Podcast Summary: Dr. Chapa’s Clinical Pearls

Episode: Excessive Maternal Weight Gain (GWG) = Stillbirth?
Date: February 17, 2025
Host: Dr. Sam (Dr. Chapa)

Episode Overview

This episode takes a deep dive into one key clinical question: Does excessive gestational weight gain (GWG) increase the risk of stillbirth? Dr. Sam dissects large-scale studies from 2001 to 2019, explains established clinical guidelines, and addresses a nuanced listener question regarding weight gain and fetal surveillance. While excessive GWG is known to increase the risk of various maternal and perinatal complications, its direct link to stillbirth is more complex—and not what most clinicians and learners might expect.

Key Discussion Points & Insights

Setting the Stage: Obesity, GWG, and Guidelines

• Rising BMIs in the U.S.:
  • 1 in 5 women enter pregnancy with a BMI ≥30 (00:50).
  • 1 in 5 women gain >40 lbs during pregnancy—exceeding guidelines (01:10).
  • Only 1/3 of women gain the recommended amount during pregnancy.
• GWG vs. Pre-pregnancy BMI:
  • Pre-pregnancy BMI is an established independent risk factor for complications including stillbirth.
  • Clinical Guidance:
    • Antepartum fetal surveillance is initiated based on pre-pregnancy BMI per ACOG Committee Opinion 828:
      • BMI 35–39.9: surveillance at 37 weeks
      • BMI ≥40: surveillance at 34 weeks (03:20)
• Common Knowledge: Excessive GWG increases risk of preeclampsia, gestational diabetes, macrosomia, shoulder dystocia, and preterm birth.

Central Clinical Question

“Is gestational weight gain (GWG) an indication for antepartum fetal surveillance, and is it linked to stillbirth?”
—Listener question, as paraphrased by Dr. Sam (04:30)

Walking Through the Evidence Timeline

1. 2001 AJOG (American Journal of OB GYN): Swedish Population-Based Case-Control Study

• Key Finding:

  “Maternal overweight condition increased the risk of antepartum stillbirth…whereas weight gain during pregnancy was not associated with any risk.” (10:50)

• Interpretation:
  • Pre-pregnancy overweight = higher risk
  • Gestational weight gain = not linked to stillbirth

2. 2012: Journal ‘Obesity’—Rotterdam Cohort

• Key Finding:

  “As compared to entering pregnancy overweight or obese, excessive gestational weight gain has a limited influence on adverse pregnancy outcomes.” (13:15)

• Interpretation:
  • Main driver of risk: initial BMI, not excessive gain during pregnancy

3. 2013 & 2023: ACOG Guidance on GWG

• Recommendations for weight gain based on BMI remain unchanged since 2013, reaffirmed in 2023 (15:10).

4. 2017: BJOG—Swedish Population-Based Cohort

• Key Finding:

  “We found no association between total or early pregnancy weight gain and stillbirth across the range of weight gain experienced by most women.” (16:30)
  “There was no association between maternal weight gain during pregnancy and stillbirth among most women.” (tweetable abstract)

• Interpretation:
  • For the vast majority, excess GWG not linked to stillbirth

5. 2017: Annals of Epidemiology—US Cohort

• Key Finding:

  “Stillbirth risk increased with inadequate weight gain and weight loss in all BMI classes except the morbidly obese group, where weight demonstrated a protective effect. Conversely, excessive weight gain was associated with higher risk of stillbirth among the obese and the morbidly obese women, but excessive weight gain was protective against stillbirth in those with lower weight at initiation.” (24:30)

• Nuance:
  • Low GWG / weight loss: Higher risk of stillbirth (except morbidly obese)
  • Excessive GWG:
    • Obese/morbidly obese: Possibly increased risk, though confounded by already high baseline risk
    • Underweight at baseline: Protective against stillbirth

6. 2019: BMC Pregnancy & Childbirth—Case-Control Using GWG Z Scores

• Key Finding:

  “In adjusted analyses…the odds of stillbirth were elevated for women with very low gestational weight gain…A gestational weight gain level that is harmful for the mother may not always be harmful for the fetus.” (28:40)

• Interpretation:
  • Too little weight gain: Increased stillbirth risk
  • Excessive GWG: Not generally associated with increased stillbirth risk (except possible nuance in higher classes of obesity)
  • Excess GWG adverse primarily for maternal health, not directly for fetal stillbirth risk

Practical Clinical Implications

• No indication for antepartum surveillance based solely on excessive GWG (30:00)
• Surveillance remains dictated by pre-pregnancy BMI or other medical comorbidities
• Key Guidance for Providers:
  • Excessive GWG should still be managed due to risks of hypertension, GDM, macrosomia, and maternal metabolic health
  • Low weight gain/confined to underweight patients: Key situation where stillbirth risk rises and requires attention

Notable Quotes & Memorable Moments

• “Does maternal weight gain actually affect this thing? Well, I'm going to tell you, based on a bulk of data for like 18 years, why gestational weight gain is not listed on that table for antepartum surveillance.” (10:20)
• “A gestational weight gain level that is harmful for the mother may not always be harmful for the fetus.” (28:50)
• “Excessive weight gain is somewhat dependent on where the woman started in her BMI class. Underweight could actually be helpful as a protective effect against stillbirth.” (25:15)
• “Does excessive maternal weight gain or GWG increase stillbirth? The answer is likely no. That's why we don't do antepartum fetal surveillance in that case.” (31:50)
• Humorous aside: “I ate a cupcake out of the trash can last night… that's pregnancy hormone driven and I don't recommend eating cupcakes out of the trash, just FYI.” (09:44)

Important Timestamps

• 00:50: U.S. BMI stats & introduction to the GWG vs BMI question
• 03:20: ACOG’s fetal surveillance recommendations by BMI
• 08:16 – 09:44: (Skip) Ads and movie anecdote
• 10:50: 2001 AJOG—first population data point
• 13:15: 2012 Obesity journal—limited influence of excess GWG
• 15:10: ACOG GWG guideline history
• 16:30: 2017 BJOG—no link GWG & stillbirth
• 24:30: 2017 Annals of Epidemiology—US data, nuanced GWG findings
• 28:40: 2019 BMC study—Z scores and stillbirth, harm distinction
• 30:00: Clinical pearls recap: GWG & antepartum surveillance
• 31:50: Take-home message & closing

Final Takeaway

Excessive gestational weight gain, by itself, is NOT an independent risk factor for stillbirth and does not warrant antepartum fetal surveillance.

• Pre-pregnancy BMI remains the relevant risk for surveillance.
• Low or inadequate GWG, especially among underweight women, is associated with increased stillbirth risk.
• Excess GWG should still be avoided for many other medical and perinatal reasons.

Dr. Sam keeps clinical education engaging and evidence-based, ending with thanks to listeners and a reminder: Don’t ignore GWG, but know where the real risk for stillbirth lies.

For a thorough, evidence-based exploration, this episode offers clarity on a standing clinical myth and delivers practical guidance to learners and practitioners alike.