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ORIGINAL ARTICLE
Year : 2021  |  Volume : 24  |  Issue : 12  |  Page : 1793-1799

Comparative analysis of umbilical artery doppler indices of normal and suspected IUGR fetuses in the third trimester


1 Department of Radiation Medicine, Faculty of Medical Sciences, College of Medicine, University of Nigeria Ituku-Ozalla Campus, Enugu, Nigeria
2 Department of Radiation Medicine, University of Nigeria Teaching Hospital, Ituku-Ozalla, Enugu, Nigeria

Date of Submission30-Jan-2018
Date of Acceptance11-Jun-2021
Date of Web Publication09-Dec-2021

Correspondence Address:
Dr. A O Nnamani
Department of Radiation Medicine, Faculty of Medical Sciences, College of Medicine, University of Nigeria, Ituku-Ozalla Campus, Enugu
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njcp.njcp_46_18

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   Abstract 


Background: Intrauterine growth restriction (IUGR) is an important cause of perinatal morbidity and mortality, the prevalence of which is six times higher in developing countries. The sequelae of IUGR extend into adulthood with higher risk of neurodegenerative diseases for the patients. Umbilical artery (UA) Doppler is an affordable and noninvasive tool for predicting perinatal outcome in IUGR pregnancies. Aims: The objective of this study is to compare the predictive ability of UA Doppler ultrasonography in discriminating normal from growth-restricted pregnancies and to find out if there is any relationship between antenatal Doppler indices and perinatal outcomes. Patients and Methods: This is a cross-sectional study including 100 normal and 100 IUGR-suspected pregnancies, respectively. Each participant had a third trimester UA Doppler scan. Data were analyzed using SPSS version 18.0 (PASW Statistics for Windows, Version 18.0, Chicago: SPSS Inc.). Means were compared using Student's t-test and ANOVA. Tests of relationship and prediction were done using linear regression analysis and receiver operating characteristics. P ≤ 0.05 was considered statistically significant. Results: As pregnancy advanced, the mean values of UA Doppler indices decreased in normal and IUGR fetuses; however, they were significantly higher in the latter. UA systolic/diastolic (S/D) ratio showed the highest sensitivity (0.80) and specificity (0.91) for predicting IUGR compared to PI and RI. Cutoff values for PI, RI, and S/D ratio were 0.93, 0.67, and 2.93, respectively. Conclusion: IUGR fetuses had higher UA flow velocimetric indices compared with normal fetuses. UA Doppler study is highly sensitive in the prediction of IUGR.

Keywords: Doppler indices, IUGR, perinatal mortality, umbilical artery


How to cite this article:
Nnamani A O, Ibewuike C U, Okere P C, Obikili E N. Comparative analysis of umbilical artery doppler indices of normal and suspected IUGR fetuses in the third trimester. Niger J Clin Pract 2021;24:1793-9

How to cite this URL:
Nnamani A O, Ibewuike C U, Okere P C, Obikili E N. Comparative analysis of umbilical artery doppler indices of normal and suspected IUGR fetuses in the third trimester. Niger J Clin Pract [serial online] 2021 [cited 2022 Jan 25];24:1793-9. Available from: https://www.njcponline.com/text.asp?2021/24/12/1793/332081




   Introduction Top


Intrauterine growth restriction (IUGR) is the pathological failure of a fetus to attain its genetically determined potential size.[1],[2] A higher incidence of IUGR has been recorded in developing (6–30%) than developed countries (2–5%).[2],[3],[4] IUGR and small-for-gestational age (SGA) are related but not synonymous. SGA is a heterogeneous group of fetuses with birth weight below 10th percentile for age, who may be growth restricted due to impaired placentation, fetal anomalies or environmental causes, or constitutionally small but are perfectly healthy requiring minimal monitoring and routine antenatal care.[5],[6],[7] Therefore, the diagnosis of growth-restricted fetus and instituting appropriate management has become of paramount importance and reduces perinatal mortality.[8] The fetal umbilical artery (UA) provides a site of velocimetric studies as Doppler indices—pulsatility index (PI), resistive index, and systolic/diastolic (S/D) ratio evaluates the impedance to the flow through them. An abnormal UA Doppler is therefore an indicator of fetal peripheral vasoconstriction, hence reduced fetal oxygenation. UA Doppler study therefore helps in identifying a compromised fetus, thus reducing adverse perinatal outcomes including mortality.

