minute. (16) Meconium aspiration syndrome was seen in 23% patients which is similar to the study conducted by Molla M et al. (14) 23% required neonatal resuscitation. 26% required NICU admission similar to study performed by Bumrah S et al. (8) In the present study, 1% stillbirth was observed. Similar finding were found in the study conducted by Molla M et al. where 1.5% stillbirth was observed.⁽¹⁴⁾

Regular antenatal surveillance in third trimester helps to detect oligohydramnios, which requires close fetal monitoring and timely intervention, for a good perinatal outcome.

LIMITATIONS

It was a single center study with a relatively small sample size; hence our findings may not be generalised in all the pregnancies.

Oligohydramnios when detected in late second trimester or early third trimester of pregnancy is generally associated with other antenatal maternal or fetal co-morbid conditions which affect the outcome of pregnancy. AFI is an important and convenient screening test for prediction of perinatal outcome. Severity of oligohydramnios increases the rate of operative intervention and adverse perinatal outcome. Every case of oligohydramnios needs careful evaluation, parental counselling and individualized decision regarding timing and mode of delivery to improve the perinatal outcome.

1.       Phelan JP, Smith CV, Small M. Amniotic fluid volume assessment with the four quadrant technique at 36 to 42 weeks gestation. J Reprod Med. 1987;32:540- 42

2.       Kehl S, Schelkle A, Thomas A, Puhl A, Meqdad K, Tuschy B et al. Single deepest vertical pocket or amniotic fluid index as evaluation test for predictingadverse pregnancy outcome (SAFE trial):-dmulticenter, open-label, randomized controlled trial. Ultrasound Obstet Gynecol. 2016;47(6):674-9.

3.       Moore TR. Clinical assessment of amniotic fluid. Clin Obstet Gynaecol. 1997;40(2):303-13

4.       Sherer DM. A review of amniotic fluid dynamics and the enigma of isolated oligohydramnios. Am J Perinatol. 2002;19:253-66.

5.       Madhavi K, Rao PC. Clinical Study of oligohydramnios, mode of delivery and perinatal outcome. IOSR Journal of Dental and Medical Sciences. 2015;14 (4):6-11.

6.       Biradar KD, Shamanewadi AN. Maternal and perinatal outcome in oligohydramnios: study from a tertiary care hospital, Bangalore, Karnataka, India. Int J Reprod Contracept Obstet Gynecol 2016;5:2291-4.

7.       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.

8.       Bumrah S, Grover S, Kaur K, Rajora P, Tapasvi I. Clinico-epidemiologic profile and perinatal outcome of patients with oligohydramnios in third trimester in a tertiary care hospital. Int J Reprod Contracept Obstet Gynecol 2023;12:1222-6.

9.       Casey BM, McIntire DD, Bloom SL, Lucas MJ, Santos R, Twickler DM, et al. Pregnancy outcomes after antepartum diagnosis of oligohydramnios at or beyond 34 weeks’ of gestation. Am J Obstet Gynecol. 2000;182(4):909-12.

10.    Zhang J, Troendle J, Meikle S, Klebanoff MA, Rayburn WF. Isolated oligohydramnios is not associated with adverse perinatal outcomes. BJOG. 2004;111(3):220-5.

11.    Naik AS, Chadha MT. A Study of Effect of Oligohydramnios on the Obstetric and Perinatal Outcome. Sch. J App Med Sci. 2018;6(11):4562-7.

12.    Dalal N, Malhotra A. Perinatal outcome in cases of severe oligohydramnios. Int J Reprod Contracept Obstet Gynecol 2019;8:1538-41.

13.    Baron C, Morgan M, Garite T. The impact of amniotic fluid volume assessed intrapartum on perinatal outcome 1995; 173: 167-74.

14.    Molla M, Mengistu Z, Tsehaye W and Sisay G (2023) Magnitude and associated factors of adverse perinatal outcomes among women with oligohydramnios at 3rd trimester at University of Gondar comprehensive specialized hospital, North West Ethiopia. Front. Glob. Womens Health 3:958617. doi: 10.3389/fgwh.2022.958617

15.    Fatema J, Chowdhury TI, Chakma B, Parveen M, Kamrunnahar, Rahman AKMS, Das TR. Oligohydramnios and Its Maternal and Neonatal Outcomes: A Single Centre Study. Obstetrics and Gynecology Research. 7 (2024): 08-15.

16.    Kiran Kumari, Pawan Kumar Bharti. Clinical study of maternal and perinatal outcome in oligohydramnios in term patients at a tertiary care institute. MedPulse International Journal of Gynaecology. June 2021; 18(3): 61-65.