A case-control investigation of foetal outcome in a case of oligohydramnios after 34 weeks of pregnancy

Aim: To evaluate the fetal outcome in a case of oligohydramnios after 34 weeks of pregnancy. Materials and methods: A prospective case control study was conducted in the Department of obstetrics and gynaecology, VIMS, Pawapuri, Nalanda, Bihar, India, for 18 months. 100 antenatal cases with >34 weeks of gestation with AFI ≤5 cm by sonographic estimation were included as study group and 100 women with normal AFI (8-24 cm) were included as control group. Induction of labour was done for women with high risk factors like PIH, by PGE 2 gel and accelerated with oxytocin. Labour outcome of the women were recorded includes, spontaneous /induced, nature of A F, FHR tracings, mode of delivery, indication for cesarean section or instrumental delivery. Perinatal findings such as APGAR score <7 at 1 mt and 5 mt, birth weight, admission to NICU, perinatal morbidity and mortality were noted. Results: Study group consists of 48 % Gr 1, 52 % Gr 2 and above and control group 52% Gr 1, 48% Gr 2 and above (Chi square=21.59, p<0.0001). Antenatal complications were not seen in 70% in the study group and 58% in control group. The AFI in study and control groups. In the study group 70% of women had AFI below 4. The nature of the amniotic fluid was clear in 30% in study and 80% in control group. Amniotic fluid was thin meconium stained in 31% in study, 15% in control group and was thick meconium stained in 40% in study and 10% in control group (Chi square=21.57, p<0.0001). Incidence of LSCS in the study group was 55% and 19% in control group. Percentage of birth weight of babies in study and control group is shown in Table 5. Birth weight <2.5 kg was found in 60% in study group and 18% in control group with mean of 2.3 and 2.9 in study and control group respectively (p <0.001) statistically significant. Conclusion: To conclude in presence of oligohydramnios a thorough evaluation for hypertension, PIH, diabetes PROM etc. should be done. An AFI ≤5 cm detected after 28 weeks was associated with adverse pregnancy outcome and poor perinatal outcome. Determination of AFI should be used as an adjunct to other fetal surveillance methods and is a valuable test for predicting fetal distress in labour requiring cesarean delivery. Introduction Oligohydramnios is described as a condition with decreased amniotic fluid volume relative to gestational age. The amniotic fluid (AF) is a part of the baby’s life support system. Amniotic fluid is produced soon after the amniotic sac is formed at about 12 days after conception. It is first made up of effusion that is provided by the mother's circulation and then around the 20th weeks fetal urine becomes the primary substance. If the measurement of AF is too low it is called oligohydramnios. If the measurement of AF is too high it is called polyhydramnios. Oligohydramnios was defined as Amniotic fluid index (AFI) ≤5 (or less than the 5th percentile) or the absence of a pocket measuring at least 2 × 1 cm. With the help of method of amniotic European Journal of Molecular & Clinical Medicine (EJMCM) ISSN: 2515-8260 Volume 07, Issue 09, 2020 3823 fluid estimation by AFI using four quadrant techniques during transabdominal USG, as per described by Phelan et al in 1997, better identification of fetus at high risk can be done. Oligohydramnios is a common complication of pregnancy and the incidence of this is reported to be around 1 to 5 % of total pregnancies. The accurate diagnosis of oligohydramnios has become possible by ultrasonographic examination during pregnancy It can occur at any time during pregnancy, but it is most common during the last trimester. Amniotic fluid levels decrease by half once a pregnant patient reaches 42 weeks gestation. Oligohydramnios can complicate 12% of pregnancies that go past 41 weeks. Usually the degree of Oligohydramnios is proportional to the severity of placental hypo perfusion and IUGR (Intra Uterine Growth Restriction). The most likely cause of oligohydramnios in IUGR babies is decreased urine output. There are numerous maternal and fetal risk factors associated with a reduction of AFI. Decreased amount of amniotic fluid, particularly in third trimester, has been associated with multiple fetal risks like cord compression, musculoskeletal abnormalities such as facial distortion and clubfoot, intrauterine growth restriction, low birth weight, fetal distress in labour, meconium aspiration syndrome, severe birth asphyxia, low APGAR scores, NICU admission, congenital abnormities and stillbirths. The sequel from long standing oligohydramnios includes pulmonary hypoplasia, potter’s syndrome, club foot and hand and hip dislocation. However, some studies done in cases of abnormal liquor volume show that amniotic fluid index is a poor predictor of adverse outcome. Early detection of oligohydramnios and its management may help in reduction of perinatal morbidity and mortality on one side and decreased caesarean deliveries on the other side. The findings of oligohydramnios can be associated with congenital fetal abnormalities, premature rupture of membranes, uteroplacental insufficiency, growth retardation, post datism, chronic abruptio placentae, maternal illness i.e. hypertension, preeclampsia, abnormalities of twinning, history of drug intake etc. Preeclampsia, Intrauterine Growth Restriction (IUGR) and post-dated pregnancies are the commonest causes. Materials and methods A prospective case control study was conducted in the Department of obstetrics and gynaecology, VIMS, Pawapuri, Nalanda, Bihar, India, India for 18 months, after taking the approval of the protocol review committee and institutional ethics committee. Methodology 100 antenatal cases with >34 weeks of gestation with AFI ≤5 cm by sonographic estimation were included as study group and 100 women with normal AFI (8-24 cm) were included as control group. Detailed history was taken and clinical examination was done for all cases. Clinical evidence of oligohydramnios was looked for and previous obstetric and USG reports were reviewed. Only those women who remembered their last menstrual period correctly with previous 3 regular cycles and dating scan were included for the study. USG was done for all women and AFI was calculated by 4 quadrant Amniotic Fluid measurement technique. Women with gestational age <34 weeks and >42 weeks, polyhydramnios, PROM, multiple gestation, IUD, mal presentations, placenta previa, congenital anomalies were excluded from the study. Induction of labour was done for women with high risk factors like PIH, by PGE 2 gel and accelerated with oxytocin. Spontaneous onset was allowed for women with no risk factors along with twice a week NST and weekly Biophysical profile (BPP). All cases were monitored thro continuous fetal monitoring during labour. After ARM nature of AF noted. Those who European Journal of Molecular & Clinical Medicine (EJMCM) ISSN: 2515-8260 Volume 07, Issue 09, 2020 3824 developed significant variable deceleration/ late decelerations, with or without meconium stained liquor were delivered by cesarean section. All newborn babies were seen by pediatrician. Labour outcome of the women were recorded includes, spontaneous /induced, nature of A F, FHR tracings, mode of delivery, indication for cesarean section or instrumental delivery. Perinatal findings such as APGAR score <7 at 1 mt and 5 mt, birth weight, admission to NICU, perinatal morbidity and mortality were noted. Results Study group consists of 48 % Group 1, 52 % Group 2 and above and control group 52% Group 1, 48% Group 2 and above (Chi square=21.59, p<0.0001). Antenatal complications were not seen in 70% in the study group and 58% in control group. Mild pre-eclampsia was seen in 11% in study group and 22% in control group. Severe pre-eclampsia was present in 21% in study group and 11% in control group. Anemia was seen in 10% in control group women only. Table 1 showing the AFI in study and control groups. In the study group 70% of women had AFI below 4. Table 1: Amniotic fluid index in study and control group AFI Study group number % AFI Control group number % 2 -3 35 35 8.1-11 40 40 3.1-4 35 35 11.1-14 35 35 4.1-5 30 30 14.1-17 25 25