While UA Doppler velocimetry has been rigorously evaluated and frequently used as a noninvasive test in the more developed climes, there is a dearth of local data on its application in the assessment of high-risk pregnancies including IUGR. This study aims to compare the predictive ability of UA Doppler ultrasonography in discriminating normal from growth-restricted pregnancies and to find out if there is any relationship between antenatal Doppler indices and perinatal outcomes.


   Materials and Methods Top


This is a prospective cross-sectional study which included age and gestational age-matched 100 women with IUGR-suspected pregnancies (case group) and 100 normal pregnant women (control group) attending antenatal clinic at a tertiary health institution in Enugu, southeast Nigeria. Ethical clearance was obtained from Health Research and Ethics Committee of University of Nigeria Teaching Hospital Ituku/Ozalla, Enugu State, Nigeria. Uncomplicated singleton pregnancies at 28–40-week gestational age dated by early ultrasound scan were included in control group. The case group included pregnant women with fetal ultrasound-estimated birth weight below the 10th percentile for gestational age and had known maternal or fetal risk factors for IUGR. Pregnant women with complications of pregnancy such as gestational diabetes, pre-eclampsia, antepartum hemorrhage, or medical illnesses such as chronic hypertension, diabetes mellitus, and renal disease were excluded from normal pregnancy group while women who had multiple gestation, antenatal diagnosis of congenital fetal anomalies, or refused to give consent were excluded from both groups. All subjects included in the study had early obstetric scans on or before 20 weeks of gestation. Demographic, clinical data, and fetal biometric measurements were collected and recorded. UA Doppler study was done by a sonologist with 6 years' experience, using a 3.5–5.0-MHz convex transducer on a portable Sonosite M-Turbo (Sonosite Inc., 2012) ultrasound machine using standard protocols [Figure 1]a and [Figure 1]b. The free portion of the umbilical cord was localized about 5 cm from its insertion into the fetal abdomen and the two umbilical arteries and one vein identified. The Doppler mode on the ultrasound machine was selected; wall filter was set as low as 50–100 Hz and sample volume was within the range of 2 mm over the artery. UA Doppler measurements were obtained in the absence of fetal movement and breathing. When the signal was steady, the waveform was frozen, the peak systolic and end-diastolic velocities were identified with cursors. Three waves were analyzed and these Doppler indices PI, RI, and S/D ratio automatically generated on the monitor. Doppler waveform indices were calculated from the maximum velocity waveform with the following computerized planimetry: PI = (peak systolic velocity − end-diastolic velocity)/time-averaged maximum velocity, RI = (peak systolic velocity − end-diastolic velocity)/peak systolic velocity, and S/D ratio = peak systolic velocity/end-diastolic velocity.[9] The mean of three measurements was recorded for each Doppler index.
Figure 1: (a) Trans-abdominal obstetric ultrasound in the third trimester showing A—umbilical arteries, V—umbilical vein, AF—amniotic fluid, PL—placenta; (b) trans-abdominal pulsed-wave Doppler ultrasound of the umbilical artery in the third trimester of pregnancy. The arrow indicates the umbilical artery, PL = placenta and AF = amniotic fluid

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The postnatal data collected from labor ward records included duration of admission in neonatal intensive care unit (NICU) and perinatal mortality.

Statistical analysis

The data collected were analyzed using Statistical Package for the Social Sciences (SPSS) version 18.0 (SPSS Inc. Released 2009, PASW Statistics for Windows, Version 18.0, Chicago: SPSS Inc.). The means of continuous variables were compared using Student's t-test and ANOVA. Tests of relationship and prediction were done using linear regression analysis and receiver operating characteristics (ROC). P ≤ 0.05 was considered as statistically significant.


