The role of color doppler in high risk pregnancies: A prospective comparative study

Introduction

Fetal well-being is assessed in high risk pregnancies by a variety of methods which includes daily fetal movement count, biophysical profile and non stress test. These do not have a high degree of sensitivity and specificity.^[1] Doppler ultrasound informs about the hemodynamic status of fetus and gives an efficient diagnosis of fetal jeopardy which helps in management of high-risk pregnancies.^[2] Doppler scan is a cost effective and non invasive method to assess fetal well-being at an early stage even before physical changes in biophysical profile appear and thus is being hailed in modern obstetrics as one of the most important achievements.^[3]

“High risk pregnancies (HRPs) are defined as those pregnancies with preexisting or current conditions that put the mother, the fetus and the newborn baby at higher than normal risk for complications during or after the pregnancy and birth”.^[3]

Doppler provides an estimate of downstream placental vascular resistance and placental blood flow. A strong association between reduced end diastolic umbilical artery blood flow velocimetry and increased vascular resistance in the umbilical placental micro circulation leading to fetal acidosis has already been established.^[4]

Specifically an increased umbilical artery systolic/diastolic ratio is a risk factor for progression of fetal acidosis, fetal distress, preterm delivery, low Apgar scores and even perinatal deaths.^[4]

An obstetricain’s decision making improves to prevent intrauterine death as hypoxic cerebral damage begin before labor and intrapartum asphyxia is probably more damaging when superimposed on underlying hypoxia.^[5] Hence timely interventions can be taken.^[4] In cases of early diagnosis can be done which reduces the fetal morbidity and mortality.^[6] This technique studies the blood flow in the umbilical artery and MCA of fetus in the high-risk pregnancies especially those with preeclampsia gestational DM, IUGR.^[6]

The present study was aimed for the assessment of perinatal and maternal outcome in high-risk pregnancies.

Materials and Methods

The present study titled ‘The role of colour doppler in high risk pregnancies -A prospective comparative study’ was carried out at a tertiary care institute. 116 cases and 116 controls were recruited for the study after fulfilling inclusion and exclusion criteria.

Results

As per [Table 1] - total number of primigravida in cases were 76 (with maximum distribution among 18-25 years) and in controls were 75 (with maximum distribution among 18-25 years). Total number of multigravida in cases were 40 (with maximum distribution among 25-30 years) and in controls were 41 (with maximum distribution among 18-25 years).

As per [Table 2] cases and controls were divided according to high risk factors. Sickle cell trait/disease was the most common risk factor in cases(24%) and controls (25%).

According to [Table 3] cases and controls were divided according to gestational age. Maximum cases were of gestational age 34-36 weeks in cases and more than 36 weeks in controls.

According to [Table 4] cases and controls were divided according to mode of delivery. Maximum cases delivered by LSCS and maximum controls by vaginal delivery.

As per [Table 5] most common complication was need for blood products in both cases and controls.

As per [Table 6] babies of 50% cases and 45.6% controls had poor perinatal outcome. Among cases 28% had normal doppler and 21% had abnormal doppler.

As per [Table 7] babies of 20% cases and 30% controls needed NICU admission. Among those 20% cases 6% had normal doppler and 30% had abnormal doppler.

As per [Table 8] the most common doppler changes in cases of neonatal deaths was increased diastolic flow in middle cerebral artery, in macerated still born was absent end diastolic flow in umbilical artery and deranged CPR, in fresh still born was absent end diastolic flow in umbilical artery. Overall most commonly involved doppler change was absent end diastolic flow in umbilical artery.

