Introduction
Oligohydramnios, if the amniotic fluid index is less than 5 or if the single deepest vertical pocket of liquor is less than 2 cm long. Description of the amniotic fluid volume as increased or decreased is based on sonographical criteria.1 Oligohydramnios complicates 1% to 2% of pregnancies.2
Normal index of amniotic fluid is 8.1-20 cms. Amniotic fluid index between 5.1 and 8cm is termed as Borderline oligohydramnios.
Amniotic fluid offers a low-resistance atmosphere for foetal development and growth. It creates the cushion impact against the limiting boundaries of the uterus. It provides adequate space for fetal musculoskeletal development, contributes to normal lung formation and prevents umbilical cord compression, placental growth restriction and hence protects the foetus against vascular and nutritional compromises.3
The incidence of maternal and foetal complications is increased in Oligohydramnios. It may be related to uteroplacental insufficiency, preeclampsia, asthma, diabetes, coronary failure, congenital defects, idiopathic limitation of foetal development, foetal hypoxia. Oligohydramnios, is presumed to be because of chronic in utero stress, in absence of any foetal renal abnormality or genitourinary obstruction.4
Oligohydramnios may have a major effect on maternal and foetal outcomes.5
Fetal complications
Cord compression and fetal distress, Fetal pulmonary hypoplasia & stillbirth, Fetal growth restriction, Low Apgar score, NICU admissions, overall increased perinatal morbidity and mortality
Maternal complications
Prolonged labour due to inertia.
Induction of labour.
Increased operative interference and related morbidity and mortality. By diagnosing such cases and with early & timely intervention can prevent most of the complications. In case of irreversible complications having occurred, termination of pregnancy can be considered.
This clinical study was conducted in KIMS hospital and research centre, Bengaluru, on 80 cases of oligohydramnios to know the maternal and fetal outcome.
Materials and Methods
Source of data
This study was conducted on all singleton, non-anomalous, low risk pregnant women with AFI less than or equal to 5 with intact membranes and gestational age between 28-42 weeks at KIMS Hospital in the Department of Obstetrics and Gynecology after taking informed consent.
Methodology
After obtaining approval and clearance from the institutional ethical committee, The pregnant woman meeting the inclusion and exclusion criteria were enrolled in the study after obtaining informed consent
Data was collected using a proforma by consecutive sampling method.
Detailed clinical history including obstetric, menstrual, past and personal history were taken and detailed examination was done. Basic routine blood investigations were done.
Liquor volume was estimated by ultrasonography by measuring the AFI by four quadrant technique of phelan or when the single deepest vertical pocket measures less than 2cms. Delivery was optimized depending on antepartum fetal surveillance.
Results
Table 1
Gravidity distribution
|
Gravida |
Number |
Percentage |
|
Primi |
50 |
62.5 |
|
2 |
14 |
17.5 |
|
3 |
11 |
13.8 |
|
4 |
5 |
6.2 |
|
Total |
80 |
100.0 |
Table 2
Gestational age distribution - Gestational age was divided according to WHO and ACOG guidelines into 6 categories.
Table 3
Gestational age distribution and AFI categories
Table 4
Gestational age and Doppler changes
In this study, Out of 80 patients, antenatal scan of 16 patients (20%) showed doppler changes in the form of uteroplacental insufficiency (10 cases), decreased diastolic flow in umbilical artery (2 cases) absent flow (1 case) and reversed end diastolic flow in umbilical artery (2 cases), increased diastolic flow in MCA (1 case). Out of 16 babies, 9 (11.25%) babies had IUGR with doppler changes.
Table 5
Gestational age and IUGR
In this study, out of 80 cases, antenatal scan of 20 patients showed IUGR. 6 were preterm and 14 were term cases. Out of 20 cases whose scan showed IUGR, 9 cases had IUGR with doppler changes.
