Prenatal growth and development are very important in the development of a child. The prenatal stage refers to the period from conception to childbirth. The period can be divided into three trimesters of the pregnancy, including; pre-embryonic period, embryonic period, and fetal stages. During these periods, the fertilized egg develops from a mass of cells to a fetus with organs functioning awaiting childbirth. Prenatal growth and development set the stage for the child’s future psychological and physical development after birth. Growth, in this case, is defined as the process where cells increase in number and size. On the other hand, development is referred to as the increase in functionality of those cells, genes, and tissues that were not functioning. Growth and development are achieved through differentiation. The paper analyzes fetal growth and development from conception to childbirth and explaining the significance of each step.
Keywords: Prenatal, Growth, Embry, Fetus, and Development
Table of Contents
The prenatal period refers to that period between conception and childbirth. Most people think that the development of the child begins in infancy. However, the prenatal period is also an essential part of the process of development. Prenatal growth and development set the stage for psychological development in the future. During the prenatal period, there is brain development, which continues to grow through several changes during early childhood (Cherry, 2020). There are three phases in prenatal growth and development. This research paper has been prepared to analyze prenatal growth and development.
According to Raznahan et al. (2012), growth refers to an increase in size, resulting in existing structural and functional units increasing. On the other hand, development refers to systematic switching on and off related to certain genes (Jeffery and Spoor, 2004). Growth is attained by anabolic processes preponderance where living cells utilize operating genes to increase in number. Differentiation then occurs in genes that previously were not operating. Organs then increase in size through cellular hyperplasia and hypertrophy.
In Embryonic and fetal development, a fertilized oocyte changes to become a complete organism representing the specie that produced the oocyte. Genes determine growth and development, and all the cells in humans are made up of the same genetic make-up under the same conditions (Jeffery and Spoor, 2004). In growth, the basic mechanisms include; increase in the number and size of the cell and extracellular substances. The mitotic division is responsible for the increase in cell numbers. Under the mitotic division, some cells are life-long proliferating; that is, they divide throughout the lifespan of an individual (Cherry, 2020). Some cells undergo terminal differentiation and only divide during certain occasions of an individual’s life. The prenatal period in humans is divided into three; pre-embryonic, embryonic, and fetal.
The pre-embryonic stage is also referred to as a terminal stage. The stage begins at conception, where the egg and the sperm meet and unite in the fallopian tube. When the two unite, they form a zygote, which is a fertilized egg (Jeffery and Spoor, 2004). The zygote is single-celled, and it immediately beings it journeys to the uterus from the fallopian tube. Between 24 to 36 hours after the fertilization, the zygote starts to undergo cell division. The process of division is called cell mitosis (Cherry, 2020).
A significant percentage of zygote hardly goes past this stage of cell division. When the zygote attains eight numbers of cells, the differentiation process kicks in. The cells pick certain characteristics that will eventually determine what it will become. The cells multiply and then separate into two distinct mass. The inner cells become the embryo, while the outer cells from the placenta. In the journey from the fallopian tube to the uterus wall, the cell division rate is very fast. At this stage, these cells develop into a blastocyst.
There are three layers in a blastocyst that develop into different body structures (Cherry, 2020). The first layer is the nervous system, and the skin referred to as ectoderm. The second layer consists of the respiratory and digestive system, referred to as endoderm, and the third layer is referred to as mesoderm that consists of skeletal and muscle systems. Implantation occurs when the blastocyst reaches and attaches to the uterine wall. The blastocyst will nestle on the uterine wall and rupture blood vessels. Membranes and blood vessels form between the blastocyst and the uterine wall forming a web of blood vessels. The connection of blood vessels will supply nutrients for the next nine months until a child is born. It is important to note that implantation is always sure or automatic process (Jeffery and Spoor, 2004).
According to Cherry (2020), nearly 60% of all naturally occurring conceptions occurring fail to implant on the uterus successfully. The formation of new life ends before the mother is aware of the pregnancy. When implantation is successful, the mother will experience changes in hormones that stop the menstrual cycle and cause other physical changes. Some of these physical changes may act as a natural way of protecting the new life.
After successful implantation, the mass of cells is referred to as the embryo. The embryonic phase begins three weeks after the conception process. At this phase, the mass of cells has acquired distinct characteristics as human beings. The embryonic stage plays a crucial role in the development of the brain. Neural tubes begin to develop in the 4th week after conception (Raznahan et al. 2012). The neural tube later develops to become the central nervous system that consists of the brain and the spinal cord. When the neural tubes are developing, two ridges will emerge on both sides of the neural plate. As time progresses, more ridges will emerge as they fold inwardly to form a hollow tube. Once the development of the hollow tube is complete, cells begin to form close to the center of the tube. Brain vesicle begins to form when the tube closes, and the vesicles will develop into different parts of the brain that include fore, mid, and hindbrain (Cherry, 2020).
