نظرة سريرية عامة
Naegele pregnancy dating is a structured clinical decision-support tool. It estimates gestational age and an expected delivery date from a reliable menstrual history. It standardizes calculation and communication, but its output remains an estimate that must be interpreted with the complete history, examination, laboratory method, imaging, serial trend, and institutional protocol. Enter contemporaneous data and verify units before relying on the result.
The displayed category reflects cohorts and conventional thresholds rather than a diagnosis or mandatory treatment instruction. Document inputs with the result, reassess when the patient changes, and prioritize time-critical stabilization over score completion. Discordance between the calculated estimate and clinical concern should prompt review of measurements, assumptions, competing diagnoses, and specialist advice.
دواعي الاستخدام
- Initial pregnancy dating from a reliable LMP
- Communication before ultrasound dating is established
القيود والسلامة
It assumes a 28-day cycle with ovulation near day 14 and is less reliable with uncertain dates, irregular cycles, or assisted conception. Performance varies with population, prevalence, disease stage, treatment era, and local laboratory reference intervals. Avoid extrapolation to groups excluded from validation, and do not use a low score to dismiss concerning symptoms or a high score to prove a diagnosis.
Clinical decisions should incorporate contraindications, comorbidities, patient preferences, and current regional guidance. Pregnancy, childhood, older age, critical illness, altered physiology, and organ failure often require population-specific interpretation. Clinipocket stores no entered patient values; record clinically relevant results in the approved medical record.
- Uncertain LMP, irregular cycles, recent hormonal contraception, lactation, or assisted reproduction require other dating methods
- Once an authoritative obstetric EDD is established, avoid casual redating
المعادلة
Naegele rule: EDD = first day of LMP + 280 days (40 weeks). Gestational age = elapsed days from LMP ÷ 7
تفسير النتائج
- <37 weeks — Preterm range: Delivery before 37 weeks is preterm. Assess symptoms and gestation-specific care.
- 37+0 to 41+6 — Term range: Early, full, or late term subdivisions apply. Follow antenatal plan and local timing guidance.
- ≥42 weeks — Post-term: Increasing surveillance considerations. Obstetric review according to protocol.
المراجع
- ACOG Committee Opinion: Methods for Estimating the Due Date.
- WHO recommendations on antenatal care for a positive pregnancy experience.
الأسئلة الشائعة
What if cycles are not 28 days?
LMP dating may be inaccurate; early ultrasound and the obstetric dating guideline should be used.
Should EDD change after every scan?
No. Once established using accepted criteria, the authoritative EDD should be documented and changed only under guideline-defined circumstances.
How is IVF pregnancy dated?
Use embryo age and transfer date according to assisted-reproduction guidance rather than LMP alone.