Nägele's rule

System: Pregnancy & Women's Health Signs · All pregnancy & women's health signs

What it is — and how it is elicited

A calculation of the estimated delivery date: take the first day of the last menstrual period, add seven days, subtract three months and add a year.

What a positive finding suggests

The standard first estimate of the due date (EDD) in pregnancy, assuming a 28-day cycle.

◈ Behind the name

Franz Karl Naegele (1778–1851), German obstetrician.

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Please note: This page is an educational reference about clinical examination signs. A clinical sign supports — and never replaces — a full clinical evaluation, examination and appropriate testing. A sign being present does not by itself prove a diagnosis, and an absent sign does not rule one out. If you have symptoms that worry you, see a health professional.