|Year : 2022 | Volume
| Issue : 1 | Page : 35-40
A study of fetal umbilical artery and middle cerebral artery doppler velocimetry before and after treatment of severe maternal iron deficiency anaemia
Suhail Rafiq1, Sheema Posh2, Saima Wani2, Shahnaz Tang3
1 Department of Radiodiagnosis and Imaging, GMC, Srinagar, Jammu and Kashmir, India
2 Department of Obstetrics and Gynaecology, SKIMS, Srinagar, Jammu and Kashmir, India
3 Department of Obstetrics and Gynaecology, L. D. Hospital, GMC, Srinagar, Jammu and Kashmir, India
|Date of Submission||15-Oct-2020|
|Date of Acceptance||29-Jul-2021|
|Date of Web Publication||18-Oct-2022|
Department of Obstetrics and Gynaecology, SKIMS, Srinagar, Jammu and Kashmir
Source of Support: None, Conflict of Interest: None
Background: Despite maternal iron deficiency anemia being a worldwide medical complication, very few studies have been performed to evaluate the efficacy of iron supplementations for treating and preventing adverse pregnancy sequelae. This study attempts to show the impact of maternal iron deficiency anemia on the mother and the fetus and whether treatment can reverse the physiological and pathological effects of anemia on the mother as well as the fetus. Objective: To evaluate the effect of vascular adaptation and extent of compensatory changes in the fetus with the change in maternal hemoglobin (Hb) levels and to study maternal and perinatal outcomes after treatment of maternal iron deficiency anemia. Methodology: The present study was an observational prospective study conducted on 50 pregnant women in GMC, Srinagar from January 2016 to June 2017. The study population was divided into two groups-Group A-Patients with moderate anemia – Hb 7–9 g/dl and Group B-Patients with severe anemia – Hb <7 g/dl. Group A received parenteral iron preparation and Group B received blood transfusion or packed red blood cells until Hb exceeded 7 g/dL, then parenteral iron was used. Maternal Hb and color Doppler were performed before and after treatment of anemia. Results: There was a decrease in the umbilical artery resistivity index (RI) after treatment of maternal anemia in both the groups and the decrease was more in those who received blood transfusion. There was an improvement in middle cerebral artery RI in both the groups after treatment and the increase was statistically significant. The C/U ratio was normalized to >1.1 in both the study groups after treatment of anemia. Conclusion: Our data support the fact that maternal Hb content of <7 g/dl is strongly associated with marked fetal hemodynamic adaptation and must be treated with acute red cell transfusion. Moderate anemia (>7 g/dl) is not sufficient to trigger fetal blood flow redistribution and can be treated with parenteral iron. Close monitoring of the fetal umbilical and cerebral circulation by Doppler examination in anemic pregnancies allows the measurement of the amplitude of fetal vascular response, early assessment of fetal damage and helps in improving fetal outcome as well.
Keywords: Anemia, Doppler ultrasound, fetal outcome, hemoglobin, maternal outcome
|How to cite this article:|
Rafiq S, Posh S, Wani S, Tang S. A study of fetal umbilical artery and middle cerebral artery doppler velocimetry before and after treatment of severe maternal iron deficiency anaemia. CHRISMED J Health Res 2022;9:35-40
|How to cite this URL:|
Rafiq S, Posh S, Wani S, Tang S. A study of fetal umbilical artery and middle cerebral artery doppler velocimetry before and after treatment of severe maternal iron deficiency anaemia. CHRISMED J Health Res [serial online] 2022 [cited 2022 Dec 8];9:35-40. Available from: https://www.cjhr.org/text.asp?2022/9/1/35/358813
| Introduction|| |
The WHO defines anemia in pregnant women as hemoglobin (Hb) level below 11 g/dl. The centers for disease control (CDC) (1998) has defined anemia in iron-supplemented pregnant women as Hb <11 g/dl in the first and third trimesters, and 10.5 g/dl in the second trimester. CDC recommends that Hb in pregnant women should not be allowed to fall <10.5 g/dl in the second trimester, taking into account the physiological changes of pregnancy.
