Dr. Anita Kant is the Head of the Department at Asian Institute of Medical Sciences, Faridabad, since 2010. She did her postgraduation degree from MGIMS, Sewagram, and has been practicing since 1984. She has 25 publications to her credit in various national journals.
Objectives: To evaluate the cerebroplacental ratio which is the ratio of pulsatility index of fetal middle cerebral and umbilical arteries, in normal and high-risk pregnancies during 30–36 weeks of gestation.
Methods: In this study, we included 70 patients, who were scanned for Doppler parameters of Middle cerebral artery and Umbilical artery pulsatility index ratio of fetus, between 30 and 36 weeks, and then were followed till delivery. Thirty-five patients with normal pregnancy and 35 patients with high-risk pregnancy were included. Perinatal outcome was evaluated in relation to indices ratio.
Results: There was cerebroplacental ratio of\1.00 in eight cases of the study group in comparison with the control group in which there is no case of < 1.00 value. It was associated with poor perinatal outcome in terms of need for lower segment cesarean section for fetal distress, Apgar < 8 at 5 min, and admission to nursery.
Conclusion: Cerebroplacental ratio is highly sensitive in diagnosing hemodynamically compromised fetuses and very useful for the prediction of adverse perinatal outcome in these fetuses.
Keywords : Intrauterine growth retardation, Pulsatility index (PI), Middle cerebral artery (MCA), Umbilical artery (UA)
Doppler is a noninvasive method for evaluation of fetoplacental circulation without any disturbance to human pregnancy.
It gives valuable information about hemodynamic situation of the fetus and is an efficient diagnostic test of fetal jeopardy that helps in management of high-risk pregnancy [1].
The use of doppler can be credited leading to a significant decrease in perinatal mortality and morbidity. The color Doppler ultrasound gives us information directly on vascular resistance and indirectly on blood flow. The present study had been planned to measure cerebroplacental ratio in predicting perinatal outcome.
In this study, we evaluated the cerebroplacental ratio which is the ratio of pulsatility index of fetal middle cerebral and umbilical arteries, in normal and high-risk pregnancies during 30–36 weeks of gestation.
It was a prospective study, which included 70 patients (with informed consent), who were scanned for Doppler parameters between 30 and 36 weeks and then were followed up till delivery: 35 patients with normal pregnancy (control group) and 35 patients with high-risk pregnancy (study group).
Inclusion Criteria (High-Risk Pregnancy)
1. Singleton pregnancy.
2. The gestational age of patient should be between 30 and 36 weeks.
3. At least one of the following risk factors was present in the study group patient:
• Gestational hypertension
• Essential hypertension
• Prior neonatal death
• Diabetes mellitus
• Malnutrition
• Anemia
Exclusion Criteria
(a) Multiple pregnancy
(b) Congenital anomalies in the fetus.
Obstetrics color Doppler was done on pregnant women (between 30 and 36 weeks) who attended the Obstetrics OPD/IPD at Asian Institute of Medical Sciences, Faridabad, between February 2014 and June 2015. Due approval was taken from ethics committee.
Complete evaluation of all patients was done in the following format:
Detailed clinical history
General and systemic examination
Color Doppler USG evaluation.
Recordings from the umbilical artery (UA) were obtained by placing the sample volume in the lumen of the artery away from the placental and fetal cord insertion. After recording a technically satisfactory Doppler waveform, the pulsatility index (PI) and S/D ratio were noted.
Recordings from the middle cerebral artery (MCA) were obtained on a transverse section of fetal head, at the level of the thalami and cavum waveform, and pulsatility index and S/D ratio were noted.
Cerebroplacental Ratio [2–8] 5 PI of MCA/PI of UA
Outcome was calculated as:
(a) Perinatal outcome:
In terms of birth weight, Apgar score, admission to
NICU, and days of stay in NICU.
(b) Obstetrical outcome:
In terms of mode of delivery.
In the control group, one patient (2.9%) had umbilical artery velocimetry PI ratio [1.42, while 34 (97.1%) had umbilical artery velocimetry PI ratio B1.42, and in the study group, six patients (17.1%) had umbilical artery velocimetry PI ratio above the gestational-age-specific cutoff value and 29 (82.9%) had umbilical artery PI ratio below the gestational-age-specific cutoff value. The difference between two groups was not statistically significant (Table 1).
In the control group, nine (25.7%) patients had PI ratio < 1.5, 26 (74.3%) patients had PI ratio C1.5 percentile, while in the study group, only 14 (40.0%) had PI ratio below the gestational-age-specific cutoff value and 21 (60.0%) had PI ratio above the gestational-age-specific cutoff value. The difference between two groups was not statistically significant. According to ROC curve, AUC 0.606 and SD 0.068 and 95% CI 0.472–0.739 (Table 2).
Table 3 shows MCA/UA PI ratio in the study population using a single cutoff value of 1.00. No patient (0.00%) in the control group had MCA PI/UA PI ratio < 1.00, i.e., all of the patients (100.0%) had the ratio value more than the cutoff value. However, eight (22.9%) patients in the study group had MCA/UA PI ratio < 1.00 and 27 (77.1%) had C1.00. Difference between two groups was statistically significant.
The outcomes were divided into major and minor groups (Table 4). In the control group, there were no stillbirth, two NICU admission, four premature birth, no post-natal complication, five delivered by LSCS due to fetal distress. In the study group, there was no stillbirth, five cases were in need of ventilator, 14 had NICU admission, 28 had premature birth, 10 had respiratory distress syndrome, five had necrotizing enterocolitis, 15 had cesarean section due to fetal distress, and three had Apgar score < 8.
As shown in Table 5, among all the Doppler indices evaluated, MCA/UA PI < 1.0 showed the highest sensitivity (57.14%), the highest negative predictive value (70.0%), the highest specificity (100.0%), and the positive predictive value (100.0%) in the prediction of overall perinatal outcome.
The use of Doppler ultrasound in high-risk pregnancies appears to improve obstetric outcomes and is a promising tool in reducing prenatal deaths. Fetuses with abnormal Doppler velocimetry had a significantly higher incidence of preterm birth, low birth weight, and admission to NICU (Table 6).
In the present study, MCA/UA PI ratio with a single cutoff value < 1.00 has achieved high specificity and positive predictive value of 100.0 and 100.0% each with relatively low sensitivity.
Maged et al. [9] in their study concluded that late-onset SGA fetuses with normal Doppler velocimetry on diagnosis show progression from 37 weeks gestation with worsening cerebroplacental ratio followed by a decrease in MCA PI.
Various studies have noticed a similar poor neonatal outcome in fetuses with abnormal Doppler velocimetry. Our study revalidates the findings. There were more number of cesarean sections and NICU admissions in abnormal Doppler indices in various studies; in the present study, 24 cases out of 35 high-risk pregnancies had cesarean section—15 for fetal distress—and 16 babies required NICU admissions. Predictive value of Doppler for fetal outcome is shown in Table 5, which differs in various studies
Despite the differences in observations between various authors based on different study designs, all these studies have common observations which are noteworthy:
1. Higher specificity is obtained by using the ratio (MCA/
UA PI) in the prediction of intrauterine growth
retardation.
2. High negative predictive values in prediction of major
adverse perinatal outcome.
Compliance with Ethical Standards
Conflict of interest The authors have no conflict of interest.
Ethical Standard The research is in compliance with ethical standard. Permission has been taken and is approved by institutional ethical committee.
Informed Consent Informed consent was obtained from all patients for being included in the study.
