oligo research article.pdf

Bangal V B et. al. / JPBMS, 2011, 12 (05)

1 Journal of Pharmaceutical and Biomedical Sciences (JPBMS), Vol. 12, Issue 12

Available online at www.jpbms.info

JPBMS

JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL SCIENCES

Incidence of oligohydramnios during pregnancy and its effects on maternal and perinatal outcome

* Vidyadhar B. Bangal1, Purushottam A. Giri2, Bhushan M. Sali3

1Professor and Head, Dept. of Obstetrics and Gynaecology (OBGY), Rural Medical College & Pravara Rural Hospital of Pravara Institute of Medical Sciences (Deemed University), Loni, Dist. Ahmednagar, Maharashtra, India.

2Assistant Professor, Dept. of Community Medicine (PSM), Rural Medical College & Pravara Rural Hospital of Pravara Institute of Medical Sciences (Deemed University), Loni Dist. Ahmednagar, Maharashtra, India.

3Postgraduate student, Dept. of Obstetrics and Gynaecology (OBGY), Rural Medical College & Pravara Rural Hospital of Pravara Institute of Medical Sciences (Deemed University), Loni Dist. Ahmednagar, Maharashtra, India.

Abstract: Oligohydramnios or reduced amount of amniotic fluid volume is a commonly observed obstetric problem during third trimester of pregnancy. It accompanies a broad range of reproductive disorders including anomalies of fetus and functional disorders of mother, fetus and placenta. Reduced amniotic fluid volume is associated with adverse perinatal outcome. A prospective hospital based study of total 100 cases of oligohydramnios coming for delivery to Pravara Rural Hospital, Loni was undertaken over a period of two years from October 2007 to September 2009. The information regarding bio-social characteristics, maternal and perinatal outcome were collected and results were analyzed by using percentage and proportion. In the present study, the majority of the cases( 78%) were unbooked and belonged to the age group of 20-30 years and had associated maternal or fetal complications. Postdated pregnancy, pregnancy induced hypertension and fetal congenital anomalies were the commonest complications associated with oligohydramnios. Forty four percent cases were delivered by caesarean section. Overall perinatal mortality was 24%. Cases with severe oligohydramnios and anhydramnios were associated with intrapartum fetal heart rate abnormalities, (16%) low Apgar score and (8%) meconium aspiration syndrome. Every case of oligohydramnios needs careful evaluation, parental counseling and individualized decision regarding timing and mode of delivery. Continuous intrapartum fetal monitoring and good neonatal care support is essential for optimum perinatal outcome. Keywords: Maternal outcome, perinatal outcome, Oligohydramnios

Introduction: Oligohydramnios or reduced volume of amniotic fluid poses challenge to obstetrician, when it is diagnosed before term. Oligohydramnios can develop in any trimester, although it is more common in third trimester. [1] About 12% of women, whose pregnancies continue for two weeks beyond expected date of delivery; develop oligohydramnios due to declining placental function. Oligohydramnios accompanies a broad range of reproductive disorders including anomalies of fetus and functional disorders of mother, fetus and placenta. Decreased amount of amniotic fluid, particularly in third trimester, has been associated with multiple fetal risks like, pulmonary hypoplasia and intrauterine growth restriction. Oligohydramnios may cause compression of umbilical cord, leading to fetal distress during labour. Oligohydramnios is found to be associated with an increased risk of caesarean delivery for fetal distress, low Apgar score and high perinatal morbidity and mortality [2]. Hence, the present study was carried out to find out the incidence of oligohydramnios during pregnancy and its effect on maternal and perinatal outcome. Material & Methods: A retrospective hospital based study was carried out in the department of Obstetrics and Gynaecology of Rural

Medical College and Pravara Rural Hospital- a tertiary level health care referral centre in Loni, Maharashtra, India over a period of 2 years from October 2007 to September 2009. Hundred pregnant women in 3rd trimester of pregnancy, diagnosed as oligohydramnios with amniotic fluid index (AFI) less than 5 cm and intact membranes were included in the study. Findings were analyzed with the special emphasis on bio-social characteristics of the patient and maternal and perinatal outcome. The ethical committee of the institute had approved the study. Results were analyzed by using percentage and proportion. Results: It was observed (table 1) that, 78% women with oligohydramnios were in the age group of 20-29 years. The mean (± SD) maternal age was 22.8 ± 4.2 years. By gestational age, 22% of women were in the gestational age group of 34-36 weeks followed by 20% women in 38-40 and >40 weeks. The mean gestational age was 36.7 ± 4.1 weeks. By parity, 54% women were primigravidas followed by 46% multigravidas. It was observed that (table 2), pregnancy induced hypertension (16%), postdated pregnancy (16%) and

