Dr. Chapa’s OBGYN Clinical Pearls

Episode: You Ask, We Answer!
Airdate: February 8, 2026
Host: Dr. Chapa

Episode Overview

In this lively, clinically relevant episode, Dr. Chapa answers two nuanced, evidence-based listener questions from the “podcast family,” diving into the subtleties of Rh immunoglobulin (RhIG) prophylaxis after trauma and the classification and implications of silent or partial uterine rupture. The episode is packed with practical pearls and aims to clarify real-world ambiguities in ACOG guidance, all delivered in Dr. Chapa’s energetic, student-centric style.

Key Discussion Points & Insights

[08:05] RhIG (Rhogam) Prophylaxis: Repeat Dose After Trauma?

• Clinical Scenario:
  A patient receives her routine 28-week RhIG prophylaxis, then suffers minor trauma (a fall) two weeks later. Does she need another dose?

• Immediate Takeaway:
  Yes, she does need an additional dose. Even if RhIG was given recently, any new potential fetomaternal hemorrhage event (like trauma) requires a repeat dose.

• Rationale and Evidence:

  • Routine 28–30 week prophylaxis is intended for silent micro-breaks in the fetomaternal barrier—“that’s your maintenance therapy.” [09:05]
  • “Any sensitizing event—a trauma, an external cephalic version, anything like that that could lead to a potential maternal and fetal break...needs a separate RhIG administration.” [09:45]
  • The half-life of anti-D immunoglobulin is about 23 days in the third trimester, but that doesn’t mean protection is absolute or event-specific after the first dose.
  • Analogy:
    “It’s like a patient who has diabetes and they're on Lantus...however, they still may need PRN Lispro or regular for the acute episodes. Same thing here.” [10:42]
  • Guidance from ACOG Practice Bulletin 181 is explicit:
    • Routine dose is for maintenance/microbreaks; sensitizing events require additional prophylaxis.
    • Notable Quote:
      “In any potential break, like trauma, then it is recommended to give Rhogam to cover anything else.” [11:35]

• Kleihauer-Betke (KB) Stain Clarification:

  • The KB is performed not to withhold a dose, but to determine if more than one dose is needed.
  • “Even if the KB is negative, you still give a dose of Rhogam...” [12:12]

• Dose Reference:

  • One standard dose (300 mcg) covers ~15 ml fetal RBCs (30 ml whole blood).
  • Additional doses are seldom needed unless there is significant hemorrhage.

• Guidance Contradiction (and Dr. Chapa’s Advice):

  • Contradiction:
    • ACOG: For trauma, always repeat dose.
    • Same bulletin: If delivery occurs <3 weeks after dose, postnatal RhIG may be withheld.
  • “At delivery—don’t worry about it if she got Rhogam within three weeks...you may consider withholding that. That doesn’t make any sense.” [14:56]
  • Real-world pearl:
    • “Knowing that contradiction—let me give you a real-world application... Personally, I would give her another dose.” [16:37]
    • If in doubt, give the dose. Risk of alloimmunization outweighs risks of RhIG administration.

• Memorable Wrap-Up:

  • “The 28-week RhIG is your maintenance kind of dose—that’s your Lantus...the PRN dosages are your Lispro or regular insulin for acute episodes.” [18:00]

[20:16] Silent (Partial) Uterine Rupture at Cesarean—Definition & Management

• Clinical Scenario:
  At C-section, you find the serosa and myometrium open but fetus and sac intact. Is this a uterine rupture?

• Key Definitions:

  • Uterine Window: Myometrium separated, serosa intact.
  • Partial (Silent) Rupture: Serosa and myometrium open, amniotic sac intact, fetus inside uterus.
  • Complete (Symptomatic) Rupture: Serosa/myometrium open, fetus partly or wholly outside uterus.

• Incidence & Clinical Significance:

  • Partial ruptures = ~50% of all uterine ruptures. Often incidental/asymptomatic.
    • “By definition, a partial uterine rupture is asymptomatic and silent. Crazy, huh?” [21:15]
  • Complete ruptures present with classic signs (FHR decels, bleeding, loss of station, etc.) and have higher morbidity.

• Management Pearls:

  • Repair the rupture as found.
  • Counsel patients for future planned C-section, possibly as early as 37 weeks (or 36 weeks for classical incisions or myomectomy/previous rupture).
    • “In the future she should really have a scheduled plan C-section.” [22:55]
  • Primary risk factor for complete rupture: TOLAC (trial of labor after cesarean), especially if on Pitocin.
  • Partial ruptures most often occur at prior C-section sites, but also possible in unscarred uteri (e.g., due to adenomyosis, prior D&C).

• Clinical Reassurance:

  • “Not all uterine ruptures, thankfully, are catastrophic. Some are indeed found as an incidental finding. Fascinating, fascinating, fascinating.” [24:04]

Notable Quotes & Memorable Moments

• [09:45]
  “Any sensitizing event...needs a separate RhIG administration.” —Dr. Chapa

• [10:42]
  “It’s like...diabetes on Lantus...but may need PRN Lispro. Same thing here.”

• [11:35]
  “In any potential break, like trauma, then it is recommended to give Rhogam to cover anything else.”

• [14:56]
  “At delivery—don’t worry about it if she got Rhogam within three weeks...you may consider withholding that. That doesn’t make any sense.”

• [16:37]
  “Personally, I would give her another dose...If in doubt, just give it.”

• [18:00]
  “The 28-week RhIG is your maintenance kind of dose—that’s your Lantus...the PRN dosages are Lispro for acute episodes.”

• [21:15]
  “By definition, a partial uterine rupture is asymptomatic and silent. Crazy, huh?”

• [22:55]
  “In the future she should really have a scheduled plan C-section.”

• [24:04]
  “Not all uterine ruptures, thankfully, are catastrophic. Some are indeed found as an incidental finding. Fascinating, fascinating, fascinating.”

Timestamps for Key Segments

• [08:05] | Start of RhIG repeat dose question discussion
• [09:45] | Key principles on event-specific RhIG dosing
• [12:12] | KB stain: role and limits
• [13:50–16:37] | Practice Bulletin contradiction & practical advice
• [18:00] | Summary analogy: Lantus/RhIG and Lispro/PRN dosing
• [20:16] | Introduction of silent/partial uterine rupture question
• [21:15] | Types of uterine rupture explained
• [22:55] | Counseling patients after partial rupture
• [24:04] | Clinical reassurance, concluding remarks

Summary Table

| Question | Clinical Pearl | Guideline Reference | |----------------------------------------------|-----------------------------------------------------------------------|------------------------------------| | Repeat RhIG after trauma soon after routine? | Always give a repeat dose for any sensitizing event. | ACOG PB 181 (with noted caveats) | | Partial/silent rupture found at C-section? | Yes, this is a partial uterine rupture—repair and plan future Cesarean| Standard OB surgical management |

Conclusion

This episode is a perfect example of Dr. Chapa’s mission: making complex clinical guidance digestible and useful for OB/GYN providers at all levels. He clarifies tricky contradictions, provides actionable recommendations, and brings humor and practical analogies to essential women’s health topics. If in doubt, treat sensibly and prioritize patient safety!