Guideline sources The following summarized guidelines for the evaluation and management of intrauterine growth restriction (IUGR) are prepared by our editorial team based on guidelines from the International Consensus Guideline (ICG 2023), the American College of Obstetricians and Gynecologists (ACOG 2021), the International Federation of Gynecology and Obstetrics (FIGO 2021), the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG 2020), the Society of Obstetricians and Gynaecologists of Canada (SOGC 2013), and the Royal College of Obstetricians and Gynaecologists (RCOG 2013). 1 2 3 4 5 6 Guidelines 1. Screening and diagnosis Indications for screening: As per FIGO 2021 guidelines, obtain risk stratification for fetal growth restriction (and other placenta-mediated complications) at the time of the first-trimester antenatal visit using history- https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 1/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway based (medical and obstetric) risk factors. B Show 5 more As per RCOG 2013 guidelines, assess all females for risk factors of small-for-gestational-age fetus/neonate to identify patients requiring increased surveillance. B As per SOGC 2013 guidelines, use accurate dating and obtain a review of the mother's menstrual history, relevant assisted reproductive technology information and either a first trimester or early second trimester dating ultrasound for effective screening of IUGR. A Show 6 more Diagnostic criteria: As per ICG 2023 guidelines, use national growth charts when available or carefully selected region- and ethnic-specific charts for accurate classification of small-for-gestational-age. A As per FIGO 2021 guidelines, define small-for-gestational-age as an estimated fetal weight or birth weight below the 10th percentile for gestational age. A Show 2 more As per ISUOG 2020 guidelines, do not use fetal size alone to identify fetal growth restriction unless abdominal circumference or estimated fetal weight is below the 3rd percentile. D Show 3 more As per SOGC 2013 guidelines, recognize that the definition of small-for-gestational-age for a fetus in utero is an estimated fetal weight measuring < 10th percentile on ultrasound. Recognize that this diagnosis does not necessarily imply pathologic growth abnormalities, and may simply describe a fetus at the lower end of the normal range. B Show 2 more 2. Diagnostic investigations History and physical examination: As per FIGO 2021 guidelines, elicit detailed history in patients with suspected fetal growth restriction. A As per RCOG 2013 guidelines, consider assessing fetal abdominal circumference or estimated fetal weight < 10th centile for the diagnosis of small-for-gestational-age fetus. B Show 5 more Fetal ultrasound: As per FIGO 2021 guidelines, confirm gestational age as the first step when fetal growth restriction is suspected. Use the first-trimester crown-rump length in the range of 7-60 mm as the most accurate method to date pregnancy, with the exception of pregnancies achieved by assisted reproductive technology. Use the earliest scan with a crown-rump length of at least 10 mm if more than one scan is obtained in the first trimester. A Show 5 more As per RCOG 2013 guidelines, obtain ultrasound measurement of fetal size in patients with a single symphysis fundal height plotting below the 10th centile or serial measurements https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 2/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway demonstrating slow or static growth by crossing centiles. B As per SOGC 2013 guidelines, consider obtaining fetal weight determination with abdominal circumference alone or in combination with head size (biparietal diameter or head circumference) and/or femur length to establish an estimated fetal weight. Recognize that fetal weight determination in fetuses between the 10th and 90th percentiles by ultrasound biometry alone has at least a 10% error rate across gestation. C Show 4 more Uterine artery Doppler ultrasound: As per ISUOG 2020 guidelines, consider obtaining Doppler velocimetry of the uteroplacental and fetoplacental circulations to distinguish between small-for-gestational-age and fetal growth restriction. E Show 2 more As per RCOG 2013 guidelines, refer for a detailed fetal anatomical survey and uterine artery Doppler by a fetal medicine specialist if severe small-for-gestational-age is identified at the 18- 20 week ultrasound. B Show 3 more Umbilical artery Doppler ultrasound: As per FIGO 2021 guidelines, obtain Doppler studies including at least the umbilical artery and, when available, also the uterine and middle cerebral arteries in patients with suspected fetal growth restriction. A As per ISUOG 2020 guidelines: Obtain fetal Doppler velocimetry