According to the Indian Council of Medical Research, anemia is classified as:
- Mild: 9–10.9 g/dl
- Moderate: 7–9 g/dl
- Severe: <7 g/dl
- Very severe: <4 g/dl.
The effect of maternal anemia on the fetus and the newborn varies depending on the severity of anemia. Preterm birth, intrauterine growth restriction, neonatal anemia, and stillbirth are the possible fetal complications of anemia. Besides the severity of maternal anemia, the gestational period at which the fetus is exposed to low maternal Hb levels is also important in deciding the perinatal outcome.
Color Doppler ultrasound provides a convenient and effective method to assess the hemodynamic status of fetal circulation in relation to fetal hypoxia and thereby facilitates the monitoring of the fetus, prediction of adverse outcome, and thus, timely treatment to improve the survival prognosis of the fetus.
Distribution of fetal blood flow (between the placental and cerebral regions) is determined by middle cerebral artery (MCA) resistivity index (RI)/umbilical artery (UA) RI (C/U resistance ratio), which is the ratio between the cerebral resistance index (CRI) and umbilical resistance index (URI). This parameter is always >1.1 during normal pregnancy, but decreases in case of hypoxia because of the increase in URI (due to increase in placental resistance) and decrease in CRI (due to cerebral vasodilatation). At the same time, vasodilatation of the fetal MCA occurs resulting in the so-called “brain sparing effect” (compensatory flow or adaptation changes). These physiological adaptations have been demonstrated by changes in Doppler indices of the MCA.
As severe maternal anemia triggers a marked fetal cerebral vasodilatation, the Hb has to be recovered as soon as possible to suppress the cerebral vasodilatation. Moderate maternal anemia does not trigger fetal flow redistribution or abnormal fetal heart rate changes which suggest that fetal oxygenation remains satisfactory. This study attempts to show the impact of maternal iron deficiency anemia on the mother and the fetus and whether treatment can reverse the physiological and pathological effects of anemia on the mother as well as the fetus.
Fetal arterial Doppler
The volume of UA increases with advancing gestation hence the high vascular resistance detected in the first trimester gradually decreases. This decrease in vascular resistance allows a continuous forward blood flow in the UA throughout the cardiac cycle. The normal UA waveform usually has a “SAW-TOOTH” pattern with flow always in the forward direction. The impedance in UA is measured by RI which decreases from 0.756–0.609 in normal pregnancy. An abnormal waveform shows absent or reversed diastolic flow.
In pregnancies complicated by maternal anemia, there is the reduction in end-diastolic flow causing an increase in RI values followed by absent end-diastolic flow (RI = 1) and finally reversal of end-diastolic flow.
Middle cerebral artery
The cerebral circulation is normally a high impedance circulation with the continuous forward flow throughout the cardiac cycle. The MCA RI shows a biphasic trend with RI values being low in early as well as in late gestation due to the increased metabolic requirements of the brain during these periods. The normal value of MCA RI is 0.787 at 18 weeks, gradually increasing to 0.91 at 30 weeks. Thereafter, it again shows a falling trend and decreases to 0.785 at 40 weeks. In case of severe maternal anemia, there is an increase in end-diastolic flow which leads to a decrease in MCA-RI values.,,
C/U resistance ratio
The distribution of fetal blood flow is determined by the C/U resistance ratio, which is the ratio between the MCA RI and URI. This parameter is always >1.1 during normal pregnancy but decreases in case of anemia because the URI increases while the CRI decreases.
| Methodology and Study Design|| |
This prospective study was conducted on pregnant women attending the Postgraduate Department of Obstetrics and Gynaecology (Government Medical College and Associated Hospitals, Srinagar) for 18 months (from January 2016 to June 2017). The population consisted of 25 pregnancies with moderate anemia and 25 pregnancies that were complicated by severe anemia which were defined as under:
- Group A: Patients with moderate anemia – Hb 7–9 g/dl
- Group B: Patients with severe anemia – Hb <7 g/dl.
Doppler study of the umbilical, and fetal middle cerebral arteries was done which include:
- UA velocimetry (URI or UA RI)
- MCA velocimetry (MCA RI)
- MCA RI/UA RI also known as the C/U resistance ratio.