Table 6
Mode of delivery
|
Mode of delivery |
Number |
Percentage |
|
Vaginal |
31 |
38.75 |
|
LSCS |
49 |
61.25 |
|
Total |
80 |
100 |
Table 7
Gestational age and mode of onset of labour and mode of delivery
Table 8
Indication for LSCS
|
Indication |
Number |
Percentage |
|
Fetal distress |
18 |
36.7 |
|
Non-progression of labour |
6 |
12.2 |
|
CPD |
3 |
6.1 |
|
Failed induction |
5 |
10.2 |
|
IUGR with doppler changes |
7 |
14.4 |
|
Previous LSCS |
5 |
10.2 |
|
MSAF |
5 |
10.2 |
|
Total |
49 |
100.0 |
Table 9
Gestational age and Fetal weight distribution
Table 10
Nature of amniotic fluid
|
Liquor |
Number |
Percentage |
|
Absent |
3 |
3.7 |
|
Clear |
65 |
81.3 |
|
MSAF I |
2 |
2.5 |
|
MSAF II |
4 |
5.0 |
|
MSAF III |
6 |
7.5 |
|
Total |
80 |
100.0 |
Table 11
Gestational age and APGAR at 1 minute and 5 minutes
Discussion
This study was carried out to observe the effect of isolated oligohydramnios on Obstetric and perinatal outcome.
In this study, maximum women i.e, 33 cases(41%) were in the age group between 21-25 years. In the study by Ghike et al. mean age of women was 24.656 which is comparable to the present study with a mean age of 24.8 years. A study by Biradar et al. showed mean age of 22.4 years.7 Minimum age in the study was 19 years and maximum age was 37 years. Study showed there was no significant relation between maternal age and incidence of oligohydramnios.
Out of 80 cases, 50 cases (62.5%) were primigravida, 14 cases were 2nd gravida, 11 cases were 3rd gravida and 5 cases were 4th gravida, indicating that incidence of oligohydramnios is more in primigravidae. A study of Chetani et al8 observed that 63% of women were primigravida which is comparable to the present study with 62.5% of women who were primigravida.
Study shows, maximum number of cases were in the early term gestation, i.e., between 37-38+6 weeks, a total of 35 cases (44%). Gestational age was divided according to WHO and ACOG guidelines8 into 5 categories. There were a total of 13 preterm cases and 67 term cases.
There were a total of 2 cases with AFI = 0, 10 cases with AFI ranging between 1-2, 15 cases with AFI ranging between 2.1-3, 11 cases with AFI between 3.1-4, and 42 cases with AFI ranging between 4.1 to 5.
Out of 80 cases, 61 patients (76.25%) had reassuring NST on admission and 19(23.75%) of them had non reassuring pattern.
In this study, out of 80 patients, antenatal scan of 16 patients (20%) showed doppler changes in the form of uteroplacental insufficiency (10 cases). Decreased diastolic flow in umbilical artery (2 cases), absent flow (1 case) and reversed end diastolic flow (2 cases), increased diastolic flow in MCA(1 case). Out of 16 babies, 9 (11.25%) babies had IUGR with doppler changes.
Out of 80 deliveries in the study, 20 babies (25%) had IUGR. Out of 20 babies, 9 babies(11.25%) had doppler changes. 6 preterm and 14 term babies were diagnosed with IUGR. 11 babies (55%) were shifted to NICU. Maximum number of babies who had IUGR were in the early term group(37-38+6 weeks).
Out of 14 term cases, 10 cases underwent LSCS for various reasons like fetal distress (5 cases), failed induction (2 cases), IUGR with doppler changes (2 cases), previous LSCS with IUGR 1 case and 4 cases delivered vaginally. The weight of the babies diagnosed with IUGR were between 1.6 kgs to 2.4 kgs.
Out of 80 patients, 31 patients(38.7%) delivered vaginally and 49 patients (61.25%) underwent LSCS. A study Biradar KD et al7 which observed a caesarean section rate of 62% is comparable to our study which had a caesarean section rate of 61%.
