Implantation and early stages of fetal development

Abstract

Embryo implantation is a three-step process; apposition, adhesion, and invasion. The physiological and molecular pathways during the implantation process are complex and highly organized. The complex multisteps of implantation are initiated when the developing embryo first makes contact with the epithelial cells of the uterus. The outcome of pregnancy depends on the implantation of the embryo in a receptive endometrium. After successful implantation, the embryonic period that begins with fertilization ends in the 9th week. The fetal period begins at the beginning of the 9th week. During this period, the growth rate of the head has slowed compared to the rest of the body. Fetal length growth occurs especially in the third, fourth, and fifth months; and weight gain begins to be mainly observed in the last two months of pregnancy. In this headline, the previously mentioned stages are comprehensively discussed. © 2023 Nova Science Publishers, Inc. All rights reserved.