Third trimester guide: weeks 28–40

Use these tools while you read—keep the same LMP or ultrasound anchor your clinician documented.

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Trimester labels are communication shortcuts. Your official gestational age may differ slightly if ultrasound adjusted dating, so week numbers on paperwork remain the precision layer underneath “first/second/third.”

Baby growth stages across third weeks

Educational charts describe organ milestones, length/weight averages, and movement timelines. Real fetal growth follows curves your clinician interprets with ultrasound and clinical context—not with fruit metaphors alone.

Common symptoms families discuss

Heartburn, shortness of breath, pelvic pressure, leg cramps, swelling, and stronger Braxton Hicks are frequent discussion points—your clinician should clarify what is expected for you versus urgent.

Prenatal care cadence & visit themes

Visit cadence often increases; Group B strep testing, growth checks, and birth planning intensify. Ask about signs of labor, when to call, and hospital preregistration steps.

Nutrition & supplement conversations

Smaller meals may help heartburn; continue hydration unless fluid-restricted for medical reasons. Discuss iron if fatigue worsens and anemia is suspected.

Pair trimester reading with the milestone list in our calculator after you enter dates. Screenshot your week string so partner apps stay aligned.

If you manage a chronic condition, bring your medication list to every visit—even if the topic page is about something unrelated like trimester milestones. Drug safety questions belong in a charted conversation, not a comment thread.

Nutrition pages should never shame food culture. If guidance here conflicts with your clinician’s advice for gestational diabetes, hypertension, or hyperemesis, follow the personalized plan—those conditions override generic tips.

This article is educational. It does not diagnose, treat, or triage emergencies. Always follow your licensed obstetric clinician, midwife, or local emergency guidance.