Podcast Summary: Dr. Chapa’s OBGYN Clinical Pearls

Episode: QUICKIE: AC v EFW for FGR Care

Release Date: March 7, 2026
Host: Dr. Chapa

Main Theme

This concise “Quickie” episode offers a rapid, practical review of how to diagnose and manage fetal growth restriction (FGR) based on abdominal circumference (AC) versus estimated fetal weight (EFW) in clinical obstetrics. Dr. Chapa addresses a common clinical confusion: when a fetus is diagnosed with FGR by AC but has a normal EFW, how should management—including timing of delivery—be determined? The episode draws from ACOG Practice Bulletin 227 and Committee Opinion 831.

Key Discussion Points & Clinical Insights

The "Quickie" Format (00:00–01:59)

• This episode debuts the "Quickie" format: short, focused updates interspersed between longer regular episodes.
• Intended to rapidly highlight recent experience or clarify a common clinical pearl.

Defining Fetal Growth Restriction (FGR) (02:01–03:12)

• Diagnostic criteria:
  • Abdominal circumference (AC) <10th percentile for gestational age, or
  • Estimated fetal weight (EFW) <10th percentile for gestational age.

  “It’s not one and the other—it’s ‘or’.” (Dr. Chapa, 02:28)

• Cites SMFM, ACOG Practice Bulletin 227, and Committee Opinion 831 as sources.

Clinical Pearl: The Discrepancy Case (03:15–04:56)

• Case example:
  • Patient at 38 weeks: AC at 6% (meets FGR diagnosis), EFW at 16% (normal).
• Teaching point:
  • Either AC or EFW under the 10th percentile can earn the diagnosis.
  • AC often the first parameter to lag due to loss of fat/glycogen stores—analogous to ferritin dropping before H&H in iron deficiency.

“Abdominal circumference will be the first thing that lags as the baby's fat stores are depleted...then the total EFW will show up as lagging.” (Dr. Chapa, 04:16)

Management Versus Diagnosis—Where Does Each Fit? (06:44–09:42)

• Surveillance is triggered by AC <10%:

  • Flag chart as FGR.
  • Over 32 weeks: Add umbilical artery Dopplers for surveillance.

• Delivery timing is NOT based on AC alone—it's based on EFW and Dopplers:

  • If EFW >10%, may manage as routine and can plan for induction at 39 weeks.

    “Even though the child has a diagnosis of FGR…you could actually go until 38 or 39 weeks as a delivery plan because the percentage of the fetal weight was normal.” (Dr. Chapa, 07:01)

  • If EFW 3rd–10th percentile, induction between 38+0 and 39+0 weeks is recommended.
  • If EFW <3rd percentile (severe FGR) or abnormal Dopplers, deliver at 37 weeks or upon diagnosis.
  • Doppler findings guide early delivery:
    • Elevated SD or resistance index (>95th percentile): deliver at 37 weeks.
    • Absent end-diastolic flow: deliver at 33–34 weeks.
    • Reversed flow: deliver at 30–32 weeks (poor prognosis).

“While the diagnosis can be made by abdominal circumference, the delivery planning is based on EFW percentages and or on the Doppler studies.” (Dr. Chapa, 07:30)

“If the EFW is normal, meaning above the 10th percentile, just do a regular induction at 39 weeks.” (Dr. Chapa, 08:10)

Memorably Clear Recap (09:45–10:54)

• Diagnosis: Either AC or EFW <10th percentile.
• Management: Based on EFW (and Doppler), not AC.
  • Serial growth ultrasounds, umbilical artery Dopplers for AC <10%.
  • Delivery timing references EFW/Doppler, not AC.

“The final decision for delivery is not based on abdominal circumference. It's based on EFW and umbilical artery Dopplers.” (Dr. Chapa, 10:45)

Notable Quotes & Memorable Moments

• Dr. Chapa sets the tone for “Quickie” segments:

  “Welcome to the first of what is meant to be recurrent periodic episodes called the Quickie...just to relay some quick information out, maybe something we see in practice or something that comes out in print as a quick reminder or as a quick heads up about something in clinical practice as it affects women’s health and OB GYN.” (00:00)

• On clinical confusion:

  “This did cause confusion in our clinic because—wait, she's growth restricted...that diagnosis does not go away. But delivery management is only based on EFW percentile and/or the umbilical artery Doppler studies.” (Dr. Chapa, 09:42)

• On reinforcing the take-home message:

  “Abdominal circumference gets the flag if you find that antepartum...But the final decision for delivery is not based on abdominal circumference. It’s based on EFW and umbilical artery dopplers.” (Dr. Chapa, 10:45)

Timestamps for Important Segments

| Segment | Timestamp | |-----------------------------------------------|----------------| | Intro to the “Quickie” format | 00:00–01:59 | | FGR Diagnostic Criteria (AC vs EFW) | 02:01–03:12 | | Clinical logic behind AC/EFW discrepancy | 03:15–04:56 | | Management (Surveillance, Delivery Timing) | 06:44–09:42 | | Clear Recap/Conclusion of Key Pearl | 09:45–10:54 |

Conclusion

This episode swiftly clarifies a high-yield clinical misunderstanding: while AC <10% or EFW <10% constitutes FGR diagnosis, the timing of delivery should be guided by EFW and umbilical artery Doppler studies—not the AC result alone. Clinicians are reminded to flag patients for surveillance based on AC but to plan deliveries based on EFW/Doppler, referencing ACOG’s latest guidance for optimal care.

“Abdominal circumference diagnosis—EFW or Doppler for management!” (Implied summary—Dr. Chapa’s core clinical pearl)

For more clinical pearls and clarifications, stay tuned to Dr. Chapa’s OBGYN Clinical Pearls podcast!