After attachment of trophoblast, the uterine cells divide rapidly and covers the blastocyst. As a result, the blastocyst becomes embedded in the endometrium of the uterus . This is called implantation and it leads to pregnancy.  After implantation, finger-like projections appear on the trophoblast called chorionic villi which are surrounded by the uterine tissue and maternal blood.The chorionic villi and uterine tissue become interdigitated with each other and jointly form a structural and functional unit between developing embryo (foetus) and maternal body called placenta. The placenta facilitate the supply of oxygen and nutrients to the embryo and also removal of carbon dioxide and excretory/waste materials produced by the embryo.

During which month the first movements of the foetus is noticed ?

During the fifth month.

By the end of the second month of pregnancy, the foetus develops limbs and digits.

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 welldeveloped.

The first movements of the foetus and appearance of hair on the head are usually observed during the fifth month.