Haase rule

Haa·se rule

(hahs),
the length of the fetus in centimeters, divided by 5, is the duration of pregnancy in months, that is, the age of the fetus.
Farlex Partner Medical Dictionary © Farlex 2012

Haa·se rule

(hah'sĕ rūl)
The length of the fetus in centimeters, divided by 5, is the duration of pregnancy in months, i.e., the age of the fetus.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012