Learning Objectives and CME/Disclosure Information

This activity is intended for healthcare providers delivering care to women and their families.

After completing this activity, the participant should be better able to:

1. Discuss the definitions associated with fetal growth restriction (FGR)
2. Describe the fetal assessment options when a patient has been diagnosed with FGR

Estimated time to complete activity: 0.25 hours

Faculty:

Susan J. Gross, MD, FRCSC, FACOG, FACMG President and CEO, The ObG Project

Disclosure of Conflicts of Interest

Postgraduate Institute for Medicine (PIM) requires faculty, planners, and others in control of educational content to disclose all their financial relationships with ineligible companies. All identified conflicts of interest (COI) are thoroughly vetted and mitigated according to PIM policy. PIM is committed to providing its learners with high quality accredited continuing education activities and related materials that promote improvements or quality in healthcare and not a specific proprietary business interest of an ineligible company.

The PIM planners and others have nothing to disclose. The OBG Project planners and others have nothing to disclose.

Faculty: Susan J. Gross, MD, receives consulting fees from Cradle Genomics, and has financial interest in The ObG Project, Inc.

Planners and Managers: The PIM planners and managers, Trace Hutchison, PharmD, Samantha Mattiucci, PharmD, CHCP, Judi Smelker-Mitchek, MBA, MSN, RN, and Jan Schultz, MSN, RN, CHCP have nothing to disclose.

Method of Participation and Request for Credit

Fees for participating and receiving CME credit for this activity are as posted on The ObG Project website. During the period from 12/01/2022 through 12/01/2024, participants must read the learning objectives and faculty disclosures and study the educational activity.

If you wish to receive acknowledgment for completing this activity, please complete the test and evaluation. Upon registering and successfully completing the test with a score of 100% and the activity evaluation, your certificate will be made available immediately.

Joint Accreditation Statement

In support of improving patient care, this activity has been planned and implemented by the Postgraduate Institute for Medicine and The ObG Project. Postgraduate Institute for Medicine is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.

Physician Continuing Medical Education

Postgraduate Institute for Medicine designates this enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Continuing Nursing Education

The maximum number of hours awarded for this Continuing Nursing Education activity is 0.2 contact hours.

Read Disclaimer & Fine Print

SUMMARY:

SMFM has released guidance on fetal growth restriction (FGR), an evidence-based document that provides a standardized approach to diagnosis and management. The document emphasizes the importance of FGR as a significant pregnancy complication that

…occurs in up to 10% of pregnancies and is second to premature birth as a cause of infant morbidity and mortality. In addition to its significant perinatal impact, FGR also has an impact on long-term health outcomes

• Diagnosis of FGR and Definitions
• FGR Workup
• Fetal Assessment
• FGR Prevention and Treatment
• FGR Delivery Timing

Diagnosis of FGR and Definitions

ACOG FGR Definition

• FGR: EFW <10th percentile for gestational age
• Small for gestational age (SGA): Newborn birthweight <10th percentile for gestational age

SMFM FGR Definition

• SMFM supports the above ACOG definitions
• SMFM also includes AC
• Screening performance similar between EFW and AC (see ‘Related ObG Topics’ below)

Note: The term ‘IUGR’ should no longer be used | SMFM document, based on more recent evidence, does not consider symmetric vs asymmetric FGR to be helpful in determining prognosis

Early onset FGR: <32 weeks

• More severe disease course and more likely to be associated with
  • Placental insufficiency
  • Hypertensive disorders
  • Genetic disorders
  • Maternal hypertension
  • Doppler abnormalities

Late onset of FGR ≥32 weeks

• Accounts for 70-80% cases
  • Generally, milder clinical course and without flow abnormalities

Severe FGR

• EFW <3rd percentile
• Consistent with a more severe form of FGR

KEY POINTS:

FGR Workup

• Detailed ultrasound
  • Strong association with fetal anomalies and/or chromosomal disorders (20%)
  • Detailed ultrasound CPT code: 76811
• Genetics and fetal diagnostic testing: Chromosomal Microarray Analysis (see ‘Related ObG Topics’ below) is indicated for the following
  • FGR <32 weeks
  • FGR and polyhdramnios and/or fetal malformation are detected regardless of gestational age
• Viral work-up
  • CMV testing
    • Associated with isolated FGR | However, routine testing not recommended due to low CMV incidence
    • Offer CMV (PCR) if patient undergoing amniocentesis
  • Toxoplasmosis, rubella, or herpes and isolated FGR
    • Routine screening is not recommended unless other risk factors are identified

Fetal Assessment

NST (Cardiotocography [CTG])

• Weekly NSTs after viability
• Increase frequency if warranted based on Doppler abnormalities or other clinical indications (e.g. comorbidities or risk factors)
• SMFM addresses BPP in the statement and finds that “further studies are required to prove usefulness of BPP”

Umbilical Artery (UA) Doppler Measurement

• Normal flow measurements
  • UA Dopplers every 1 to 2 weeks
• Abnormal end diastolic velocity (EDV)
  • Decreased EDV (flow ratios >95th percentile) or FGR <3rd percentile: Weekly Dopplers
  • Absent end diastolic velocity (AEDV): 2 to 3 times/week
  • Reversed end diastolic velocity (REDV)
    • Hospitalize
    • Administer antenatal corticosteroids
    • Perform NST 1 to 2 times/day | Low threshold for delivery depending on clinical scenario

Note: SMFM recommends against routine use of ductus venosus dopplers, middle cerebral artery dopplers, or uterine artery Doppler studies in early or late onset FGR | These studies have not been found to lead to improved accuracy over umbilical artery dopplers

FGR Prevention and Treatment

Prevention

• Due to lack of evidence, SMFM recommends against the use of the following for prevention of FGR
  • Prenatal aspirin (conflicting data including negative result in ASPRE trial)
  • LMWH

Treatment

• SMFM recommends against the use for treatment of FGR
  • Sildenafil
  • Activity restriction

FGR Delivery

Timing

• With oligohydramnios: 34w0d to 37w6d
• Normal UA Doppler and EFW 3 to 10th percentile: 38 to 39 weeks
• EFW <3rd percentile (severe FGR): 37 weeks
• Decreased UA flow (S/D, RI, or PI > 95 percentile): 37 weeks
• AEDV: 33 to 34 weeks
• REDV: 30 to 32 weeks

Mode of Delivery

• Cesarean delivery
  • No strict recommendation for cesarean delivery based on FGR alone
  • Reserve for usual fetal and maternal indications
• Mode of delivery for most cases of severe FGR with umbilical artery changes (AEDV or REDV): Cesarean delivery for fetal indication
• Mode of delivery should be determined on a case-by-case basis, taking in to account clinical presentation and maternal preferences

FGR and Preterm

• Administer corticosteroids and magnesium sulfate as per current guidelines

Learn More – Primary Sources:

SMFM Consult Series 52: Diagnosis and Management of Fetal Growth Restriction

ACOG Practice Bulletin 227: Fetal Growth Restriction

Related ObG Topics:

Fetal Growth Restriction: Definition, Evaluation and Management

Antenatal Corticosteroids – When to Administer?

ACOG Recommendations: When to Deliver Medically Complicated Pregnancies

Can Abdominal Circumference Alone Be Used to Predict SGA or LGA Newborns?

The Use of Microarrays in the Prenatal and Postnatal Setting – Current Professional Guidelines

ASPRE Trial: A Combined Risk Algorithm and Use of Aspirin to Prevent Preterm Preeclampsia