Patient handout

Gestational Diabetes Mellitus (A1 / A2 — OB perspective)

PRODUCTION

1. Your condition

This handout is for gestational diabetes mellitus (a1 / a2 — ob perspective). Your care team identified this based on: pregnancy at 24-28 weeks → universal gdm screening (uspstf 2021, pmid 34374716; acog 190).

Other reasons your team may use this plan: early pregnancy + high-risk profile (bmi ≥ 30, prior gdm, prior macrosomia, pcos, ethnic risk, family dm2) → early gdm screen (acog 190); 50-g gct ≥ 140 mg/dl → proceed to 100-g 3-h ogtt (carpenter-coustan or nddg) (acog 190); 75-g 2-h ogtt positive (fasting ≥ 92, 1-h ≥ 180, 2-h ≥ 153) → gdm diagnosis (iadpsg 2010, pmid 20190296).

3. Your action plan

Use these zones to know what to do based on how you feel.

GREEN — On target — SMBG within range, no symptoms, normal kick counts

If you have:

Fasting < 95 mg/dL (ACOG 190 + ADA 2025)
1-h postprandial < 140 mg/dL OR 2-h PP < 120 mg/dL (ACOG 190 + ADA 2025)
Normal fetal kick counts (≥ 10 in 2 h) (ACOG 190)
No symptoms of hypoglycemia OR hyperglycemia

Do this:

Continue MNT (35-45% carb, 3 meals + 2-3 snacks) (ACOG 190)
Continue insulin or metformin as prescribed (ACOG 190; ADA 2025 §15)
Continue 30 min/day moderate exercise (ADA 2025 §15)
Continue aspirin 81 mg daily through 36 weeks if started (USPSTF 2021)
SMBG QID + log values (ACOG 190)
Daily kick counts from 28 wk (ACOG 190)
Attend all scheduled prenatal visits + NSTs + growth scans (ACOG 190)

YELLOW — Caution — Out of range, mild symptoms, or new concern

If you have:

Fasting 95-125 OR 1-h PP 140-180 OR 2-h PP 120-160 mg/dL repeatedly (ACOG 190)
Mild hypoglycemia (BG 55-69) responding to 15 g carb rule (ACOG 190)
Reduced (but not absent) fetal movement (ACOG 190)
Mild swelling or weight gain accelerating > 1 lb/wk (ACOG 190)
Single severe-range hyperglycemic reading without symptoms

Do this:

Recheck SMBG before next meal (ACOG 190)
Review carb intake at meal causing elevation (ACOG 190)
If hypoglycemic, 15 g fast-acting carb + recheck in 15 min (ACOG 190)
Drink water + lie left-side if reduced fetal movement (ACOG 190)
Daily kick count focused 1-h count (ACOG 190)
Call OB or GDM clinic same business day (ACOG 190)
Continue insulin/metformin + MNT as prescribed (ACOG 190)

Call your provider if:

SMBG values out of range > 2 consecutive readings at same time-of-day (ACOG 190)
Persistent reduced fetal movement (ACOG 190)
Accelerating weight gain > 1 lb/wk over baseline (ACOG 190)
Mild hypoglycemia twice in same day (ACOG 190)

RED — Medical alert — go to L&D / ED now

If you have:

Severe hyperglycemia BG > 250 mg/dL with ketones in urine or symptoms (nausea, vomiting, abdominal pain) (Sibai 2014 PMID 24463678 — DKA-in-pregnancy thresholds lower)
Severe hypoglycemia BG < 55 mg/dL with neuroglycopenia (confusion, seizure, LOC)
Severe headache not relieved by acetaminophen, visual changes, RUQ pain (PE severe features per ACOG 222)
BP ≥ 160/110 on home cuff (single reading) or two readings ≥ 150/100 in 15 min (ACOG 767)
Decreased fetal movement (< 10 kicks in 2 h after focused counting) (ACOG 190)
Vaginal bleeding, leaking fluid, contractions (ACOG 190)
Seizure or loss of consciousness (ACOG 190 + ACOG 222)

Do this:

Go to L&D / ED immediately — do not wait (ACOG 190)
Call 911 if seizing or unable to travel safely (ACOG 190)
Bring insulin/metformin list, SMBG log, BP log (ACOG 190)
If hypoglycemic + conscious: take 30 g carb + go to ED (ACOG 190)
If hyperglycemic + symptoms: bring urine ketone strip result (Sibai 2014 PMID 24463678)

