Hess's rule is useful for detection of:

Ans. b (Fetal age). (Ref. Textbook of FMT by Parikh 6th ed. 5.67)Hess's rule# CRL of embryo or fetus is based on Hess's rule, which states that square root of length of fetus in cm gives approximate age of fetus in months in first 5 months of pregnancy.# After 5 months it is length in cm/5= age (months).