Difference between fetus and embryo.

Every woman dreaming of replenishment in the family, seeing the long-awaited two strips on the test, is indescribable delight. Literally from the first days of pregnancy, she begins to take care of the future baby: she refuses bad habits, follows a diet, and reduces physical activity. However, not all ladies delve into the intricacies of the development of a tiny organism, limiting themselves only to studying images from an ultrasound scan. Meanwhile, being in the womb, the embryo goes a long way before turning into a full-fledged little man. In this article, we will look at how the fetus differs from the embryo.



Fetus - the human body developing in the womb after the laying of the main systems and organs. This term is used exclusively in relation to an unborn child. The considered period of development of the body is called fetal and begins when it reaches 8-9 weeks of age. This stage is characterized by intensive growth, differentiation of tissues, development of organs and systems, the end of the formation of membranes and placenta. A 38 week old toddler is considered full term. By this time, the fetus acquires signs of maturity: length from 47 cm, weight from 2500 g, bulging breast, pale pink skin without wrinkles, etc. Babies born between 28 and 37 weeks are considered premature, but at the same time quite viable. They require very careful care and are sometimes under the supervision of doctors for a long time. Ultrasound is recognized as the most effective method for diagnosing a fetus.


The embryo is a human embryo at the initial stage of its development until the moment it leaves the membranes. During this stage, a body is formed from the egg cell, which has certain morphological characteristics. This period lasts 8 weeks, after which the embryo is usually called the fetus. The embryo occurs as a result of the fusion of the nuclei of the egg with the sperm. At the end of the third week of development, a head and a primitive heart appear in the embryo, and after a few more days it begins to pump blood through the body and placenta. In the process of formation of the embryo, limbs and eyes, ears and rudiments of teeth are formed in it, gradually decreases, and then the tail disappears altogether. By the end of the eighth week, the process of laying the main vital organs practically ends.


Both of these terms denote a growing organism at different stages of development. The embryo is the name of the embryo from the moment of conception until the 8th week of pregnancy. The microscopic body appears in the ovum, which is an oval or round formation several millimeters in size. The yolk sac located inside it provides nutrition for the embryo. The ovum increases in size with the embryo. At the initial stage of formation, the embryo bears little resemblance to a person. It looks like a tiny twisted "worm" with a tail and without a pronounced head. Closer to 8-9 weeks in the embryo, limbs, eyes are indicated, the heart begins to beat and other vital organs are formed. The head becomes distinguishable, but disproportionately large in relation to the body. The maximum size of the embryo reaches only 3-4 cm, and the weight is about 5 g.

The main difference between the fetus and the embryo is the prenatal developmental age. As mentioned above, the embryo is the body that forms during the first eight weeks. Upon reaching this age, the embryo begins to be called the fetus. From now on, its nutrition is provided not by the yolk sac, but by the placenta - an organ located inside the uterus that communicates between the mother and the unborn baby. As he develops, he becomes more and more like a person. The body lengthens and acquires normal proportions, the limbs increase in size, the ears take their place on the sides of the head, etc. The fetus is actively growing and gaining weight. The weight of a full-term toddler is at least 2.5 kg, and the height is 47 cm.

To summarize, what is the difference between a fetus and an embryo.


Fetus Embryo
Ages from 8 weeksThe embryo from the moment of formation until reaching 8 weeks of age
Formed small organismParts of the body and internal organs are just beginning to develop
Feeding is carried out using the placentaFeeding is provided by the yolk sac
Outwardly resembles a tiny manLooks like a crooked "worm" with a tail and without a pronounced head
The growth of a full-term toddler is at least 47 cm, and the weight is 2.5 kgThe maximum size of the embryo reaches only 3-4 cm, and the weight is about 5 g