Separation of eyelids and formation of eyelashes is observed in the developing foetus

During 12 weeks (first trimester), organogenesis i.e., the development of the body organs takes place.

By the end of 12 weeks (first trimester), most of the major organ systems are formed, for example, the limbs and external genital organs are well developed.

During 17- 18 weeks (fifth month) first movements of foetus and appearance of hair on the head are usually observed.

By the end of about 24 weeks (end of second trimester), the body is covered with fine hair, eye-lids separate, and eyelashes are formed.