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Research article



anhydramnios (10%) were commonly seen in women with oligohydramnios. As regards to mode of delivery, it was observed that, 56% had spontaneous vaginal delivery and 44% had operative/assisted delivery. Birth asphyxia (Apgar score of <7 at one minute and five minute) was more common in the babies delivered in cases of oligohydramnios. Neonatal morbidity was mainly due to meconium aspiration and neonatal sepsis. High perinatal mortality (24%) was observed in the present study.

Bio-social characteristics Oligohydramnios women (n=100)

1. Maternal age <20 yrs 20 - 29 yrs ≥ 30 yrs

16 78 06

Mean ± SD 22.88 yrs ± 4.24 yrs 2. Gestational age

30-32 weeks 32-34 weeks 34-36 weeks 36-38 weeks 38-40 weeks

>40 weeks

08 14 22 16 20 20

Mean± SD 36.72 weeks ± 4.11 weeks 3. By Amniotic Fluid Index

0 1 2 3 4 5

10 06 28 06 30 20

Mean± SD 3.00 ± 1.04

4. By birth weight <1000 gms

1000-2000 gms 2000-3000 gms

>3000 gms

02 38 58 02

Mean± SD 2140.00 gms ± 0.51 gms 5. Parity

Primigravidas Multigravidas

54 46

Mean± SD 1.2 ± 1.5 (Data indicates both number and percentage) Table 2: Maternal and perinatal outcome in oligohydramnios (n=100)

Variables No. of cases 1. Maternal complications

Pregnancy induced hypertension Postdate Intrauterine growth restriction Preterm delivery Anhydramnios Fetal anamolies

16 16 14 14 10 08

2. Mode of delivery Spontaneous vaginal delivery Operative/assisted delivery

56 44

3 Neonatal morbidity Meconium aspiration Neonatal sepsis

04 04

4. Apgar score (< 7) At 1 minute At 5 minute

10 16

5. Perinatal mortality Still births Early neonatal death

08 16

(Data indicates both number and percentage) Discussion: In the present study, 78% of cases were in the age group 20 to 29 years, as compared to other age groups, reflecting the child bearing age of most of the women with the mean (±SD) maternal age of 22.8 ± 4.2 years. Similar studies by Chauhan P et. al. [3], Jun Zhang et. al. [4] and Everett F et. al.

[5] found that the mean maternal age were 23.6 ± 6.5 years, 28.4 ± 3.4 years and 23.8 ± 5.7 years respectively. The mean gestational age in the present study was 36.7 ± 4.1 weeks. Similar studies by Jun Zhang et. al. [4], Casey B et al .[6] , Everett F et. al. [5] and Iffath A et. al.[ 7] found that, the mean gestational age were 38.1 ± 3.3 weeks, 37.5 ± 2 weeks, 34.3 ± 2.1 weeks, and (mean ± SD) was 36.3 ± 2 weeks respectively. These findings indicate that the problem of oligohydramnios was more common in the later part of pregnancy. It is mainly due to physiological or pathological causes of reduced placental perfusion near term. In the present study, the incidence of oligohydramnios was 0.67%. Similar study by Jun Zhang et. al. [4] reported the incidence as 1.5%. Divon M et. al. [8] found oligohydramnios in 1.2% in their cases. Casey B et al.6 found that 2.3% cases were complicated by oligohydramnios. Elliot H et. al. [9] found that, the incidence of oligohydramnios was 3.9% in their study. Varma T R et. al. [10] found that, the incidence was 3.1% in their study. Chauhan P et. al. [19] studied two groups of patients. First group had AFI less than 5cm and second with AFI less than 5th percentile for that gestational age. The mean amniotic fluid index was 3.9 ± 2.1 cm (AFI less than 5th percentile) and 3 ± 1.5 cm in patients with AFI less than 5cm. The mean amniotic fluid index (AFI) in the present study was 3.00 ± 1.04cm. Sadovsky Y et. al. [20] in their study, found that the mean amniotic fluid index was 2.9 cm. Obstetrical complications frequently associated with oligohydramnios were pregnancy induced hypertension(PIH), postdatism, intrauterine growth restriction, fetal renal anomalies, prematurity and intrauterine death of the fetus. In the present study 78% cases had associated obstetrical complications; acting singly or in combination for causing oligohydramnios. PIH was present in 16% cases. Golan A et al.12 in his study, found maternal hypertension in 22.1% cases. Cesarean section was performed in 35.25% of these cases. Mercer L J et. al. [13] found that preeclampsia was present in 24.7% of cases with decreased fluid. Study by Chauhan P et. al. [3]