   Results Top


The study included a total of 200 females of reproductive age group 18–44 years who were scanned in the third trimester. The mean gestational age in the control group was 32.24 weeks and in the case group was 32.40 weeks. There was no significant difference between the mean parity of both groups (control was 1.33, SD = 1.36 and case group, it was 1.42, SD = 1.31). The mean Doppler indices in the case group were PI = 0.91 ± 0.15, RI = 0.61 ± 0.06, and S/D ratio = 2.62 ± 0.41 and PI = 0.85 ± 0.09, RI = 0.58 ± 0.07, and S/D ratio = 2.42 ± 0.41 in the control group [Table 1]. All the Doppler indices of the case group were significantly higher than the control group of the same gestational age (P < 0.00). The Doppler values in both groups decreased with increase in gestational age [Figure 2] and [Figure 3]. A significantly higher perinatal mortality rate was recorded among the pregnancies suspected of IUGR (10%) than among the control group (2.0%) [Table 2]. The mean values of the Doppler indices PI, RI, and S/D ratio were significantly higher in the fetuses that died (1.13 ± 0.17, 0.70 ± 0.05, and 3.26 ± 0.43, respectively) than the fetuses that lived (0.88 ± 0.12, 0.60 ± 0.06, and 2.55 ± 0.34, respectively) in the case group (P = 0.00) [Table 3]. A significant association was observed between perinatal mortality and all Doppler indices (P = 0.00) in the pregnancies suspected of IUGR but not in the control [Table 4] and [Table 5]. All the Doppler indices were significantly higher in fetuses that stayed longer in NICU [Table 6]. The S/D ratio with AUC value of 0.95 is the most accurate index in predicting bad perinatal outcome with the largest area under the curve [Table 7], [Figure 4]. The best cutoffs that maximize sensitivity and specificity for these indices is PI 0.99 [Table 8], RI 0.67 [Table 9], and S/D 2.93 [Table 10]. Umbilical Doppler indices equal to or above these cutoff values could signify bad perinatal outcome in pregnancies suspected of IUGR. Four subjects had abnormal Doppler indices. The managing obstetrician requested fortnightly UA Doppler scan of these gestations. Preterm Cesarean section delivery of these fetuses and longer stay at newborn intensive care unit were noted in the postnatal period.
Table 1: Mean values of Doppler indices of umbilical artery in normal pregnancies and pregnancies suspected of IUGR

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Figure 2: The Doppler indices in normal pregnancies. PI, RI, and S/D ratio gradually decrease with advancing gestational age

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Table 2: Frequency of perinatal mortality among the pregnancies suspected of IUGR and normal pregnancies

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Figure 3 : Graph showing the Doppler indices in pregnancies suspected of IUGR. PI, RI, S/D ratio also decrease with advancing gestational age. However the indices are significantly higher than values obtained in normal pregnancies.

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Table 3: The means of Doppler indices by the perinatal mortality in the pregnancies suspected of IUGR

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Table 4: Association of Doppler indices with perinatal mortality in normal pregnancies

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Table 5: Association of Doppler indices with perinatal mortality in pregnancies suspected of IUGR

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Table 6: Comparison of mean of Doppler indices with duration of NICU stay

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Table 7: The accuracy of PI, RI, and S/D ratio as predictor of bad perinatal outcome

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Figure 4 : ROC curve demonstrating the sensitivity and specificity of the Doppler indices.

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Table 8: Data showing the sensitivity and specificity at various cutoff points of pulsatility index as indictors of bad perinatal outcome in IUGR

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Table 9: Data showing the sensitivity and specificity at various cutoff points of resistive index as indicators of bad perinatal outcome in IUGR

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Table 10: Data showing the sensitivity and specificity at various cutoff points of systolic/diastolic velocity ratio as indicators of bad perinatal outcome in IUGR

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   Discussion Top


Early detection of abnormality in high-risk pregnancies before any permanent damage occurs is the main aim of antenatal care. Doppler evaluation has been described by several authors as a reliable noninvasive predictor of adverse perinatal outcomes in high-risk pregnancies.[10],[11],[12] In the present study, there is no statistical difference between the mean age of control group and of the case group. Majority of the pregnant women were multiparous in case group. This differs from the finding of Olusanya[3] which showed that IUGR fetuses were likely to be delivered by primiparous teenage mothers. This study shows higher S/D ratio, pulsatility, and resistive indices in subjects with pregnancies suspected of IUGR than normal pregnancies which confirms the state of high resistance in umbilical arteries in cases of placental insufficiency. This finding tallies with the works of Bibi et al.[13] and Hamayel et al.,[14] which found higher Doppler indices in the SGA fetuses and fetuses of pre-eclamptic subjects when compared with normal pregnancies. In our study, the mean values of PI and RI were 0.81 ± 0.12 and 0.56 ± 0.07 in normal pregnancies and 0.91 ± 0.15 and 0.61 ± 0.06 in pregnancies suspected of IUGR, respectively. These are comparable to the data of Bibi et al.,[13] who found that the mean UA PI and RI were 0.97 ± 0.18 and 0.64 ± 0.08 in normal pregnancies and 1.24 ± 0.17 and 0.74 ± 0.08 in fetuses of pre-eclamptic mothers.