both at the diagnosis of small-for-gestational-age and during follow-up. E Obtain fortnightly assessment of fetal growth and weekly assessment of umbilical artery- pulsatility index, middle cerebral artery-pulsatility index, cerebroplacental ratio and umbilicocerebral ratio in case of late small-for-gestational-age. E As per SOGC 2013 guidelines, obtain careful reevaluation of fetal anatomy and uterine and umbilical artery Doppler ultrasound. Recognize that determining whether IUGR is symmetric or asymmetric is of less clinical importance. A Show 4 more Fetal cardiotocography: As per ISUOG 2020 guidelines, assess the short-term variation as the main parameter when computerized cardiotocography is used. A As per RCOG 2013 guidelines: Do not obtain cardiotocography as the only form of surveillance in small-for-gestational-age fetuses. D Interpret cardiotocography based on short-term fetal HR variation from computerized analysis. A As per SOGC 2013 guidelines, do not obtain cardiotocography (non-stress testing) antenatally as a test of fetal well-being in isolation to monitor fetuses with IUGR. D https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 3/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway Screening for infections: As per FIGO 2021 guidelines: Obtain maternal screening for relevant congenital infections focusing on CMV and toxoplasmosis in patients with suspected fetal growth restriction. Consider screening for rubella, herpes, syphilis, malaria, and Zika virus in patients at high risk. A Obtain PCR tests for infectious agents during amniocentesis, when available, in patients with suspected fetal growth restriction, especially in cases with early-onset severe (estimated fetal weight < 3rd percentile) fetal growth restriction, in the presence of ultrasound findings associated with infectious etiologies, no obvious signs of placental dysfunction, and when the findings are likely to affect management. B As per RCOG 2013 guidelines: Obtain serological screening for congenital CMV and toxoplasmosis infection in severely small-for-gestational-age fetuses. B Consider obtaining testing for syphilis and malaria in high risk populations. C As per SOGC 2013 guidelines, consider obtaining maternal screening for infectious etiology in patients presenting with IUGR. B Screening for aneuploidy: As per FIGO 2021 guidelines, obtain amniocentesis for karyotype (as well as microarray and PCR for infectious agents when available) in patients with suspected fetal growth restriction, especially in cases with early-onset severe (estimated fetal weight < 3rd percentile) fetal growth restriction, in the presence of ultrasound findings associated with genetic or infectious etiologies, no obvious signs of placental dysfunction, and when the findings are likely to affect management. B As per RCOG 2013 guidelines, view a low level (< 0.415 multiples of the median) of the first- trimester marker PAPP-A as a major risk factor for delivery of a small-for-gestational-age infant. B Show 2 more As per SOGC 2013 guidelines, consider obtaining invasive testing to rule out aneuploidy in pregnancies with IUGR with suspected fetal abnormalities, soft markers, or no supportive evidence of underlying placental insufficiency. B 3. Diagnostic procedures Placental histopathology: perform histopathological examination of the placenta where available to provide useful information for counseling regarding future pregnancies. B 4. Medical management Setting of care: https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 4/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway As per FIGO 2021 guidelines, deliver fetuses with fetal growth restriction ideally at centers with the appropriate level of neonatal care for the gestational age and with the ability to perform an urgent C-section if needed. A As per ISUOG 2020 guidelines, monitor and manage pregnancies with early fetal growth restriction in tertiary-level units with the highest level neonatal care. Ensure multidisciplinary management including neonatology and maternal-fetal medicine specialists. E Specific treatment: insufficient evidence to recommend proven treatments for fetal growth restriction. I Antenatal corticosteroids: As per FIGO 2021 guidelines, use the same protocol for the administration of antenatal corticosteroids in fetal growth restriction pregnancies as used in pregnancies not affected by fetal growth restriction. Consider obtaining close fetal monitoring when antenatal corticosteroids are administered for fetuses with severe fetal growth restriction with late Doppler changes. B As per ISUOG 2020 guidelines, administer corticosteroid prophylaxis in pregnancies with early fetal growth restriction, if delivery is planned before 34+0 weeks of gestation. B As per RCOG 