Podcast Summary: Dr. Chapa’s OBGYN Clinical Pearls

Episode: GDM vs “Early” GDM vs PrePreg DM: A Proposal
Date: February 13, 2026
Host: Dr. Chapa

Episode Overview

This episode dives into the ongoing debate around the optimal timing and methodology for screening diabetes in pregnancy—distinguishing between gestational diabetes mellitus (GDM), "early" GDM, and pre-existent (pre-pregnancy) diabetes. Dr. Chapa discusses the recent trend toward screening for diabetes earlier in pregnancy, including a review of ACOG’s current recommendations and a new clinical proposal advocating for universal early screening. The episode is clinically relevant for medical students, residents, and practicing providers, blending evidence-based updates with Dr. Chapa's signature energetic, accessible style.

Key Discussion Points & Insights

1. The Diabetes Dilemma: Universal vs. Risk-based Early Screening

• Current Trends & Rationale

  • Rising BMI and weights in the U.S. population have prompted calls for earlier and/or more universal diabetes screening in pregnancy (00:38).
  • Early detection, particularly before 16–20 weeks, is unlikely to reflect metabolic changes driven by the pregnancy itself, but rather unmask pre-existing diabetes (02:00).

• ACOG’s Current Stance (July 2024 Update)

  • ACOG recommends risk-based screening for preexisting diabetes before 20 weeks. Risk factors include prior GDM, prior macrosomia, BMI >30, PCOS, first-degree relative with diabetes, and maternal age >40. (02:50, 16:09)
  • There is no mandate for universal early screening—this remains controversial due to equivocal evidence regarding improved maternal/neonatal outcomes.

• Universal Early Screening Proposal

  • Recent authors (Rochester, Montefiore, Jefferson) have proposed universal screening for all pregnancies at or before 16 weeks, with a branched algorithm based on the presence of risk factors (05:00, 18:40).
    • “They very nicely use the evidence at hand to make a very nice algorithm … and the pitch for why we really should do universal screen on every prenatal…” (05:17)
  • Dr. Chapa personally supports the universal approach, citing low risk, potential (albeit limited) benefits, and the opportunity for early education/intervention (06:00).

2. Evidence Review: Does Early Detection Improve Outcomes?

• Mixed or Modest Impact
  • Aggregate data show little evidence that early intervention for hyperglycemia substantially improves major maternal or neonatal outcomes, though there may be trends for decreased rates of macrosomia or neonatal respiratory distress (06:40, 08:39).
    • “As of right now as a whole … it doesn’t really seem to really move the needle for big bad things either on the mom or the baby side, although there is some benefit in terms of trends.” (06:45)
  • Notably, one major multicenter RCT (NEJM, 2023) demonstrated earlier GDM management led to some reduction in neonatal respiratory distress (OR 0.5, CI 0.3–0.7)—but benefits were modest and not dramatic (54:30).
    • “It wasn’t a major, it didn’t, wasn’t like a predictor prevention of stillbirth ... The benefit there, guys, was in respiratory distress … maybe needed a little CPAP, you know, oxygen, more than four hours. So it's a loose benefit.” (55:10)

3. ACOG 2024 Update: Key Reminders

• 1. Two-Step GDM Screening Preferred
  • 50g one-hour test → 100g three-hour test (Carpenter and Coustan lower thresholds now preferred) (14:30)
    • “…ACOG now recommends the lower threshold. Carpenter Costin versus National Diabetic Data Group.” (16:15)
• 2. Immediate Postpartum Glucose Screen an Option
  • Immediate 75g OGTT after 24 hours postpartum is reasonable alternative; positive results must be confirmed later (17:32).
• 3. Early Screening Methods
  • ACOG does not specify an optimal test; hemoglobin A1C, fasting blood sugar, and OGTT are all options (19:00).
    • “We don’t really know the best way to do that. Some use a hemoglobin A1C, some use a fasting plasma glucose ... we don’t really know what the best one is.” (08:26)

4. Proposed Universal Screening Algorithm (Authors’ Proposal)

• Timing: Screen at ≤16 weeks gestation (21:07)

• Algorithm Breakdown:

