This is the current release of the guideline.

This guideline updates a previous version: Zelop CM, Andreotti RF, Lee SI, DeJesus Allison SO, Bennett GL, Brown DL, Glanc P, Horrow MM, Javitt MC, Lev-Toaff AS, Podrasky AE, Scoutt LM, Expert Panel on Women's Imaging. ACR Appropriateness Criteria® growth disturbances -- risk of intrauterine growth restriction. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 6 p. [24 references]

The appropriateness criteria are reviewed biennially and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

Intrauterine growth restriction (IUGR)

To evaluate the appropriateness of radiologic procedures for pregnant women at risk of intrauterine growth restriction (IUGR)

Pregnant women with a risk of intrauterine growth restriction (IUGR)

Utility of radiologic examinations in differential diagnosis

Literature Search Procedure

The Medline literature search is based on keywords provided by the topic author. The two general classes of keywords are those related to the condition (e.g., ankle pain, fever) and those that describe the diagnostic or therapeutic intervention of interest (e.g., mammography, MRI).

The search terms and parameters are manipulated to produce the most relevant, current evidence to address the American College of Radiology Appropriateness Criteria (ACR AC) topic being reviewed or developed. Combining the clinical conditions and diagnostic modalities or therapeutic procedures narrows the search to be relevant to the topic. Exploding the term "diagnostic imaging" captures relevant results for diagnostic topics.

The following criteria/limits are used in the searches.

1. Articles that have abstracts available and are concerned with humans.
2. Restrict the search to the year prior to the last topic update or in some cases the author of the topic may specify which year range to use in the search. For new topics, the year range is restricted to the last 5 years unless the topic author provides other instructions.
3. May restrict the search to Adults only or Pediatrics only.
4. Articles consisting of only summaries or case reports are often excluded from final results.

The search strategy may be revised to improve the output as needed.

The total number of source documents identified as the result of the literature search is not known.

Strength of Evidence Key

Category 1 - The conclusions of the study are valid and strongly supported by study design, analysis, and results.

Category 2 - The conclusions of the study are likely valid, but study design does not permit certainty.

Category 3 - The conclusions of the study may be valid, but the evidence supporting the conclusions is inconclusive or equivocal.

Category 4 - The conclusions of the study may not be valid because the evidence may not be reliable given the study design or analysis.

The topic author drafts or revises the narrative text summarizing the evidence found in the literature. American College of Radiology (ACR) staff draft an evidence table based on the analysis of the selected literature. These tables rate the strength of the evidence for all articles included in the narrative text.

The expert panel reviews the narrative text, evidence table, and the supporting literature for each of the topic-variant combinations and assigns an appropriateness rating for each procedure listed in the table. Each individual panel member forms his/her own opinion based on his/her interpretation of the available evidence.

More information about the evidence table development process can be found in the ACR Appropriateness Criteria® Evidence Table Development document (see the "Availability of Companion Documents" field).

Modified Delphi Technique

The appropriateness ratings for each of the procedures included in the Appropriateness Criteria topics are determined using a modified Delphi methodology. A series of surveys are conducted to elicit each panelist's expert interpretation of the evidence, based on the available data, regarding the appropriateness of an imaging or therapeutic procedure for a specific clinical scenario. American College of Radiology (ACR) staff distributes surveys to the panelists along with the evidence table and narrative. Each panelist interprets the available evidence and rates each procedure. The surveys are completed by panelists without consulting other panelists. The ratings are a scale between 1 and 9, which is further divided into three categories: 1, 2, or 3 is defined as "usually not appropriate"; 4, 5, or 6 is defined as "may be appropriate"; and 7, 8, or 9 is defined as "usually appropriate." Each panel member assigns one rating for each procedure per survey round. The surveys are collected and the results are tabulated, de-identified and redistributed after each round. A maximum of three rounds are conducted. The modified Delphi technique enables each panelist to express individual interpretations of the evidence and his or her expert opinion without excessive bias from fellow panelists in a simple, standardized and economical process.

Consensus among the panel members must be achieved to determine the final rating for each procedure. Consensus is defined as eighty percent (80%) agreement within a rating category. The final rating is determined by the median of all the ratings once consensus has been reached. Up to three rating rounds are conducted to achieve consensus.

If consensus is not reached, the panel is convened by conference call. The strengths and weaknesses of each imaging procedure that has not reached consensus are discussed and a final rating is proposed. If the panelists on the call agree, the rating is accepted as the panel's consensus. The document is circulated to all the panelists to make the final determination. If consensus cannot be reached on the call or when the document is circulated, "No consensus" appears in the rating column and the reasons for this decision are added to the comment sections.