2013 guidelines, administer a single course of antenatal corticosteroids in females with a small-for-gestational-age fetus between 24+0 and 35+6 weeks of gestation if delivery is being considered. B As per SOGC 2013 guidelines, administer maternal corticosteroids if there is a significant possibility of delivery at < 34 weeks of gestation, as it may positively affect umbilical Doppler studies. A Magnesium sulfate: as per FIGO 2021 guidelines, use the same protocol for the administration of magnesium sulfate for neuroprotection in preterm fetal growth restriction pregnancies as used in pregnancies not affected by fetal growth restriction. B 5. Nonpharmacologic interventions Smoking cessation: As per FIGO 2021 guidelines: Advise females that smoking cessation and elimination of alcohol and illicit drugs can decrease the risk of fetal growth restriction. B Advise smoking cessation as a preventive intervention in females with a history of placenta- mediated fetal growth restriction and females at risk of preeclampsia. B As per RCOG 2013 guidelines, offer interventions to promote smoking cessation to prevent delivery of a small-for-gestational-age infant in all pregnant patients who are smoking. A As per SOGC 2013 guidelines, counsel on smoking cessation at any time during pregnancy. B 6. Therapeutic procedures https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 5/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway Indications for delivery: As per FIGO 2021 guidelines, initiate delivery irrespective of gestational age in case of biophysical profile or cardiotocography/nonstress test abnormalities (reduced variability and/or repetitive late decelerations), or severe preeclampsia with uncontrolled hypertension, HELLP syndrome, or other types of end-organ damage. A Show 8 more As per ISUOG 2020 guidelines, initiate delivery based on biophysical assessments or maternal indications in pregnancies with early fetal growth restriction, as follows: Situation Guidance Presence of maternal indication, such as severe preeclampsia, HELLP syndrome, or obstetric emergency requiring delivery E At any gestational age Personalized management E 24+0 to 25+6 weeks Spontaneous repeated persistent unprovoked fetal HR decelerations A or altered biophysical profile, score 4 E 26+0 weeks Ductus venosus a-wave is at or below baseline or short-term variation < 2.6 ms A 26+0 to 28+6 weeks Ductus venosus a-wave is at or below baseline or short-term variation < 3.0 ms A 29+0 to 31+6 weeks Umbilical artery end-diastolic flow is reversed or short-term variation < 3.5 ms E 32+0 to 33+6 weeks, permitted after 30+0 weeks Umbilical artery end-diastolic flow is absent or short-term variation < 4.5 ms. E 34+0 weeks, permitted after 32+0 weeks Show 4 more As per RCOG 2013 guidelines, initiate delivery in preterm small-for-gestational-age fetuses with umbilical artery absent or reversed end-diastolic velocities detected before 32 weeks of gestation when ductus venosus Doppler becomes abnormal or umbilical vein pulsations appear, provided the fetus is considered viable and after completion of corticosteroids. Initiate delivery by 32 weeks of gestation or consider initiating between 30-32 weeks of gestation even if venous Doppler is normal. B Show 5 more As per SOGC 2013 guidelines, decide on performing obstetrical intervention including C-section in fetus with IUGR with abnormal fetal HR or malpresentation based on fetal viability, as assessed by ultrasound. B Show 3 more https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 6/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway 7. Patient education General counseling: As per FIGO 2021 guidelines, advise females on the association of insufficient gestational weight gain with fetal growth restriction, and inform them regarding their target weight gain range. B As per SOGC 2013 guidelines: Consider offering maternal-fetal medicine consultation if the placenta appears abnormal on ultrasound, especially in the context of a growth-restricted fetus and abnormal uterine artery Doppler. B Decide between immediate delivery and transfer to a tertiary center for patients in rural settings. Consider obtaining a telephone consultation and telemedicine. B 8. Preventative measures Antiplatelet therapy: As per FIGO 2021 guidelines: Insufficient evidence to recommend routine treatment with aspirin in all females at high risk of fetal growth restriction. I Initiate aspirin (100-150 mg taken in the evening) starting at 12-16 weeks as a preventive intervention in females with a history of placenta-mediated fetal growth restriction or at risk of preeclampsia. B As per RCOG 2013 guidelines, consider initiating antiplatelet agents at or before 16 weeks of gestation B to prevent small-for-gestational-age birth