reported, preeclampsia in 12% cases. They concluded that the incidence of oligohydramnios ranges from 10 to 30 % in hypertensive patients requiring hospitalization. Sixteen percent cases had postdated pregnancies in the present study. Clement D et. al. [21] studied six cases of postdatism, in which amniotic fluid volume diminished abruptly over 24 hours. Bowen Chattoor JS et. al. [22], in their study evaluated the relationship between amniotic fluid index and perinatal outcomes in fifty five postdate pregnancies. Oligohydramnios was noted in four (7.2%) cases. In the present study, intra uterine growth restriction was present in 20% cases and the rate of caesarean section was 44% and that of vaginal delivery was 56%. Study by Casey B et. al. [6] found that, there was increased rate of induction of labour (42%) and Cesarean section (32%) in oligohydramnios cases. Jun Zhang et al.4 found that, the overall cesarean delivery rates were similar between women with oligohydramnios and the controls (24% Vs 19%). Golan A et. al. [12] et al found that, the cesarean section was performed in 35.2% of pregnancies. In the present study, the apgar score was noted at 1 and 5 minutes after birth. Sixteen babies (16%) had low Apgar score (less than 7 at 5 min). Out of 16 babies with low Apgar score, eight died during neonatal period. Three babies with low Apgar score were delivered by caesarian



section. Out of these 3 babies, one died during neonatal period due to non-immune hydrops fetalis. In a similar study by Casey B et. al.[6] (6%) babies had Apgar score of less than 3 at 5 minute. Out of these nine babies, seven died during neonatal period. Jun Zhang et. al. [4] found that an Apgar score of <7 at 1 minute was present in fifteen Six babies had Apgar score of <7 at 5 minute. Desai P et. al. [14] found that three babies with Apgar score less than 7 at 5 minute as against only one in control group. In a similar study by Locatelli A et. al. [15] of 341 patients with oligohydramnios, found no significant difference for Apgar score of less than 7 at 5 minute in study and control group. In the present study, four (8%) babies developed meconium aspiration. All four babies were admitted in NICU for further management. Three babies were delivered by caesarean section and one by vaginal route. Two babies died in neonatal period. Causes of deaths were meconium aspiration syndrome and development of septicemia. Babies who died due to meconium aspiration syndrome were of 37.5 weeks and 39.3 weeks of gestation with birth weight of 1.3 kg and 2.5kg respectively. Casey B et. al. [6] studied 6423 patients, who underwent ultrasonography at more than 34 weeks gestation and found that 147 (2.3%) cases were complicated by oligohydramnios. Meconium stained amniotic fluid was identified, less often in pregnancies complicated by oligohydramnios (6% vs. 15%, P=0.004). Notably; the incidence of meconium aspiration syndrome in infants with oligohydramnios was significantly higher despite the diminished identification of meconium stained amniotic fluid. Bowen Chattoor JS et. al. [22] studied perinatal outcome in 55 postdate pregnancies. Oligohydramnios was noted in four patients. All 4 babies were admitted with meconium aspiration. One died due to this complication. In the present study, there were 92% live births and 8% still births. Sixteen percent babies died in neonatal period. The gross perinatal mortality was 24% in present study. Out of 12 perinatal deaths, 11 deaths were seen in unregistered cases. Chhabra S et. al. [16] reported very high (87.7%) perinatal mortality in their study. Wolff F et. al. [17] found that the perinatal mortality in their study was 7.2%. Apel-Sarid L et. al. [18] found that the perinatal mortality was 9.9%. Chamberlin PF et. al. [23] calculated the gross and corrected perinatal mortality rate in patients with decreased qualitative amniotic fluid volume and found it to be 188/1000 and 109/1000 respectively. Overall, the perinatal mortality is markedly increased in patients with oligohydramnios. The lack of amniotic fluid allows compression of fetal abdomen, which limits the movement of the diaphragm.

