1. What are the benefits of Fetal Renal Artery Doppler, Middle Cerebral Artery Doppler and Ductus Venosus Doppler in pregnancies complicated by Intrauterine Growth Restriction? A Systematic Review Protocol
Ms Christina Preen, 1 Associate Professor Zachary Munn2
1MClinSc Candidate, The Joanna Briggs Institute, Faculty of Health Science, The University of Adelaide, SA 5005
2 The Joanna Briggs Institute, Faculty of Health Science, The University of Adelaide, SA 5005
2. Objective
4. Methods
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Globally pregnant women undergo ultrasound examinations to assess fetal well-being and growth. ¹ Ultrasound uses sound waves to produce diagnostic images of body structures. Ultrasound can also assess the presence and speed of blood flow within structures and vessels using Doppler ultrasound ¹.
Second trimester ‘screening’ morphology ultrasound scans assess all major fetal anatomical structures including the brain, spine, heart, limbs and fetal kidneys. ¹ Healthy women with no comorbidities and a ‘normal’ ultrasound result require no further scans. However, many pregnancies include complications such as intrauterine growth restriction (IUGR) which require surveillance ultrasounds.
Intrauterine Growth Restriction is an important issue due to its associated perinatal mortality3 but it is also a predisposing factor for late onset disease processes such as hypertension, cardiovascular and diabetes mellitus in adulthood.10 In the literature there are varying levels of evidence regarding management of Intrauterine Growth restriction, including the benefits of ultrasound surveillance scans, and affiliated Doppler parameters, adding
to the issues associated with looking after these complicated patients.
1. Background
The objective of this systematic review is to identify, evaluate and synthesise the available evidence for the advantages of using Fetal Renal Artery Doppler, Middle Cerebral Artery Doppler and Ductus Venosus Doppler in those pregnancies complicated by intrauterine growth restriction.
Type of Participant
The Systematic review will consider studies that include pregnancies complicated by Intrauterine Growth Restriction (IUGR).
Type of Intervention
This review will consider studies that evaluate the use of Fetal Renal Artery Dopplers, Middle Cerebral Artery Dopplers, Ductus Venosus Dopplers with Umbilical Artery Dopplers in a setting of suspected IUGR.
Type of Comparators
Standard care including Umbilical Artery Dopplers
Types of Outcomes
This review will consider studies that include any of the following outcome measures: stillbirth, neonatal death, fetal acidosis,induction of labour, caesarean section, perinatal death.
Types of Studies
This review will consider experimental studies, including randomised controlled trials, non-randomised controlled trials, and quasi-experimental studies, prospective and retrospective cohort studies, case control studies and cross sectional studies.
Pregnancy Complications Pregnancy Complications include: smoking, obesity, gestational diabetes, placental insufficiency and intrauterine growth restriction (IUGR). Intrauterine growth restriction is defined as the estimated fetal weight (EFW) plotting at <10th percentile for gestation.3,4,5 IUGR is the single greatest risk factor for stillbirth amongst normal fetuses³.
Intrauterine Growth Restriction (IUGR) - Ultrasound Fetuses at risk of IUGR require additional third trimester ultrasound scans. Parameters include fetal biometry, amniotic fluid volume, visualization of fetal stomach, bladder and kidneys¹ and Doppler assessment of umbilical arteries; additional Doppler measurements are employed for fetuses suspected of exhibiting the so-called ‘fetal brain sparing’ phenomenon. 4,6.
Fetal Brain Sparing Fetuses suffering from IUGR may be hypoxic; A feature of IUGR is ‘brain sparing’ whereby a fetus preferentially shunts blood flow to critical organs such as the brain, heart and adrenal glands, at the expense of other structures including the fetal kidneys;4,5.
5. Methodological Quality
Papers selected for retrieval will be assessed by two independent reviews for methodological validity prior to inclusion in the review using standardised critical appraisal instruments from the Joanna Briggs Institute SUMMARI.
6. Data Collection
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Data will be extracted from papers included in the review using the standardised data extraction tool from JBI-SUMMARI and they will be pooled in a statistical meta-analysis using the same tool.
3. Search Strategy
The search strategy will involve a three step process. An initial limited search of PubMed and CINAHL will be undertaken followed by an analysis of keywords contained in the titles and abstracts. A second search with all identified key words will be undertaken across PubMed, CINAHL, Embase & Cochrane Central Trials Register. Thirdly, reference lists of retrieved studies will be assessed for suitability.
References
1 Curry, RA & Tempkin BB. Sonography: Introduction to Normal Structure and Function, 2nd edn, Saunders, Missouri.
2 Vlajkovic, S, Vasovic, L, Dakovic-Bjelakovic, M & Cukuranovic R. Age-related Changes of the Human Fetal Kidney Size, Cells Tissues Organs, 2004, no.182, pp
3 Baird, SM, Davies-Tuck, M Coombs, P, Knight, M & Wallace EM. Detection of the growth-restricted fetus: which centile charts? 2006, Sonography, vol. 3, no. 3, pp
4 Silver, Lori E, Decamps, Phillipe J, Korst, Lisa M, Platt, Lawrence D, & Castro, Lony C. Intrauterine growth restriction is accompanied by decreased renal volume in the human fetus, 2003, Am J Obstet Gynecol, vol. 188, no. 5, pp
5 Ismail, Hamizah & Chang, Yao-Lung. Sequelae of Fetal Growth Restriction,’ 2012, Journal of Medical Ultrasound, vol. 20, pp
6 Giussani, Dino A. The fetal brain sparing response to hypoxia: physiological mechanisms, 2015, J Physiol, pp
7 El Behery, MM, Ibraheim, MA, Siam, S & Seksaka, MA. ‘Fetal Renal Volume and Fetal Doppler in Normal and Growth Restricted Fetuses: Is there a correlation?’ 2012, Gynecol Obstet, vol. 2, no. 2:118. doi: /
8 Ratnaparkhi, CR, Kurve, SA, Mitra, KJ, Onkar, PM, Kulkarni, AM & Kant, DM. ‘Correlation between fenal renal volume and fetal renal Doppler in normal and growth restricted fetuses: an initial experience,’ 2015, J of Evolution of Med and Dent Sci, vol. 4, no. 4, issue 63, pp
9 Verburg, BO, Geelhoed, JJM, Steegers, EAP, Hofman, A, Holl, HA, Witteman, JCM & Jaddoe WW. ‘Fetal kidney volume and its association with growth and blood flow in fetal life: the generation R study,’ 2006, Int Soc Nephrol, no. 72, pp
10 Lumbers, ER, Yu, ZY, & Gibson KJ. ‘The Selfish Brain and The Barker Hypothesis,’ 2001, Clinical and Experimental Pharmacology and Physiology, no.28, pp
Pregnancy Complication Image: Health Mom & Baby, Pregnancy Complications, viewed 26/01/17.
Intrauterine Growth Restriction Image: Aliabadi T, ‘Intrauterine Growth Restriction,’ viewed 26/01/17.
Fetus in the womb image: 9 months in the womb: Real footage of a developing baby (fetus), video, YouTube June 1, 2015, viewed 23/01/17.
Acknowledgments
The author would like to acknowledge the following individuals for contributing their ideas and support for conducting this project: Associate Professor Zachary Munn.