Your Baby Is Growing Big
Understanding Large for Gestational Age (LGA)
What Is LGA?
Your baby's estimated weight is at or above the 90th percentile for this stage of pregnancy.
≥ 90th %ile = LGA
Definition per ACOG Practice Bulletin #230 & SMFM
How We Measure Your Baby's Size
Ultrasound
Measures head, abdomen & femur to estimate fetal weight (EFW)
Margin of Error
EFW can be off by ±10–15% — especially in late pregnancy
The weight on screen is an estimate, not a certainty. We use it as a guide, not a verdict.
What Causes a Large Baby?
Pre-pregnancy Obesity
Strongest modifiable risk factor (Adj. OR 2.73)
Diabetes in Pregnancy
Gestational or pre-gestational diabetes
Excessive Weight Gain
Gaining more than recommended during pregnancy
Prior Large Baby
History of delivering a large infant (multiparity)
ACOG Practice Bulletin #230 · SMFM Consult Series
Blood Sugar Drives Growth
Controlling blood sugar is the single most effective way to slow excessive fetal growth.
Potential Risks — For You & Baby
Our team monitors for each of these. Most LGA pregnancies deliver safely.
What Is Shoulder Dystocia?
What happens
After the head delivers, the baby's shoulder becomes briefly impacted against the pelvis (pubic symphysis).
Our response
Our team trains regularly in proven maneuvers to safely deliver your baby. You are in expert hands.
“Should We Deliver Early?”
Early Induction
- Does not reduce cesarean rate
- Does not reduce shoulder dystocia
- May increase risk of failed induction
Monitor & Plan
- Continued growth surveillance
- Optimize glucose control
- Individualized birth planning
Suspected macrosomia alone is NOT an indication for induction before 39 weeks 0 days. Earlier delivery increases neonatal morbidity without improving outcomes.
When We Recommend a Cesarean
| Clinical Situation | EFW Threshold |
|---|---|
| No diabetes | > 5,000 g |
| Diabetes present | > 4,500 g |
| Prior shoulder dystocia | Discuss with your provider |
These are guideline-based thresholds — not automatic decisions. We discuss your individual situation together.
ACOG Practice Bulletin #230 on Fetal Macrosomia
Your Role in Your Baby’s Health
- ✓ Attend all scheduled growth scan appointments
- ✓ Monitor and log blood sugars as recommended
- ✓ Follow your nutrition plan — consistent meals, limit refined carbohydrates
- ✓ Report any decreased fetal movement promptly
- ✓ Know your signs of labor and when to go to the hospital
After Your Baby Arrives
These are routine precautions — not emergencies. Our team is prepared and watching.
Your Child’s Long-Term Health
Higher Risk Without Action
Insulin resistance, obesity, and early cardiovascular disease in children born LGA
Healthy Habits Change the Story
Active lifestyle, balanced nutrition, and regular pediatric check-ups make a real difference
What Happens Next
You Are Not Alone in This
Our team is with you every step of the way.
Ask questions. Share concerns. We plan together.
MFM Care Team · ACOG Practice Bulletin #230 · SMFM Guideline-Based Counseling