in patients at high risk of preeclampsia. C As per SOGC 2013 guidelines: Initiate low-dose aspirin between 12 and 16 weeks of gestation and continue until 36 weeks in patients with a previous history of placental insufficiency syndromes including IUGR and preeclampsia. A Initiate low-dose aspirin between 12 and 16 weeks of gestation and continue until 36 weeks in patients with 2 current risk factors in pregnancy including but not limited to: maternal age > 40 years obesity multiple gestation pre-gestational hypertension pre-gestational diabetes mellitus (type 1 or 2) history of artificial reproductive technology use history of placental abruption history of placental infarction. A https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 7/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway Anticoagulant therapy: Do not use LMWH for the prevention of fetal growth restriction in females with a history of placenta-mediated fetal growth restriction or at high risk of fetal growth restriction. Limit its use to research settings. D Consider initiating LMWH in selected patients with antiphospholipid syndrome and a history of placenta-mediated fetal growth restriction, such as patients experiencing recurrent complications despite aspirin treatment (aspirin failure). C Nutrition: As per ICG 2023 guidelines, improve nutrition in pregnant individuals to prevent a substantial portion of small-for-gestational-age births. A As per RCOG 2013 guidelines, do not offer dietary modifications in order to prevent the birth of a small-for-gestational-age infant. D Other measures: As per ICG 2023 guidelines, improve hygiene and antenatal care and monitor for subclinical hypothyroidism in pregnant individuals, as well as prevent and treat malaria in endemic countries to prevent a substantial portion of small-for-gestational-age births. A As per RCOG 2013 guidelines, do not offer progesterone or calcium to prevent the birth of a small-for-gestational-age infant. D 9. Follow-up and surveillance Serial clinical assessment: As per FIGO 2021 guidelines, consider using fetal movement counting to decrease the risk of stillbirth in pregnancies with fetal growth restriction in both high- and low-resource settings. B As per RCOG 2013 guidelines: Obtain serial measurement of symphysis fundal height at each antenatal appointment from 24 weeks of gestation to improve prediction of a small-for-gestational-age infant. B Consider using a customized fetal weight reference to improve prediction of a small-for- gestational-age infant and adverse perinatal outcomes, and to improve the prediction of normal perinatal outcomes in patients undergoing serial assessment of fetal size. C As per SOGC 2013 guidelines, obtain maternal surveillance for the development of preeclampsia. B Obtain maternal surveillance for the development of preeclampsia with adverse features in patients diagnosed with IUGR due to uteroplacental vascular insufficiency. B Serial ultrasound assessment: As per FIGO 2021 guidelines: Follow a uniform protocol based on a combination of biophysical (cardiotocography/nonstress test, computerized fetal HR monitoring, biophysical profile) and cardiovascular (umbilical artery and middle cerebral artery, with or without ductus venosus Doppler) parameters along https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 8/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway with predetermined thresholds for delivery for surveillance in pregnancies with fetal growth restriction. B Consider obtaining middle cerebral artery Doppler ultrasound and measuring the cerebroplacental ratio as part of the Doppler assessment to provide additional information on fetal deterioration in pregnancies with late-onset fetal growth restriction. B As per ISUOG 2020 guidelines, schedule monitoring based on the severity of fetal growth restriction and alterations in umbilical artery Doppler. E As per RCOG 2013 guidelines, obtain serial ultrasound assessment of fetal size in patients with inaccurate measurement of symphysis fundal height (such as BMI > 35, large fibroids, hydramnios). B Show 10 more As per SOGC 2013 guidelines: Obtain surveillance in patients diagnosed with IUGR. Obtain serial ultrasound estimation of fetal weight (every 2 weeks) along with umbilical artery Doppler. Consider obtaining placental assessment and other Doppler studies, such as middle cerebral artery, umbilical vein and ductus venosis, if available. Consider offering increased frequency of surveillance. B Obtain more intensive surveillance (such as 2-3 times/week) or admit to hospital and plan delivery if fetal growth starts to plateau, amniotic fluid index starts to decline or fetal tone or gross movements are diminished or absent. B Postnatal maternal surveillance: counsel patients with