Conclusion: Oligohydramnios is being detected more often these days, due to routinely performed obstetric ultrasonography. Pregnancy induced hypertension and post dated pregnancies are the commonest causes of reduced amniotic fluid during third trimester of pregnancy. Anomalies of the fetal renal system are responsible for oligohydramnios in second and third trimester. The time and mode of delivery of these cases depends on severity of oligohydramnios and status of fetal wellbeing. Caesarean section is mostly required for cases with anhydramnios and intrapartum fetal heart rate abnormalities. Babies are relatively more prone for certain complications, like

intrapartum fetal distress, meconium aspiration syndrome and birth asphyxia. Adverse perinatal outcome can be avoided by careful intrapartum fetal heart rate monitoring. Every case of oligohydramnios needs careful antenatal evaluation, parental counseling, individualized decision regarding timing and mode of delivery. Continuous intrapartum fetal monitoring and good neonatal care are necessary for better perinatal outcome. Acknowledgement: We acknowledge the cooperation extended by Management of Pravara Medical Trust and The Principal, Rural Medical College, Loni, Maharashtra, India References: 1.Park K. Preventive medicine in obstetric, Paediatrics and geriatrics: Park's Text Book of Preventive and Social Medicine. 20th edition. Jabalpur: M/S Banarasi Das Bhanot; 2009; 479-483. 2.D. C. Dutta: Textbook of Obstetrics, 6th edition 2004:37. 3.Chauhan SP, Hendrix NW: Intrapartum oligohydramnios does not predict adverse peripartum outcome among high risk parturient. Am J Obstet Gynecol, 1997; 176(6):1130-1136. 4.Jun Zhang, James Troendle: Isolated oligohydramnios is not associated with adverse perinatal outcome. Int J Gynaecol Obstet Mar 2004;3:220-225. 5.Everett FM, Thomas EN: Measurement of amniotic fluid volume-Accuracy of ultrasonography technique. Am J Obstet Gynecol 1992; 167:1533-7. 6.Casey Brian M, Donald D McIntire: Pregnancy outcomes after antepartum diagnosis of oligohydramnios at or beyond 34 weeks' gestation. Am J Obstet Gynecol, April 2000; 182(4): 909-912. 7.Hoskins IA, Friden FJ: Variable deceleration in reactive non stress test with decreased amniotic fluid index predicts fetal compromises. Am J Obstet Gynecol 1991; 165(4):1094-1098. 8.Divon MY, Marks, Henderson CE: Longitudinal measurement of amniotic fluid index in post term pregnancies and its association with fetal outcome. Am J Obstet Gynecol 1995; 172:142. 9.Elliot H. Phillipson, Robert J. Sokol: Oligohydramnios – Clinical association and predictive value for intrauterine growth retardation. Am J Obstet Gynecol 1983; 146:271. 10.Varma TR, Bateman S: Ultrasound evaluation of amniotic fluid -outcome of pregnancies with severe oligohydramnios. Int J Gynaecol Obstet Oct 1988; 27(2):185-92. 11.Corosu R, Moretti S: Clinical considerations on oligohydramnios. Minerva Ginecol Jun 1999; 51(6):219-22. 12.Golan A, Lin G : Oligohydramnios - maternal complications and fetal outcome in 145 cases. Gynecol Obstet Invest 1994; 37(2):91-5. 13.Mercer Lane, L.G. Brown: A survey of pregnancies complicated by decreased amniotic fluid. Am J Obstet Gynecol 1984; 149:355-361. 14.Desai P, Patel P, Gupta A: Decreased amniotic fluid index in low risk pregnancy – Any significance? J Obstet Gynecol Int Sep 2004; 54(5): 464:466. 15.Locatelli A, Vergani P et al: Perinatal outcome associated with oligohydramnios in uncomplicated term pregnancies. Arch Gynecol Obstet 2004; 269(2):130-133.



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Conflict of Interest: - None Source of funding: - Not declared *Corresponding Author:- Dr. Vidyadhar B. Bangal., Professor and Head, Dept. of Obstetrics and Gynaecology (OBGY), Rural Medical College, Loni, Dist. Ahmednagar, Maharashtra, India Pin- 413736 Contact no- (+91) 02422- 273600, 09822096723. .

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