In normal pregnancies, as placental growth continues there is increase in the number of tertiary stem villi and small arterial channels. This causes a drop in vascular resistance in UA, which is seen as an increase in end-diastolic flow and resultant decrease in Doppler indices as gestation progresses. Our study showed a gradual decrease of PI, RI, and S/D ratio with increasing gestational age. A number of studies have also reported same.[2],[14],[15],[16],[17]

We found that S/D ratio decreased with advancing gestational age in normal pregnancies, which reflects the decrease placental flow resistance. The mean S/D ratios at 30 and 37 weeks of gestation were 2.39 and 2.31, respectively. This was similar to the findings of Acharya et al.,[16] who reported mean S/D ratio of 2.83 and 2.34 at 30 and 37 weeks, respectively, and Ayoola et al.,[2] who reported S/D ratio of less than 3 after 30 weeks of gestation in normal pregnancies. In our study, the mean values of PI and RI at 30 and 37 weeks were 0.84, 0.79 and 0.60, 0.56, respectively. Comparable data had been reported by Ayoola et al.,[2] Acharya et al.,[16] and Paudel et al.[9] They reported mean PI in the range of 0.95–0.99 and 0.80–0.86 and mean RI in the range of 0.63–0.65 and 0.56–0.60 at 30 and 37 weeks, respectively.

The mean values of the PI, RI, and S/D ratio in our study were significantly higher in the fetuses that died than the fetuses that lived in the case group. Other studies have shown that perinatal morbidity and mortality are also greater in fetuses with abnormal UA Doppler studies.[16],[18],[19]

When the accuracy of UA PI, RI, and S/D ratio in predicting perinatal outcome was analyzed using ROC curve, S/D ratio was the most accurate Doppler index which predicted perinatal outcome. Trudinger et al.[19] reached this same conclusion when he reported that the diagnostic efficacy of umbilical arterial S/D ratio in high-risk pregnancy appeared to be more sensitive, but less specific than non-stress test in predicting fetal growth restriction and fetal distress. However, differing Adekanmi et al.[20] asserted that UA PI is the most accurate index in predicting perinatal outcome.

Our study established a valuable cutoff of PI, RI, and S/D ratio for prediction of the effects of IUGR. The Doppler ultrasonography is considered to be positive for risk of uteroplacental insufficiency, if the UA Doppler indices were above the cutoff level and negative if they were below the cutoff. PI lower than 0.985 and/or RI lower than 0.665 and/or S/D ratio lower than 2.925 had negative predictive value of 98% for diagnosing IUGR. This implies that if a pregnant woman has a negative result (values lower than the cutoffs), the clinician can be 98% confident that the fetus is not at risk of IUGR. This is similar to the findings of Bibi et al.,[13] who reported cutoff values of 0.98 and/or 0.64 for PI and RI, respectively, were associated with 100% sensitivity and higher specificity to rule out preeclampsia rather than confirm it.


   Conclusion Top


Pregnancies suspected of IUGR have higher UA flow velocimetry compared with normal pregnancies. Growth-restricted fetuses with normal UA flow velocimetry are at a lower risk than those with abnormal velocimetry in terms of perinatal mortality and neonatal intensive care admission.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

1.
McMaster Fay R. Intrauterine growth restriction: Recent developments, definitions and future research. Clin Obstet Gynecol Reprod Med 2019;5:1-3.  Back to cited text no. 1
    
2.
Ayoola OO, Bulus P, Loto OM, Idowu BM. Normogram of umbilical artery Doppler indices in singleton pregnancies in South-western Nigerian women. J Obstet Gynaecol Res 2016;42:1694-8.  Back to cited text no. 2
    
3.
Olusanya BO. Intrauterine growth restriction in low income country. Risk factors, adverse perinatal outcomes and correlation with current WHO multicenter growth reference. Early Hum Dev 2010;86:439-44.  Back to cited text no. 3
    
4.
Borna S, Nasrolahi S, Khansari S. The study of predictive value of uterine artery Doppler in incidence of Preeclampsia and intrauterine growth restrictions in pregnant women. Int J Women's Health Reprod Sci 2019;7:354-9.  Back to cited text no. 4
    