Not applicable

A formal cost analysis was not performed and published cost analyses were not reviewed.

Criteria developed by the Expert Panels are reviewed by the American College of Radiology (ACR) Committee on Appropriateness Criteria.

ACR Appropriateness Criteria®

Clinical Condition: Growth Disturbances—Risk of Intrauterine Growth Restriction (IUGR)

Variant 1: Risk of IUGR initial evaluation.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 2: Small fetus, low or low normal fluid, follow-up studies.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 3: Normal sized fetus, low or absent fluid, follow-up studies.

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Summary of Literature Review

Intrauterine growth restriction (IUGR) is an important complication of pregnancy. It can be associated with significant risks of perinatal morbidity and mortality. One of the primary mechanisms of IUGR is uteroplacental insufficiency, which may occur in a variety of maternal or placental conditions. The major concern in IUGR is not the small size of the fetus, per se, but the possibility of life-threatening fetal compromise. IGUR is usually characterized as a small-for-gestational-age (SGA) fetus whose estimated fetal weight (EFW) is below the 10th percentile for that gestational age according to a reference population. However, some SGA fetuses are constitutionally small and not jeopardized by unfavorable placental health. Some growth-restricted fetuses may measure at or above the 10%, yet still be compromised by suboptimal rate of growth.

When clinically suspected, IUGR can be confirmed as probably present by sonographic fetal measurements and weight estimation, but both false-negative and false-positive cases can be anticipated. Findings that should prompt an ultrasound (US) examination include maternal size smaller than dates (lag of the fundal height on physical examination of >3 cm) or otherwise anticipated from a prior US, poor maternal weight gain, maternal hypertension, or pre-eclampsia. Other maternal conditions such as lupus erythematosus or a history of previous birth of a growth-restricted infant may also warrant evaluation.

The greater the risk of IUGR based on the clinical findings, the greater is the positive predictive value of US, but the likelihood of IUGR also increases even when US predicts a normal weight, and the risk of IUGR persists when the clinical suspicion is high even when US does not detect a fetus with an EFW less than the 10th percentile. EFW and abdominal circumference are equivalently better than the ratio between femur length and abdominal circumference in predicting IUGR, and biometry performed within 2 weeks of delivery is more predictive than when performed at 26 to 34 weeks. One group of researchers found that among SGA fetuses with no anatomic abnormalities, only those that were asymmetric (abdomen small in proportion to head) were associated with increased pregnancy-induced maternal hypertension before 32 weeks and cesarean delivery for abnormal heart rate patterns compared with those of fetuses average for gestational age (AGA). Additionally, asymmetric SGA fetuses sustained more adverse neonatal composite outcomes compared to symmetric SGA or AGA fetuses.

Once a probability of IUGR has been established, and uteroplacental insufficiency is considered to be a likely mechanism based on US findings and clinical setting, there are a series of possible therapeutic interventions that can be used to improve fetal growth and try to prevent fetal compromise. Assessment of fetal well-being is essential to the management of such pregnancies. This testing is aimed at determining if there is life-threatening fetal compromise, and whether urgent premature delivery would offer a better chance of survival and avoidance of morbidity than would continued exposure to an increasingly hostile intrauterine environment.

Periodic fetal biometry, evaluation of amniotic fluid volume, use of the biophysical profile (BPP) or a selected subset of its component tests, Doppler US, fetal heart-rate monitoring, and fetal movement counting can all contribute to the determination of fetal compensation or compromise. It is beyond the scope of this guideline to compare these methods and rate the relative effectiveness of the many individual parameters testable alone or in various combinations. Instead, the guideline ranks the relative utility of these broad categories of fetal assessment once a risk of IUGR and potential fetal compromise has been established.

Biophysical Profile

The BPP has been and remains the mainstay of fetal well-being evaluation. It consists of four parameters variably sensitive to the acute exposure of the fetus to hypoxemia: fetal breathing movements, fetal limb and body movements, fetal tone, and amniotic fluid volume as an indicator of chronic hypoxemia. The nonstress test (NST), which is sometimes included with the BPP as a fifth component, can be used alone as a test of acute status, but it is often coupled with amniotic fluid measurement, a valuable reflection of fetal hypoxemic exposure over the previous week. Each of the four or five components of the BPP receives a score of 0 or 2, hence, a maximum score of eight (or 10). Scores of 8 to 10 on the BPP are strong indicators of a well-compensated fetus, but there are many false positives when the fetus fails one or two of the acute marker tests. Reduced amniotic fluid volume is an important predictor of intrapartum fetal distress, much of which is attributable to umbilical cord compression events, and the fluid volume should be periodically checked in pregnancies suspected to have IUGR. Testing strategies usually evaluate one or more of the fetal well-being parameters at least weekly, and often twice weekly, from the point of potential postnatal viability onward. Amniotic fluid is usually assessed weekly, but more often if it is approaching severely low levels. Daily or even more frequent testing by BPP or NST may be indicated in critical situations.

