The gestational age of a fetus can be estimated in the period from 10 to 30 weeks by examining the histology of abdominal skin.


Histologic Finding

Gestational Age

no appendages

10 weeks

crowding of nuclei in basal cells with budding

14 weeks

accumulation of mesenchymal cells below the developing hair bud

16 weeks

elongation of hair follicles with new bud formation

17 weeks

sebaceous glands present, and hair shaft visible

18 weeks

eccrine gland buds with oval nuclei

20 weeks

elongation of mostly solid eccrine ducts

23 weeks

early coiling of eccrine glands with lumen

25 weeks

coiling of eccrine glands seen as multiple transverse sections

30 weeks



• The gestational age is given from the last menstrual period.



• In 379 fetuses the authors had 97% agreement with the actual gestational age.



• Advanced autolysis may limit the histologic examination.

• Congenital skin diseases may affect the interpretation.


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