ObstetricsBeginner

Estimated Due Date (EDD)

Calculates the Estimated Due Date (EDD) using Naegele's rule.

Clinical Parameters

3 Variables

Awaiting Clinical Parameters

Configure the patient variables on the left and select Calculate Result to generate the clinical score and stratification.

Verified 2026 GuidelinesInstant Calculation
Jump to Formula & Clinical Protocol ↓
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High Yield Prometric TopicObstetrics & Gynecology

Tested on Gulf Medical Boards (DHA, SMLE, MOH & HAAD)

Clinical calculations and diagnostic scoring systems like Estimated Due Date (EDD) frequently appear on Prometric exams. Master high-yield clinical vignettes with instant AI-powered pathophysiology rationales.

Clinical Significance & Diagnostic Standard
2026 Clinical Reference

What is the Estimated Due Date (EDD)?

📋Clinical Summary & Definition Capsule

The Estimated Due Date (EDD) is an evidence-based clinical decision rule engineered to quantify diagnostic probability, stratify clinical severity, and guide therapeutic decision-making in obstetrics & gynecology practice. Calculates the Estimated Due Date (EDD) and current gestational age based on the first day of the Last Menstrual Period (LMP) using Naegele's rule (LMP + 280 days). Clinical scoring tools like Estimated Due Date (EDD) are essential in acute and outpatient management, enabling clinicians to objectively differentiate between low-risk candidates suitable for conservative therapy and high-risk patients requiring urgent interventions. Verified against current 2026 clinical standards, this tool is extensively tested on Gulf health authority licensing exams including DHA (Dubai), SMLE (Saudi Arabia), MOH, HAAD/DOH (Abu Dhabi), OMSB (Oman), and QCHP (Qatar).

💡Clinical Pearls & Diagnostic Utility

Establishing an accurate EDD is essential for optimal prenatal care, scheduling screening tests, and timing of delivery.

Mathematical Formulation

Formula & Calculation Parameters

The mathematical equation and clinical variables required to calculate Estimated Due Date (EDD):

Naegele's Rule: EDD = First day of LMP + 280 days (40 weeks).
Risk Stratification

Score Interpretation & Clinical Stratification

Score RangeClinical InterpretationRisk Tier
≤ 36Pretermorange
37 – 41Termgreen
≥ 42Posttermred
Clinical Limitations & Contraindications

When to Exercise Caution

Naegele's rule assumes a standard 28-day menstrual cycle with ovulation occurring on day 14. First-trimester ultrasound is the most accurate method for establishing or confirming gestational age.

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Medical Review & Guidelines Compliance
MD

Clinical Review Board

Dr. Muhammad Nouman, MBBS

Capital Medical University | PMDC Reg No: 117744-P

Clinical Audit Status

✓ Verified for 2026 Guidelines

Last updated: 2026-08-07

Peer-Reviewed Medical Literature

  • Naegele FC. Lehrbuch der Geburtshülfe für Hebammen. 1812.
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