The head begins to form four weeks after conception, and this followed by the eyes, nose ears, and mouth. At this point, blood vessels that will later form the heart begin pulsing. On the 5th week, buds that will later develop into legs and arms start to appear. When the embryo gets to week eight, all the basic organs have developed except for the sex organs. At this point, the embryo measures one inch and weighs one gram. At the end of the embryonic phase, the central nervous system’s essential structures and the brain have developed (Raznahan et al. 2012). Also, the peripheral nervous system structure has been established at this point. Forty-two days after conception, the production of brain cells or neurons begins the will be completed around the middle of the pregnancy. As the production of the brain cells occurs, they move to occupy various parts of the brain (Jeffery and Spoor, 2004). The neurons move to their correct location, then begin forming connections with other neurons. The connection establishes a network for rudimentary neural.
At this stage, the differentiation of different cells is almost complete. The embryo now enters into the fetal stage. In this stage, prenatal development marks another important step in the form of changes in the brain. The stage takes place from the 9th week to birth. Growth and development are remarkable in this phase (Jeffery and Spoor, 2004). Structures and body systems established in the embryonic stage continue to develop in this phase. Neurons, spinal code, and the brain all develop from the neural tube. Synapsis forming connections between neurons start to develop in this stage as more and more neurons that have been formed move to the correct locations.
Reflexes begin emerging between the 9th and the 12th week of gestation. Sex organs begin differentiation in the third month of gestation. And by the end of this month, differentiation is complete, and all the body parts are completely formed. At the end of this period, the weight of the fetus is three ounces from this point, growth and development shifts to length and weight. Major physical growth occurs later in the pregnancy (Raznahan et al. 2012).
The first three months are referred to as the first trimester of the pregnancy. From the fourth month to the sixth one-second trimester- of the pregnancy, different body systems develop further, and the heartbeat grows significantly. In the second trimester of the pregnancy, the eyelashes, fingernails, toenails, and hair begin to form, and the size of the fetus reaches six times (Dorscheidt, 2010). The second trimester is also the most important part of the prenatal as the brain, and central nervous systems further develop. The central nervous system and the brain begin to become responsive.
On the 28th week of the pregnancy, the maturity of the brains becomes faster, and the activities in the brain start to resemble that of a child who is sleeping. Seven months into the pregnancy, the fetus’s development continues as it gains weight and makes preparation for life outside the womb (Dorscheidt, 2010). The breathing muscles begin preparation as the lungs expand and contract. Development and growth in the womb will follow this normal pattern. However, there are situations when this is not followed because of certain factors such as malnutrition, prenatal influences, and diseases that affect brain development at this crucial moment. The development of the brain does not end at childbirth and continues into the postnatal period (Raznahan et al. 2012). Premature tubal or uterine activities may result in abortion of the fetus during the embryonic or fetal stage. Sometimes abortion is done by medical experts.
Prenatal development is that stage between conception and childbirth. Prenatal development and growth are characterized by major changes that prepare the organism for a new life. Prenatal growth and development can be divided into three trimesters of the pregnancy, each having unique growth and development. After fertilization, which takes place in the fallopian tube, a zygote is formed, which then begins its journey to the uterine wall. The journey is characterized by faster cell division to form a mass of cells. The zygote moves and attaches itself to the uterine wall. The first stage is the pre-embryonic phase. A significant number of zygote fails to attach to the wall, and most women fail to notice this. The second phase of prenatal growth and development is the embryonic phase, where the embryo undoes significant development of major body structures. The final face, which is also the final trimester of the pregnancy, is called the fetus stage. The important development of the brain takes place in this stage. The fetus’s sex organs develop in this stage as it starts to prepare for the life outside. An embryo may be aborted between embryonic and fetus stage due to premature tubal or uterine activities. The baby begins to make reflexes in this stage. Factors such as diseases may alter the normal development of the fetus and the brain.
Cherry, K., 2020. How A Baby Develops During The Prenatal Period. [online] Verywell Mind. Available at: https://www.verywellmind.com/stages-of-prenatal-development-2795073
Dorscheidt, J., 2010. Developments in legal and medical practice regarding the unborn child and the need to expand prenatal legal protection. European Journal of Health Law, 17(5), pp.433-454.
Jeffery, N. and Spoor, F., 2004. Prenatal growth and development of the modern human labyrinth. Journal of Anatomy, 204(2), pp.71-92.
Raznahan, A., Greenstein, D., Lee, N.R., Clasen, L.S. and Giedd, J.N., 2012. Prenatal growth in humans and postnatal brain maturation into late adolescence. Proceedings of the National Academy of Sciences, 109(28), pp.11366-11371.