Maternal venous sample was taken for Hb level. The groups were managed accordingly:
Group (A): Received parenteral iron preparation after calculation of iron deficiency using the formula:
Total iron dose = Body weight × (Target Hb − Present Hb in g/dl) ×2.4 + 500 mg
(Iron sucrose in 500 cc saline over 1 h repeated every other day).
Group (B): Received blood transfusion or packed red blood cells until Hb exceeded 7 g/dL, then parenteral iron was used.
Maternal Hb level, iron profile, ultrasound, and color Doppler were repeated after completion of treatment. After delivery, APGAR score, neonatal intensive care unit admissions, preterm births, acute fetal distress (meconium staining), fetal growth restriction, and the number of perinatal deaths were assessed. The Doppler examination was done twice, i.e. on the day of admission day and after the completion of treatment.
Aims and objectives
- To evaluate the effect of maternal anemia on fetal condition in utero by color Doppler
- To study the maternal and perinatal outcome after treatment of maternal iron deficiency anemia.
- Women with gestational age > 26 weeks
- Women with singleton pregnancy
- Women with anemia (Hb < 10 g/dl).
- Women with age < 20 or > 35 years
- Women with dead fetus
- Women with multiple pregnancies
- Women with a history of recent blood transfusion
- Women with other vitamin deficiencies
- Women with cardiovascular diseases like cyanotic heart disease, heart failure, or pulmonary hypertension
- Women with infections and chronic inflammation.
Data have been statistically described in terms of:
- Mean ± standard deviation, for continuous variables
- Frequencies (number of cases) and percentages for categorical variables.
Comparison of numerical variables between the study groups was made using unpaired t-test and Chi-square test in comparing pre- and post-treatment values.
| Results|| |
- In our study, the age of patients ranged from 22 to 35 years of age with the maximum number of patients in 25–35 years age group. The mean age of patients was 29.56 + 3.09 years in Group A and 29.24 + 2.27 years in Group B [Table 1]
- The mean gestational age of our patients on admission was 35.6 + 1.80 weeks in Group A and 35.84 + 1.67 weeks in Group B which is almost the same in both the groups [Table 1]
- In the present study, most of the patients were primigravida in Group A and multigravida in Group B [Table 1]
- There was a significant increase in Hb levels in all patients after treatment of anemia[Table 2]
- There was a decrease in the UA RI after treatment of maternal anemia in both the groups and the decrease was more in those who received blood transfusion. A comparison for UA RI for both the groups before [Figure 1] and after treatment was statistically significant [P = 0.032 for Group A and P = 0.0001 for Group B; [Table 3]]
- There was an improvement in MCA RI in both the groups after treatment of anemia and the increase was statistically significant. A comparison was done in MCA RI [Figure 2] of patients in both the groups before [Figure 3] and after receiving treatment [Figure 4] for anemia. The P value for MCA RI before and after treatment of anemia in group A and Group B were 0.001 and 0.0001, respectively, i.e. statistically significant
- The C/U ratio was normalized to >1.1 in both the study groups after treatment of anemia. P value for C/U ratio in Group A and Group B before and after treatment of anemia was 0.653 (statistically insignificant) and 0.0001 (statistically significant), respectively [Figure 5]. After treatment of iron deficiency anemia, normalization of Doppler indices was observed. This suggests that color Doppler can be used for improving perinatal outcomes in maternal iron-deficiency anemia
- The majority of the patients delivered by normal vaginal delivery. In our study, 80% patients of Group A had vaginal delivery among which 64% had spontaneous delivery and in 20% of patients labor was induced. The remaining 20% of patients were delivered by cesarean section [Figure 6]. In Group (B), 76% of patients had vaginal delivery which included 44% spontaneous and 32% induced deliveries [Figure 7]
- The difference in APGAR score for the two groups was statistically insignificant [P > 0.05; [Table 4]]
- The percentage of fetuses with preterm births, fetal growth-restricted (FGR) and AFD was higher in those with severe maternal anemia [Table 5]. Preterm births occurred in 9 (36%) patients while as in Group B, they occurred in 8 (32%) patients with the difference between the two groups being statistically insignificant (P = 0.765). In Group A, FGR occurred in 2 (8%) babies and in Group B, 9 (36%) babies had FGR with the difference between the two groups being statistically significant (P = 0.016).In Group A, AFD was present in 3 (12%) babies and in Group B in 9 (36%) babies with the difference between the two groups being statistically significant (P = 0.046). In Group A, perinatal death was found in 1 (4%) patients while as in Group B, it was found in 6 (24%) patients with the difference between the two groups being statistically significant (P = 0.041).