Discussion

In our study, age range was from 17 to 38 years. 49.1% cases were in the age group of 18 to 25 years and 58% controls were in the age group 18 to 25 years. In the study by Upma Saxena, et al^[7] age ranged from 20-35 years with 65.33% women in the age group of 26-30 years with mean age of 28.53 years. In the study by Kavitha G et al.^[8] women were divided into two age groups 20-25 years (n=60) and 26-30 years (n=80). In our study majority of cases and controls were primigravida 65.5% and 64.6% respectively. In the study by Akhtar Ahmed et al.^[9] most of the cases were multigravida (64%). In the study by Messawa, et al.^[10] multipara women 85 (85%) were insignificantly high in group A than in group B. in both cases (72.4%) and controls(74.1%). In our study maximum numbers of cases and controls were found in the gestational age of more than 36 weeks. In cases(1.7%) the least numbers were found in the age group 31 to 32 weeks and in controls(1.7%) it was found in age group 32 to 34 weeks. In the study by Singh H et al^[11] maximum cases(37%) in the study group presented at gestational age between 34.1 and 37 weeks. Mean gestational age was 35.5 weeks for the study group. In the study by Akhtar Ahmed et al^[9] most of patients were more than 37 weeks of gestation. The most common high risk factor in cases and controls was AS/SS pattern. In the study by Singh H et al^[11] maximum cases were of PIH(20%), followed by anemia(15%) and pregnancy with Rh factor negative blood group (14%), BOH(8%). In the study by Urmila S, et al^[12] the most common risk factor found in the study group was PIH (44%) either alone (22%) or in combination with other risk factors like IUGR and BOH (22%). In our study most common mode of delivery was LSCS in cases and controls. In the study by Urmila S, et al.^[12] in the high risk group majority of the patients (78%) had LSCS (lower segment cesarean section) while in the control group most of the patients had vaginal delivery.

Out of 116 cases, there were 58(50%) perinatal deaths. Out of which 0.86% were neonatal deaths, 25.8% were fresh still births, 23.2% were macerated still births. Out of 116 controls, 53(45%) were perinatal deaths. Out of which 18.8% were neonatal deaths, 35.8% were fresh still births, 45.6% were macerated still births. The most common doppler finding here was deranged CPR (Cerebral placental ratio). In the study by Amin et al^[13] among 46 pregnancies with abnormal Doppler, the perinatal mortality and morbidity was 41.3% and 23.9%, respectively, as compared to patients with normal Doppler waveforms with 3.7% perinatal mortality and 11.1% morbidity. In the present study out of 116 cases 17.2% cases required NICU admission and 82.7% did not require NICU admission. In controls 25.8% required NICU admission and 74.8% did not require NICU admission. In our study it was found that, in patients with normal doppler 89.7% did not require NICU admission and 10.3% needed NICU admission. In patients with abnormal doppler 72.9% did not require NICU admission and 27.1% needed NICU admission. This was found to be statistically significant. Increased S/D in umbilical artery and AEDF showed maximum number of admissions. Association of high risk factors with NICU admissions was found to be statistically insignificant. In the study by Arduini and Rizzo^[2] 46.7% (56 of 120) of fetuses, there was at least one of the following adverse outcomes: perinatal deaths, cesarean delivery for fetal distress, asphyxia that necessitate admission to the neonatal intensive care unit for more than 48 hours.

In our study 0.8% cases and 8.6% controls had neonatal deaths. In this 1 case (0.8%) with abnormal doppler there was increased diastolic flow in MCA in a patient of overt DM. This baby had weight of 2.6kg and was delivered at a gestational age of 36 weeks. In the study by Mikovic et al.^[14] in the high risk group with abnormal Doppler indices, the average birth weight was 1327+ 245gm, neonatal mortality 8.6%, while perinatal mortality was 14.3%. Out of 48 cases with deranged doppler 9 had changes in uterine artery (7.7%), 4.3% had changes in umbilical artery, 5.17% had changes in MCA, 0.8% had changes in ductus venosus.

Conclusion

Thus, it is seen that abnormal obstetric umbilical artery velocimetry is a good predictor for predicting poor perinatal outcome like IUGR, NICU admissions, perinatal complications and even neonatal deaths. High risk pregnancies present a potential challenge for obstetricians for effective care to result in better maternal and perinatal outcome. Thus, doppler ultrasound can serve as a non-invasive, non-traumatic, and easily available diagnostic tool for antenatal monitoring of high risk pregnancies.

Source of Funding

None.

Conflict of Interest

None.