The first movements of the fetus and the appearance of hairs on the head are usually observed during the fifth month of pregnancy.
The mammary glands of the female undergo differentiation during pregnancy and start producing milk towards the end of pregnancy.
Trophoblast cells provide nutrients to the embryo and develop into the placenta. They are formed during the first stage of pregnancy and become the first cells to differentiate into extraembryonic structures that do not directly contribute to the formation of the embryo.
After implantation, a finger-like projection called microvilli appear on the trophoblast which is surrounded by uterine tissue and maternal blood and is required for the supply of nutrients.