Doppler Evaluation

Extensive research on Doppler analysis of uterine, umbilical, and various intrafetal vessels confirms a strong correlation between high-resistance arterial waveform patterns (e.g., low, absent, or reversed diastolic flow in the umbilical artery) and subsequent IUGR, hypoxemic fetal morbidity, and mortality. The correlation is greatest in high-risk pregnancies but insufficiently predictive in general, low-risk populations to be useful as a primary screening test.

Some have argued that since Doppler US appears to be applicable primarily in a population already defined as high risk, the clinical decisions as to when a fetus is compromised and requires emergent delivery will be based on the BPP and heart-rate monitoring, making the Doppler assessment superfluous. A meta-analysis of 20 controlled trials of Doppler ultrasonography, however, found "compelling evidence" that knowledge of the Doppler evaluation findings improved perinatal outcome in high-risk pregnancies, reducing antenatal admissions, inductions of labor, and cesarean sections for fetal distress, and reducing the odds of perinatal death by 38%.

Studies correlating Doppler evaluation findings with the BPP, amniotic fluid volume, NST, US fetal weight estimates, and maternal blood pressure have shown that predictabilities of IUGR and fetal compromise are, to some extent, additive. Doppler waveform abnormalities may precede clinical recognition of less-than-expected abdominal enlargement, with abnormal BPP an even later finding. One review summarizes many of these concepts about the sonographic assessment of IUGR. Another research group found that decreased amniotic fluid and abnormal umbilical cord arterial Doppler waveforms were independent predictors of poor neonatal outcomes. A retrospective study found that SGA singleton pregnancies with abnormal umbilical artery blood flow patterns had higher cesarean section rates for fetal nonreassuring status, increased neonatal intensive care unit stays, and increased neonatal morbidity. Those SGA fetuses with normal umbilical Doppler patterns were unassociated with these complications, suggesting that these were constitutionally small babies rather than being growth-restricted. As the degree of fetal compromise progresses, there is a transition from a high-resistance middle cerebral artery (MCA) Doppler pattern to a low-resistance pattern, so-called cephalization of blood flow to protect the brain.

In addition to arterial Doppler evaluation, the fetal venous system can also be interrogated as a surrogate for forward cardiac blood flow or preserved cardiac output. In a recent study of fetuses with early-onset placental dysfunction, research demonstrated that ductus venous Doppler parameters emerge as the primary cardiovascular factor in predicting neonatal outcome.

Fetal Movement Counting

An additional test of value in IUGR and other high-risk pregnancies is daily (or even more frequent) fetal movement counting by the mother. Frequent and vigorous fetal movements are evidence of well-being, providing reassurance to the mother, while diminishing fetal activity can provide an early warning of a deteriorating fetal status. The testing is easy and inexpensive but provides benefit in addition to the formal fetal surveillance protocols.

The specific variant conditions included in this Appropriateness Criteria® topic require several additional comments.

A fetus small for dates compared with an earlier US study in which amniotic fluid volume was low or low normal is the typical setting in which uteroplacental insufficiency is the most likely mechanism for IUGR. Repeat US for biometry is indicated, with the frequency adjusted by the severity of the growth restriction and the gestational age. Mild growth lag prior to 28 to 30 weeks can be remeasured in 4 weeks, while severe IUGR after 33 weeks may be best remeasured in 2 weeks. Some formal testing protocol for fetal well-being should be initiated on a weekly or twice-weekly schedule. Daily fetal movement counts are indicated.

IUGR caused by uteroplacental insufficiency is unusual when a normal amniotic fluid volume is present with a small or very small fetus. A first consideration should be the possibility of inaccurate dating of the pregnancy. This can be confirmed by follow-up US biometry that demonstrates appropriate interval growth of the fetal measurement parameters for the number of weeks intervening between the first and second examination. With a symmetrically very small fetus for dates, however, particularly if detected in the second or even first trimester, the possibility of aneuploidy, especially trisomy 18, trisomy 13, and triploidy, must be considered. Needless to say, the presence of fetal anomalies will raise the concern for chromosomal abnormality considerably. Diagnosis is generally accomplished by amniocentesis, but if a rapid karyotype is needed (e.g., to avoid a cesarean section because of fetal compromise of a fetus with a lethal condition), cordocentesis or placental biopsy can often provide an answer in 48 to 72 hours. FISH (fluorescent in situ hybridization) from amniocentesis is first line with cordocentesis and placental biopsy as other options.