a history of placenta-mediated pregnancy complications including fetal growth restriction regarding on preventive strategies as they are at an increased risk of future cardiovascular morbidity. B Show 3 more Postnatal infant surveillance, general principles: As per ICG 2023 guidelines, follow infants born small-for-gestational-age carefully in the first years of life by a neonatologist or a pediatrician to evaluate growth, weight gain, and neurodevelopment. A Show 2 more As per FIGO 2021 guidelines, follow growth-restricted infants postnatally more closely than normally grown infants as they are at an increased risk of short- and long-term morbidity. B Postnatal infant surveillance (evaluation of short stature): use national growth charts or the most appropriate growth chart for the country for accurate determination of short stature. A Show 2 more Postnatal infant surveillance (evaluation of bone maturation and mineral density): Do not obtain annual bone age assessment during GH treatment in prepubertal children as bone maturation is a poor predictor of pubertal timing and height attainment in children born small-for-gestational-age. D Consider assessing bone age around the age of 8 years and regularly from the onset of puberty onwards because an advanced bone age could be a warning sign for the presence of an underlying genetic variation, such as an ACAN mutation. Assess bone mineral density only when clinically indicated. A https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 9/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway Postnatal infant surveillance (evaluation of neurocognitive impairment): obtain early screening for neurocognitive impairment in children born preterm, children with a complicated perinatal period or a small head circumference, and pay special attention in case of developmental delay, impaired cognition, attention deficit hyperactivity disorder, or learning difficulties. A Postnatal infant surveillance (genetic testing): Consider referring children with dysmorphic features, major malformations, microcephaly, developmental delay, intellectual disability, and/or signs of skeletal dysplasia to a clinical geneticist for evaluation. B Consider obtaining genetic testing in children born small-for-gestational-age with persistent short stature with or without skeletal disproportion in the absence of other known causes. B Postnatal infant surveillance (nutrition): obtain close monitoring of weight and length trajectories to identify malnutrition, growth faltering, and excessive weight catch-up. A Show 3 more Postnatal infant surveillance (growth hormone therapy): initiate GH treatment in children born small-for-gestational-age with persistent short stature at an age after which catch-up growth is unlikely to occur (at the age of 3-4 years in most children), provided other common causes for short stature have been excluded. A Show 6 more Postnatal infant surveillance (laboratory monitoring): obtain assessment of fasting glucose and lipid concentrations only in children born small-for-gestational-age with 1 risk factors, such as overweight (BMI 1 SDS), obesity (BMI 2 SDS), ethnicity, and family history, or when clinical signs suggest a metabolic disease. B Show 3 more References 1. Henry Galan, MD, and William Grobman et al. Fetal Growth Restriction: ACOG Practice Bulletin, Number 227. Obstet Gynecol. 2021 Feb 1;137 2):e16-e28. Open 2. Anita C S Hokken-Koelega, Manouk van der Steen, Margaret C S Boguszewski et al. International Consensus Guideline on Small for Gestational Age SGA Etiology and Management from Infancy to Early Adulthood. Endocr Rev. 2023 Jan 13;bnad002. Open 3. Andrea Lausman, John Kingdom, MATERNAL FETAL MEDICINE COMMITTEE. Intrauterine growth restriction: screening, diagnosis, and management. J Obstet Gynaecol Can. 2013 Aug;35 8 741 748. Open 4. C. C. Lees, T. Stampalija, A. A. Baschat et al. ISUOG Practice Guidelines: diagnosis and management of small-for-gestational-age fetus and fetal growth restriction. Ultrasound Obstet Gynecol. 2020 Aug;56 2 298 312. Open 5. Nir Melamed, Ahmet Baschat, Yoav Yinon et al. FIGO International Federation of Gynecology and Obstetrics) initiative on fetal growth: best practice advice for screening, diagnosis, and management of https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 10/11 6/24/23, 2:34 PM Intrauterine growth restriction Pathway fetal growth restriction. Int J Gynaecol Obstet. 2021 Mar;152 Suppl 1 Suppl 1 3 57. Open 6. Royal College of Obstetricians & Gynaecologists. The Investigation and Management of the Small for Gestational Age Fetus. RCOG. 2013 Feb. Open 7. Society for Maternal-Fetal Medicine. Choosing Wisely SMFM recommendations. Choosing Wisely. 2014. Open https://web.pathway.md/diseases/rec3wccQeqIxBF2C5 11/11