In this study, Out of 80 cases, 49 cases (61%) were induced. 3 preterm cases and 46 term cases were induced. Out of 49 induced cases, 23 cases (47%) delivered vaginally and 26 cases(53%) underwent LSCS. 17 cases (21.4%) out of 80 cases directly underwent LSCS.
Out of 80 cases, 49 cases underwent LSCS and the most common indication was Fetal distress with 18 cases (36.7%). IUGR with doppler changes with 7 cases (14.4%), non progression of labour 6 cases (12%), failed induction, previous lscs and MSAF were 5 cases each (10.2%) and CPD with 3 cases (6.1%). A study conducted Sunanda KM et al. showed a LSCS rate9 of 38% for fetal distress which is comparable to present study with LSCS rate of 36% for fetal distress.
Out of 80 deliveries, fetal weight distribution is as follows, between 1000-1499 gms, there was 1 baby with birth weight of 1 kg. Between 1500-1999g, there were 8 babies(10%). Between 2000-2499g, there were 25 babies(31%). Between 2500-2999g, there were 30 babies(37.5%). Between 3000-3500g, there were 16 babies(20%). According to study conducted by Chetani M et al.10 babies who weighed less than 2.5kgs in study group constituted 42% which is comparable to the present study with 42.5% of babies weighing less than 2.5kgs.
Nature of amniotic fluid – clear liquor was found in 65 cases, (81% cases), meconium stained liquor was found in 12 cases (15%) and liquor was absent in 3 cases (4%). Although meconium stained liquor was found in less number of cases, 8 out of 12 babies were admitted to for meconium aspiration syndrome.
Out of 80 babies, APGAR score of </=7 at 1 minute was seen in 12 babies (15%) and more than 7 was seen in 68 babies (85%). APGAR score of all the neonates at 5 minutes was more than 7/10. In study by Sowmya K et al,11 APGAR score <7 at 1 minute was seen in 14%. Similar studies done by Biradar et al,7 Patel PK et al,12 Vidyasagar V et al,13 Casey B et al, Sriya V et al14 and Zhang J et al15 found APGAR score <7 at 1 minute in 26%, 34.6%, 35%, 6%, 38.8%, 13.3% respectively.7, 13, 12, 14, 15
After delivery, 50 babies (62%) were given mother’s side and 30 babies (37%) were admitted to NICU. In study by Biradar K et al,7 NICU admission was required for 40% of newborns. In another study by Madhavi K et al,16 NICU admission was required for 34% of newborns. The indication for NICU admission in this study were, Transient tachypnoea of newborn – 9 cases (33%), Meconium aspiration syndrome 8 cases (30%), prematurity 7 cases (26%), followed by birth asphyxia, perinatal depression and IUGR 1 case each.
Summary
Out of 80 cases, in terms of gravidity distribution, the incidence of oligohydramnios was more in primigravidae.
Gestational age was divided according to WHO and ACOG guidelines into 5 categories. There were a total of 13 preterm cases and 67 term cases.
There were 2 cases with AFI = 0, 10 cases with AFI between 1-2, 15 cases with AFI between 2.1-3, 11 cases with AFI between 3.1 – 4, and 42 cases with AFI between 4.1 to 5.
Out of 80 cases, 61 patients(76.25%) had reassuring NST on admission and 19(23.75%) of them had non reassuring pattern.
In this study, Out of 80 patients, antenatal scan of 16 patients (20%) showed doppler changes. Uteroplacental insufficiency in 10 cases, Decreased diastolic flow in umbilical artery in 2 cases, absent flow in 1 case and reversed end diastolic flow in 2 cases, increased diastolic flow in MCA in 1 case.