When there is low or absent amniotic fluid with a normally grown fetus, causes of oligohydramnios other than IUGR must be considered. These include obstruction or nonfunction of the fetal urinary tract, premature rupture of membranes, and tocolysis of preterm labor by nonsteroidal anti-inflammatory agents. Regardless of its etiology, oligohydramnios is an important risk factor for perinatal morbidity and mortality, due largely to umbilical cord compression but also, in cases of early and long-standing oligohydramnios, to the possible occurrence of pulmonary hypoplasia. Close monitoring of fetal condition is indicated along with periodic imaging evaluation of the fetus to check growth and chest configuration for degree of lung compression.

Safety Issues

Ultrasound

US is generally considered safe during pregnancy. As in any imaging procedure, the ALARA (as low as reasonably achievable) principle should be followed. Cardiac activity may be documented in real time, or M-mode imaging. Because of higher energy levels, spectral and color Doppler evaluation of the embryo during the first trimester should be avoided if possible. Spectral and color Doppler evaluation may be extremely useful for other first trimester issues, including retained products of conception and adnexal masses.

Summary

• IUGR, with its inherent risks of fetal morbidity and mortality from the hypoxemia of inadequate uteroplacental function, must be considered a major abnormality of pregnancy.
• When it is suspected on the basis of clinical and sonographic findings, urgent management decisions may be necessary, including the possibility of emergent preterm delivery.
• A protocol of frequent fetal surveillance is indicated to guide patient management and the timing of delivery.

Abbreviations

• BPP, biophysical profile
• IUGR, intrauterine growth restriction
• US, ultrasound

Relative Radiation Level Designations

Relative Radiation Level*	Adult Effective Dose Estimate Range	Pediatric Effective Dose Estimate Range
O	0 mSv	0 mSv
	<0.1 mSv	<0.03 mSv
	0.1-1 mSv	0.03-0.3 mSv
	1-10 mSv	0.3-3 mSv
	10-30 mSv	3-10 mSv
	30-100 mSv	10-30 mSv
*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as NS (not specified).

An algorithm for growth disturbances/growth restriction is provided in Appendix 2 of the original guideline document.

The recommendations are based on analysis of the current literature and expert panel consensus.

The American College of Radiology (ACR) Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists, and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient's clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those examinations generally used for evaluation of the patient's condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the U.S. Food and Drug Administration (FDA) have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

The American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panel on Women's Imaging

Panel Members: Carolyn M. Zelop, MD (Principal Author); Rochelle F. Andreotti, MD (Panel Chair); Susanna I. Lee, MD, PhD (Panel Vice-chair); Sandra O. DeJesus Allison, MD; Genevieve L. Bennett, MD; Douglas L. Brown, MD; Theodore Dubinsky, MD; Phyllis Glanc, MD; Donald G. Mitchell, MD; Ann E. Podrasky, MD; Thomas D. Shipp, MD; Cary Lynn Siegel, MD; Jade J. Wong-You-Cheong, MD

Not stated

This is the current release of the guideline.

This guideline updates a previous version: Zelop CM, Andreotti RF, Lee SI, DeJesus Allison SO, Bennett GL, Brown DL, Glanc P, Horrow MM, Javitt MC, Lev-Toaff AS, Podrasky AE, Scoutt LM, Expert Panel on Women's Imaging. ACR Appropriateness Criteria® growth disturbances -- risk of intrauterine growth restriction. [online publication]. Reston (VA): American College of Radiology (ACR); 2008. 6 p. [24 references]

The appropriateness criteria are reviewed biennially and updated by the panels as needed, depending on introduction of new and highly significant scientific evidence.

Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.

Print copies: Available from the American College of Radiology, 1891 Preston White Drive, Reston, VA 20191. Telephone: (703) 648-8900.

The following are available:

• ACR Appropriateness Criteria®. Overview. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.
• ACR Appropriateness Criteria®. Literature search process. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Evidence table development. Reston (VA): American College of Radiology; 4 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Radiation dose assessment introduction. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.

None available

This summary was completed by ECRI on June 28, 2002. The information was verified by the guideline developer on October 1, 2002. This summary was updated on March 24, 2006. This NGC summary was updated by ECRI Institute on December 14, 2007. This NGC summary was updated by ECRI Institute on June 16, 2010. This NGC summary was updated by ECRI Institute on August 31, 2011.

Instructions for downloading, use, and reproduction of the American College of Radiology (ACR) Appropriateness Criteria® may be found on the ACR Web site .