Abstract
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)
Introduction
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.
Aims and Objectives
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.
Materials and Methods
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)
Singleton pregnancy.
The gestational age of patient should be between 30 and 36 weeks.
- 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
Multiple pregnancy
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] = PI of MCA/PI of UA
Outcome was calculated as:
-
Perinatal outcome:
In terms of birth weight, Apgar score, admission to NICU, and days of stay in NICU.
-
Obstetrical outcome:
In terms of mode of delivery.
Results
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 ≤1.42, 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).
Table 1.
Umbilical artery velocimetry PI ratio in both groups with gestational-age-specific cutoff values
| UA PI | Controls | Cases | P value | ||
|---|---|---|---|---|---|
| Frequency | % | Frequency | % | ||
| ≤1.42 | 34 | 97.1 | 29 | 82.9 | 0.106 |
| >1.42 | 1 | 2.9 | 6 | 17.1 | |
| Total | 35 | 100 | 35 | 100 | |
P value = 0.106 (not significant)
In the control group, nine (25.7%) patients had PI ratio <1.5, 26 (74.3%) patients had PI ratio ≥1.5 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 2.
Middle cerebral artery (MCA) velocimetry PI ratio in both groups with gestational-age-specific cutoff values
| MCA PI | Controls | Cases | P value | ||
|---|---|---|---|---|---|
| Frequency | % | Frequency | % | ||
| ≥1.50 | 26 | 74.3 | 21 | 60.0 | 0.203 |
| <1.50 | 9 | 25.7 | 14 | 40.0 | |
| Total | 35 | 100 | 35 | 100 | |
P value = 0.203 (not significant)
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 ≥1.00. Difference between two groups was statistically significant.
Table 3.
MCA/UA PI ratio in both groups using a single cutoff value of 1.00
| MCA/UA PI | Controls | Cases | P value | ||
|---|---|---|---|---|---|
| No. of cases | % | No. of cases | % | ||
| >1 | 35 | 100.0 | 27 | 77.1 | 0.005 |
| <1 | 0 | 0.0 | 8 | 22.9 | |
| Total | 35 | 100 | 35 | 100 | |
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.
Table 4.
Adverse perinatal outcomes in both groups
| Adverse perinatal outcome indicatora | Control no. | Study no. | Total no. | P value | Si | |
|---|---|---|---|---|---|---|
| Major | ||||||
| 1 | Stillbirth | 0 | 0 | 0 | 0.0 | NS |
| 2 | Need of ventilator | 0 | 5 | 5 | 0.054 | NS |
| 3 | NICU stay >2 days | 2 | 14 | 16 | 0.001 | S |
| 4 | Premature birth | 4 | 24 | 28 | <0.001 | HS |
| 5 | RDS | 0 | 10 | 10 | <0.001 | HS |
| 6 | NEC | 0 | 5 | 5 | 0.054 | NS |
| Minor | ||||||
| 7 | LSCS for fetal distress | 5 | 15 | 20 | 0.008 | S |
| 8 | 5 min Apgar score <8 | 0 | 3 | 3 | 0.239 | NS |
Si significance, S significant, NS not significant, HS highly significant, NEC necrotising enterocolitis, RDS respiratory distress syndrome
aOne newborn can have more than one adverse outcome
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.
Table 5.
Adverse (major + minor) perinatal outcome of both groups according to Doppler indices: performance characteristics
| Criteria | Sensitivity | Specificity | Predictive value | Prevalence | |
|---|---|---|---|---|---|
| Positive | Negative | ||||
| UA PI >1.4 | 20.59 | 97.22 | 87.5 | 56.5 | 48.6 |
| MCA PI <1.5 | 48.57 | 73.9 | 73.9 | 61.7 | 50.0 |
| MCA/UA PI <1.0 | 57.14 | 100.0 | 100.0 | 70.0 | 52.0 |
Discussion
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).
Table 6.
Performance characteristics of MCA/UA ratio in the prediction of intrauterine growth retardation [2–8]
| Parameter assessed | Authors | Sensitivity | Specificity | Positive predictive value | Negative predictive value | Accuracy |
|---|---|---|---|---|---|---|
| Pulsatility index < 1.08 | Dhand et al. | 57 | 67 | 87 | 29 | – |
| Pulsatility index < 2SD | Rajesh and Agamya | 68.8 | 100 | 100 | 26.3 | – |
| Pulsatility index < 1.08 | Gramellini | 40 | 100 | 100 | 62.5 | 70 |
| Pulsatility index < 1.08 | Bano et al. | 44.4 | 100 | 100 | 64.3 | 72.2 |
| Pulsatility index < 1.00 | Present study | 22.9 | 100.0 | 100.0 | 56.5 | 61.4 |
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:
Higher specificity is obtained by using the ratio (MCA/UA PI) in the prediction of intrauterine growth retardation.