Out of 80 deliveries in the study, 20 babies (25%) had IUGR (6 preterm and 14 term babies). Out of 20 babies, 9 babies(11.5%) had IUGR with doppler changes. 11 babies (55%) were shifted to NICU. Out of 6 preterm cases, 5 cases underwent emergency LSCS i/v/o IUGR with doppler changes. 1 case underwent LSCS for failed induction. Out of 14 term cases, 10 cases underwent LSCS for various reasons like fetal distress (5 cases), failed induction (2 cases), IUGR with doppler changes (2 cases), previous lscs with IUGR 1 case and 4 cases delivered vaginally. The weight of the babies diagnosed with IUGR were between 1.6 kgs to 2.4 kgs.
Out of 80 patients, 31 patients(38.7%) delivered vaginally and 49 patients (61.25%) underwent LSCS. Out of 80 cases, 14 cases (17%), (2 preterm cases and 12 term cases)had spontaneous onset of labour, out of which 8 cases delivered vaginally and 6 cases underwent LSCS. 49 out of 80 cases (61%) were induced. (3 preterm cases and 46 term cases) out of 49 induced cases, 23 cases (47%) delivered vaginally and 26 cases(53%) underwent LSCS.
Out of 80 cases, 49 cases underwent LSCS and the most common indication was fetal distress with 18 cases (36.7%). Followed by IUGR with doppler changes with 7 cases (14.4%), non progression of labour 6 cases (12%), followed by failed induction, previous lscs and MSAF were 5 cases each (10.2%) and CPD with 3 cases (6.1%).
Out of 80 deliveries, between 1000-1499 gms, there was 1 baby with birth weight of 1 kg. Between 1500-1999g, there were 8 babies(10%). Between 2000-2499g, there were 25 babies(31%). Between 2500-2999g, there were 30 babies (37.5%). Between 3000-3500g, there were 16 babies(20%).
Clear liquor was found in 65 cases, (81% cases), meconium stained liquor was found in 12 cases (15%) and liquor was absent in 3 cases (4%). Although meconium stained liquor was found in less number of cases, 8 out of 12 babies were admitted to NICU for meconium aspiration syndrome.
Out of 80 babies, APGAR score of </=7 at 1 minute was seen in 12 babies (15%) and more than 7 was seen in 68 babies (85%). APGAR score of all the neonates at 5 minutes was more than 7/10.
After delivery, 50 babies (62%) were given mother’s side and 30 babies (37%) were admitted to NICU. The indication for NICU admission in this study were, Transient tachypnoea of newborn – 9 cases (33%), Meconium aspiration syndrome 8 cases (30%), prematurity 7 cases (26%), followed by birth asphyxia, perinatal depression and IUGR 1 case each.
Table 13
Summarizing the obstetric and perinatal outcome in the present study
|
Induction rate |
61% |
|
LSCS |
61% |
|
Meconium stained liquor |
15% |
|
Birth weight <2.5 kgs |
42.5% |
|
1 minute APGAR < /=7 |
15% |
|
NICU admissions |
37.5% |
|
Mortality(maternal and perinatal) |
0% |
Although there was lesser incidence of poor APGAR score, Meconium stained liquor, admissions to NICU in cases of Oligohydramnios, but in almost 43% of cases, Oligohydramnios was associated with Low Birth Weight and there was higher rates of induction and increased number of caesarean deliveries. However long term effects were not studied.
In this study, isolated oligohydramnios was associated with Low birth weight babies and increased rates of induction and caesarean deliveries.
Conclusion
Determination of AFI is one of the important methods in antepartum fetal surveillance. It helps to identify fetuses at risk of poor perinatal outcome.
AFI determination is a valuable screening test that has got a sensitivity of 71%, specificity of 58% and negative predictive value of 82% and positive predictive value of 43%.
Oligohydramnios in obstetrics is a frequent occurrence and it points towards intensive surveillance and proper antenatal and postnatal care. Due to associated perinatal morbidity and mortality, incidence of induction and Caesarean section increase. However vaginal delivery has similar outcome, but strict vigilance in labour is mandatory. The long term outcomes have not been studied in this study. Oligohydramnios is significantly associated with IUGR and Low birth weight. So timely intervention by an obstetrician will be of help in improving the perinatal outcome.