  A. Patients without Risk Factors
  - Perform Hemoglobin A1C - <5.7%: Normal —> Routine 24–28-week screening - 5.7%–6.4%: “Borderline” (impaired glucose tolerance) —> 75g OGTT - OGTT normal: Routine 24–28-week screening - OGTT fails (one value off): Early GDM —> Diet, monitoring, meds as needed - OGTT gross failure (FBS >126 or 2Hr >200): Pre-Gestational DM —> Full DM pathway (21:50–25:20) - “If the hemoglobin A1C is above 6.5, clearly they are already diabetic patients.” (26:04) - ≥6.5%: Diagnose as Diabetes —> Treat as preexisting DM

  B. Patients with Risk Factors
  - Go straight to 75g OGTT - If pass: Routine care, re-screen at 24–28 weeks - If FBS >126 or 2Hr >200: Diagnose as pre-existing DM, treat accordingly - If other single value abnormal: Early GDM protocol (diet, checks, meds as required) (27:41–28:40) - Risk factors include obesity, maternal age >40, prior GDM, macrosomia, family history, certain ancestry (Native American, Hispanic), PCOS, etc.

• Management Goals

  • Fasting glucose <95, 2-hr postprandial <120.

• Algorithm Summary

  • “Universal screen, either with or without risk factors. Either with the 75 gram challenge or with hemoglobin A1C.” (23:12)

5. Dr. Chapa’s Practical Takeaways

• Universal screening is efficient, potentially beneficial, and low-risk; he sees no downside as long as “we come in under 16 weeks.” (29:58)
• Above 16 weeks, might as well wait for the 24–28 week screen (participants are so close to typical screening window).
• The clinical approach may “move the needle” in the future, just as HPV screening algorithms evolved over time (56:31).
• Ultimately, both approaches—early/risk-based or universal—are currently reasonable; clinicians should be aware of their institutional protocols and patient populations.

Notable Quotes & Memorable Moments

• On universal early screening philosophy:

  “I’m a universal guy, why not? It’s a low risk test … can help with some kind of patient education and some kind of strategy for triage...”
  (03:09)

• On the lack of conclusive outcome benefit:

  “…it doesn’t really seem to really move the needle for big bad things either on the mom or the baby side, although there is some benefit in terms of trends.”
  (06:45)

• Explaining A1C cutoffs:

  “If the hemoglobin A1C is above 6.5, clearly they are already diabetic patients.”
  (26:04)

• On the real-world impact of recent RCT results:

  “It wasn’t a major, it didn’t, wasn’t like a predictor prevention of stillbirth ... The benefit there … was in respiratory distress … maybe needed a little CPAP, you know, oxygen, more than four hours. So it's a loose benefit.”
  (55:10)

• Contextual humor & personal style:

  “Are you gonna check her for the sugar? I’m like, well, what kind of sugar? Like granulated sugar, white sugar, brown sugar? What are we talking about here? Oh, you mean the diabetes. Yes, I will check her for the diabetes.”
  (01:30)

Timestamps for Key Segments

• 00:00–03:45: Diabetes: cultural commentary, rising BMIs, rationale for early screening
• 03:46–08:16: Universal vs. risk-factor-based screening; review of ACOG recommendations
• 08:17–09:56: Outcome data: Does early identification help? Minor/neonatal outcomes
• 14:24–20:00: 2024 ACOG GDM screening update: Two-step preferred, diagnostic thresholds
• 21:07–28:40: Universal screening proposal: full algorithm explained
• 54:30–56:31: Review of evidence, NEJM 2023 trial—benefit clarifications
• 56:32–End: Clinical pearls, shifting guidelines, comparison to HPV screening evolution

Conclusion

Dr. Chapa thoroughly reviews the new clinical opinion advocating for universal early diabetes screening (≤16 weeks’ gestation) with a logical, practical algorithm based on current risk factors and available evidence. While the clinical benefit in hard outcomes remains unclear, the move towards earlier or universal screening is gaining momentum, and is supported by practical workflow efficiencies, possible modest neonatal benefits, and alignment with the rising prevalence of obesity and diabetes risk in reproductive-age patients.

Bottom line for clinicians:
Both risk-based and universal early screening are defensible according to current evidence and guidelines. ACOG prefers the former, but the “needle is moving” toward the latter. Know your options—and your patient population.