|Figure 1: Color Doppler image with spectral waveform of umbilical artery showing high resistance flow with decreased diastolic flow|
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|Figure 2: Color Doppler image with spectral waveform of middle cerebral artery showing low resistance flow with increased diastolic flow (brain sparing)|
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|Figure 3: Continuous line diagram showing distribution of resistance index of middle cerebral artery before treatment|
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|Figure 4: Continuous line diagram showing distribution of resistance index of middle cerebral artery after treatment|
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|Figure 5: Double histogram showing distribution of C/U ratio before and after treatment along with change with treatment|
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| Discussion|| |
Maternal iron-deficiency anemia is a worldwide medical complication leading to adverse effects both in the mother as well as the fetus.
In this study, there is no correlation between the severity of maternal anemia with age, gestational age at admission, or delivery date. Our findings were similar to the study conducted by Stefanović et al. who reported that the maternal age and gestational age were similar in both moderate and severely anemic pregnant women. In our study, severe anemia affected primiparous women less than multiparous women. Similar findings were reported by Uche-Nwachi et al. There was a significant increase in Hb levels in all patients after treatment of anemia. Similar findings were reported by Stefanović et al.
There was a decrease in the UA RI after treatment of maternal anemia in both the groups and the decrease was more in those who received blood transfusion. These findings were consistent with those of Abdel Moiety and Ahmed. There was an increasing trend in MCA RI in both the groups after treatment and the increase was statistically significant. This was consistent with the study conducted by Stefanović et al. and Ancuta et al. who reported a similar decrease in MCA RI., The C/U ratio was normalized to >1.1 in both the study groups after treatment of anemia. Our observations were consistent with the findings of Stefanović et al. and Ancuta et al. who reported that the C/U ratio was restored to normal in both moderate and severely anemic patients after treatment., Our findings were also consistent with those of Abdel Moety and Ahmed.
Majority of patients in both groups delivered vaginally. This can be explained by the fact that a few of them had preterm births and vaginal delivery was preferred in anemic patients as blood loss is less in vaginal delivery as compared to cesarean section. These findings are similar to those of Chhabra et al. It was found that the APGAR score of newborns in Group B was less as compared to Group A in the gestational age of 33–36 weeks. Our findings were consistent with those of Abdel Moety and Ahmed who reported that low APGAR scores resolved in the majority of the fetuses after treatment of anemia and Goswami et al. reported an increased APGAR score in nonanemic patients as compared to anemic patients.,
The fetal prognosis was assessed in terms of the number of preterm births, FGR, AFD, and perinatal deaths. The percentage of fetuses with preterm births was higher in those with severe maternal anemia. Our findings were similar to those of Chhabra et al. and Jagadish Kumar et al., In our study, the risk of FGR increased with the increasing severity of anemia. Our findings were consistent with those of Chhabra et al. In our study, higher percentage of babies with AFD in severely anemic mothers was reported. These findings were in contrast with those of Sundaram and Murugesan who reported no significant association between maternal anemia and passage of meconium by the fetuses. Furthermore, the higher number of perinatal deaths were reported in severely anemic mothers. Similar findings were reported by Goswami et al. and Nair et al.,
| Conclusion|| |
Our data support the fact that maternal Hb content of <7 g/dl is strongly associated with marked fetal hemodynamic adaptation and must be treated with acute red cell transfusion. Moderate anemia (>7 g/dl) is not sufficient to trigger fetal blood flow redistribution and can be treated with parenteral iron. Close monitoring of the fetal umbilical and cerebral circulation by Doppler examination in anemic pregnancies allows the measurement of the amplitude of the fetal vascular response, early assessment of fetal damage and helps in improving fetal outcome as well.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]