5.
Rajarajeswari R, Thendral V. Prediction of perinatal outcome with umbilical artery Doppler in IUGR fetuses- A prospective analytical study in a tertiary medical college in TamilNadu, India. Int J Reprod Contracept Obstet Gynecol 2017;6:1098.  Back to cited text no. 5
    
6.
Taimur S, Nida S, Sanna F, Nida H, Syed A, Maqbool Q. Intrauterine growth retardation- Small events, big consequences. Ital J Pediatr 2011;37:41.  Back to cited text no. 6
    
7.
Akolekar R, Syngelaki A, Gallo DM, Poon LC, Nicolaides KH. Umbilical and fetal middle cerebral artery Doppler at 35 37 weeks' gestation in the prediction of adverse perinatal outcome. Ultrasound Obstet Gynecol, 2015;46:82-92.  Back to cited text no. 7
    
8.
Patange RP, Goel N. Role of colour doppler: Cerebral and umbilical arterial blood flow velocity in normal and growth restricted pregnancy. J Evol Med Dent Sci 2014;3:3310-20.  Back to cited text no. 8
    
9.
Paudel S, Lohani B, Gurung G, Ansari MA, Kayastha P. Reference values for Doppler indices of the umbilical and fetal middle cerebral arteries in uncomplicated third trimester pregnancy. J Inst Med 2010;32:5-13.  Back to cited text no. 9
    
10.
Udo DU, Igbinedion BO, Akhigbe A, Enabudosoe E. Assessment of uterine and umbilical arteries Doppler indices in third trimester pregnancy-induced hypertension in UBTH, Benin-city. Niger Med Pract 2017;71:3-4.  Back to cited text no. 10
    
11.
Munikumari T, Vijetha V, Sree Divya NV. Comparison of diagnostic efficacy of umbilical artery and middle cerebral artery waveform with color Doppler study for detection of intrauterine growth restriction fetuses. Int J Contemp Med Surg Radiol 2017;2:41-6.  Back to cited text no. 11
    
12.
Mirza N, Meena V, Garg R, Gupta V, Iqbal R, Meena K, et al. Comparison of non stress test and umbilical artery doppler in high risk pregnancy. Int J Med Sci Educ 2017;4:131-7.  Back to cited text no. 12
    
13.
Bibi S, Shahin N, Babak M, Nouzar N. Screening utility of umbilical artery Doppler indices in patients with preeclampsia. Iran J Reprod Med 2010;8:167-72.  Back to cited text no. 13
    
14.
Hamayal NA, Baghlaf H, Blakemore K, Crino JP, Burd I. Significance of abnormal umbilicalartery doppler studies in normally grown fetuses. Matern Health Neonatol Perinatol 2020;6:1.  Back to cited text no. 14
    
15.
Srikumar S, Debnath J, Ravikumar R, Bandhu HC, Maurya VK. Doppler indices of the umbilical and fetal middle cerebral artery at 18-40 weeks of normal gestation: A pilot study. Med J Armed Forces India 2017;73:232-41.  Back to cited text no. 15
    
16.
Acharya G, Wilsgaard T, Berntsen GK, Maltau JM, Kiserud T. Doppler indices in the second half of pregnancy. Am J Obstet Gynecol 2005;192:937-44.  Back to cited text no. 16
    
17.
Chanprapaph P, Wanaeirak C, Tongsong T. Umbilical artery doppler waveform indices in normal pregnancy. Thai J Obstet Gynaecol 2000;12:103-7.  Back to cited text no. 17
    
18.
Ganju S, Dhiman B, Sood N. Correlation of abnormal umbilical artery Doppler indices and mode of delivery in intrauterine growth restriction. Trop J Obstet Gynaecol 2019;36:403-7.  Back to cited text no. 18
  [Full text]  
19.
Trudinger BJ, Cook CM, Giles WB, Ng S, Fong E, Connelly A, et al. Fetal umbilical artery velocity waveforms and subsequent neonatal outcome. Br J Obst Gynecol 1991;98:378-84.  Back to cited text no. 19
    
20.
Adekanmi AJ, Roberts A, Akinmoladun JA, Adeyinka AO. Uterine and umbilical artery Doppler in women with pre-eclampsia and their pregnancy outcomes. Niger Postgrad Med J 2019;26:106-12.  Back to cited text no. 20
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