Pregnancy due date by last period: choosing the right “day one”

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

Pregnancy due date calculator · Due date by last period · Pregnancy week calculator · How many weeks pregnant · FAQ hub · How to calculate due date (blog)

Choose the first day of meaningful bleeding—not spotting alone—as LMP day one unless your clinician instructs otherwise.

If you are unsure, say so at intake; dating ultrasound may be scheduled earlier.

Open our LMP-focused calculator route to mirror the same workflow many pamphlets describe.

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.