High negative predictive values in prediction of major adverse perinatal outcome.
Conclusion
For the prediction of adverse perinatal outcome in women with high-risk pregnancies, the best Doppler index, according to our work, is MCA/UA PI ratio. In cases with abnormal Doppler, timely interventions lead to improved perinatal outcome. Hence, repeated Doppler study in these indices will help to reduce perinatal morbidity and mortality in high-risk cases.
Ever since the introduction of Doppler technology, repetitive noninvasive hemodynamic monitoring in pregnancy has been a great help to improve perinatal outcome in complicated pregnancies. The Doppler patterns follow a longitudinal trend with early changes in the umbilical artery followed by middle cerebral artery and other peripheral arteries. Venous changes follow the arterial pattern and occur in severely compromised fetus and predict poor perinatal outcome.
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.
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.
Footnotes
Dr. Anita Kant MBBS, MS, FICOG, is Director and HOD in Asian Institute of Medical Sciences, Faridabad, Haryana; Dr. Namrata Seth MBBS, DGO, DNB, is Associate Consultant in Asian Institute of Medical Sciences, Faridabad, Haryana; Dr. Deepti Rastogi MBBS, DGO, is secondary DNB student in Asian Institute of Medical Sciences, Faridabad.
References
- 1.Malik R, Saxena A. Role of colour Doppler indices in the diagnosis of intrauterine growth retardation in high risk pregnancies. J Obstet Gynecol India. 2013;63(1):37. doi: 10.1007/s13224-012-0210-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Khanduri S, Parashari UC, Bashir S, et al. Comparison of diagnostic efficacy of umbilical artery and middle cerebral artery waveform with color Doppler study for detection of intrauterine growth restriction. J Obstet Gynecol India. 2013;63(4):249. doi: 10.1007/s13224-012-0326-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Morrissette MM. Abnormal fetal umbilical cord doppler? What should i Do next? A case study demonstrating corroboration of umbilical cord doppler and middle cerebral doppler. J Diagn Med Sonogr. 2012;28(4):179–182. doi: 10.1177/8756479312441503. [DOI] [Google Scholar]
- 4.Benavides-Serralde A, Scheier M, Cruz-Martinez R, et al. Changes in central and peripheral circulation in intrauterine growth-restricted fetuses at different stages of umbilical artery flow deterioration: new fetal cardiac and brain parameters. Gynecol Obster Investig. 2011;71(4):274–280. doi: 10.1159/000323548. [DOI] [PubMed] [Google Scholar]
- 5.Hernandez-Andrade E, Stampalija T, Figueras F. Cerebral blood flow studies in the diagnosis and management of intrauterine growth restriction. Curr Opin Obstet Gynecol. 2013;25(2):138–144. doi: 10.1097/GCO.0b013e32835e0e9c. [DOI] [PubMed] [Google Scholar]
- 6.Zhu MY, Milligan N, Keating S, et al. The hemodynamics of late-onset intrauterine growth restriction by MRI. Am J Obstet Gynecol. 2016;214(3):367.e1–367.e17. doi: 10.1016/j.ajog.2015.10.004. [DOI] [PubMed] [Google Scholar]
- 7.Mureşan D, Rotar IC, Stamatian F. The usefulness of fetal Doppler evaluation in early versus late onset intrauterine growth restriction. Review of the literature. Med Ultrason. 2016;18(1):103–109. doi: 10.11152/mu.2013.2066.181.dop. [DOI] [PubMed] [Google Scholar]
- 8.DeVore GR. The importance of the cerebroplacental ratio in the evaluation of fetal well-being in SGA and AGA fetuses. Am J Obstet Gynecol. 2015;213(1):5–15. doi: 10.1016/j.ajog.2015.05.024. [DOI] [PubMed] [Google Scholar]
- 9.Maged AM, Abdelhafez A, Mostafa WAI, et al. Fetal middle cerebral and umbilical artery Doppler after 40 weeks gestational age. J Matern Fetal Neonatal Med. 2014;27(18):1880–1885. doi: 10.3109/14767058.2014.892068. [DOI] [PubMed] [Google Scholar]