Call your provider if:

Any red-zone trigger — proceed to L&D, do not call first (ACOG 190)

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

GDM detected in first trimester via early screen (BMI ≥ 30, prior GDM, prior macrosomia, PCOS, ethnic risk, family DM2) → likely pre-existing T2DM unmasked; A1c ≥ 6.5% at conception → major-malformation risk 6-12% (Kitzmiller diabetes-in-pregnancy review)
A2 GDM with ≥ 50% glucose values exceeding target at multiple time-of-day points despite maximal insulin titration (basal + bolus per pattern) for 2-3 weeks → intensify insulin + endocrinology consult + MFM coordination + consider CGM (CONCEPTT 2017 PMID 28923465 evidence base in T1DM; off-label use in GDM)
GDM with estimated fetal weight (EFW) ≥ 95th percentile (macrosomia ≥ 4000 g) OR amniotic fluid index (AFI) > 24 (polyhydramnios) → tighten glucose control + delivery timing reassessment + shoulder dystocia counseling; cesarean for EFW ≥ 4500 g per ACOG 190 (vs ≥ 5000 g in non-DM)
A2 GDM patient on insulin with recurrent hypoglycemia (≥ 2 episodes of BG < 70 mg/dL per week, or ≥ 1 severe episode requiring assistance/dextrose) → adjust insulin regimen + nutritional reassessment + CGM consideration; rule out renal dysfunction, hyperemesis-with-poor-intake, exercise-induced hypoglycemia
GDM patient develops new HTN ≥ 140/90 with proteinuria OR any severe-feature symptom (severe headache, visual changes, RUQ pain, plt < 100K, AST/ALT ≥ 2× ULN, Cr ≥ 1.1, pulmonary edema) after 20 wk → reclassify as superimposed pre-eclampsia + carryover handoff to ob.pre-eclampsia.core.v1 (overlap 4-5× per HAPO-FUS)
DKA in pregnancy with GDM — anion gap > 12 + ketonemia (serum ketones positive) + glucose ≥ 200 mg/dL + symptoms (nausea, vomiting, abdominal pain) (Sibai 2014 PMID 24463678: DKA in pregnancy can occur at lower glucose 200-250 mg/dL vs > 300 non-pregnant); maternal mortality 0-15%, fetal mortality 9-35%(life-threatening)

5. Follow-up

Postpartum 75-g 2-h OGTT at 6-12 wk to reclassify (normal / IGT / DM per ADA 2025); lifetime DM2 risk 50-70% (Bellamy meta-analysis Lancet 2009 PMID 19465232; HR 7.43 for DM2 within 5 years); annual screening with HbA1c or fasting glucose per ADA 2025; DPP-derived lifestyle intervention (7% weight loss + 150 min/wk exercise reduces DM2 incidence by 58% per Knowler NEJM 2002 PMID 11832527); metformin consideration for IGT per ADA 2025; aspirin counseling for next pregnancy if PE history (USPSTF 2021 PMID 34581729)

6. Sources

Guideline: ACOG Practice Bulletin 190 (Gestational Diabetes Mellitus, 2018, reaffirmed 2024) + ADA Standards of Care 2025 Chapter 15 (Management of Diabetes in Pregnancy) + USPSTF 2021 universal screening (Davidson JAMA 2021, PMID 34374716) + IADPSG 2010 consensus (PMID 20190296) + Spong 2011 delivery-timing consensus (Obstet Gynecol 2011, PMID 21775849) + HAPO 2008 (Metzger NEJM 2008, PMID 18463375) + MIG 2008 (Rowan NEJM 2008, PMID 18463376) + ACHOIS 2005 (Crowther NEJM 2005, PMID 15951574) + CONCEPTT 2017 (Feig Lancet 2017, PMID 28923465) + DPP 2002 (Knowler NEJM 2002, PMID 11832527) + Bellamy 2009 (Lancet 2009, PMID 19465232) + Kim 2007 (Diabetes Care 2007, PMID 17290037) + Sibai 2014 (Obstet Gynecol 2014, PMID 24463678) + USPSTF 2021 aspirin (Davidson JAMA 2021, PMID 34581729)