The 3 Stages Of Prenatal Development


For most of us, a child starts growing after he gets a few months old and we can see the changes in our own eyes. But, the prenatal phase is also an important portion of a child’s development. It pretty much lays down the very foundation of the child’s mental growth, as the brain continues to grow throughout the childhood, too.

Prenatal Baby Development Stages

The prenatal period stages are divided into three major ones. These are the most important prenatal stages of human development for a baby.

1. Germinal Stage

This is where the conception takes place. The sperm of the father and the egg of the mother combine together, inside a fallopian tube of the mother. This egg then gets fertilized and is termed as the zygote. It journeys gradually towards the uterus, taking over a week’s time to reach there, and then the process of growth begins. The cells divide due to mitosis and the first steps of the baby’s formation begin.


The cells present in the inner section lead to the formation of the embryo, while the cells in the outer section develop to form the placenta. This division continues and forms a blastocyst, which in itself, is made up of three portions.

The cells which develop to form the nervous system and the skin of the baby are termed as ectoderm. The cells which develop to form the respiratory and digestive systems for the baby are called endoderm. The other cells are called mesoderm, and they form the skeletal and muscular systems. This blastocyst then attaches itself to the wall of the uterus, during implantation.

A successful implantation interrupts the menstrual cycle in the woman, which leads one to check if they are pregnant or not.

2. Embryonic Stage

The cells that have grown until know, together constitute the embryo. This growth keeps happening until the entire mass of cells now starts resembling a vague shape of a human being. This is also where the first steps of the brain’s development begin.

Primarily, the formation of a neural tube takes place first. Multiple ridges start forming along the neural plate which leads to the creation of a hollow tube-like structure. This later develops into the creation of the spinal cord and the brain. The tube closes and brain cells start developing inside, forming the foremost, middle, and rear sections of the brain.

The head also begins to form rapidly as the first signs of facial features start showing themselves. A single blood vessel that later grows to become the heart starts pulsating lightly.

This is then followed by formation of the limbs, roughly around 5 weeks into pregnancy. By 8 weeks, the embryo has nearly most of the basic organs a human being needs to function, but its gender still remains undetermined. Neural networks begin to form around 6 weeks as neurons first start appearing and move to different areas of the brain to form the connections.


3. Foetal Stage

Around the completion of 9 weeks of pregnancy, the growth of the embryo finally reaches a stage where it then is referred to as, a foetus.

The growth from here on continues right until delivery of the baby. The body systems continue developing and strengthening within the baby. Neural networks and synapses begin to develop with brain development at an all-time high. Gradually, the foetus starts making movements using its limbs, too.

On completion of 3 months of pregnancy, the genitals begin to form properly and by the end, all organs have developed fully. The height and weight of the foetus keep increasing throughout.

As the second trimester of the pregnancy begins, the heart gets stronger and one can hear the baby’s heartbeats clearly. Smaller features such as hair, eyelashes, nails, start appearing on the baby. In this trimester, the growth of the foetus is rather exponential and becomes nearly six times larger than before.

Throughout this period, the development of a brain takes place rapidly and the nervous system begins to respond to the growth of the foetus. In 28 weeks of pregnancy, the brain activity resembles that of a sleeping baby. Following this until birth, the baby keeps growing and the lungs start to expand and contract, preparing the body to breathe after birth.


Common Problems During Prenatal Development

The foetal period of prenatal development is of intense growth and, hence, is very sensitive to other conditions. There are the general problems one might observe during this stage.

1. Genetic Problems

As the baby grows, there are chances of some abnormal formations or development issues in the physical aspects of the child, across multiple organs. It could be due to a genetic mutation, gene damage, abnormality of chromosomes, and so on. This could descend primarily from the parents. However, certain cases have shown that these could arise by themselves during the prenatal stage.

These abnormalities could range from being dismissively minor to absolutely fatal. Chances of miscarriage at this stage are roughly 10-15%, mostly caused by these abnormalities.

The age of the mother plays a pivotal role in these situations. Younger mothers tend to have healthier kids. For mothers over 35 to 40 years of age, their kids are highly susceptible to Down’s syndrome, as well as other pregnancy-related complications.

Presence of any illnesses or diseases in the mother plays yet another factor in hampering prenatal development. An HIV positive mother can pass the virus to her child. Other viruses such as rubella, result in the baby having a defective heart or being born deaf.

Throughout pregnancy, it is essential for the mother to keep a balanced and nutritious diet that contains all the vitamins and minerals that are needed. Certain supplements for folic acid, calcium, iron, zinc, and other nutrients are recommended to keep their proportion adequate for the mother as well as the baby. Deficiencies in them can result in an incomplete growth of the foetus or even defects in the neural tube, resulting in an ill-developed brain. Furthermore, the mother and foetus should avoid exposure to any substances like alcohol, illegal drugs, or any medications, that directly affect the foetus and lead to multiple malformations.

2. Prematurity

In many cases, a baby might be born prematurely, failing to complete the entire cycle of growth through 40 weeks of pregnancy. Due to advances in medical sciences, most premature babies can stay alive and catch up with the development after birth, too. The survival rate of a baby increases, based on a larger time spent inside the womb.

Duration (in Weeks) Survival Rate (in Percentage)
Less than 21 0
21 – 22 0 – 10
22 – 23 10 – 35
23 – 24 40 – 70
24 – 25 50 – 80
25 – 26 80 – 90
26 – 27 and more More than 90



Risk in Prenatal Period

Here are some of the risks in the prenatal period that need attention.

  • Malnutrition: Nutrition and a balanced diet are of prime importance in the prenatal period, since the growth of the baby is at an all-time high. Any reduction in the nutrition of the mother affects the infant as well. This leads to the formation of a foetus that is small in size, which also affects the development of various body organs and immune systems as well as nervous systems.
  • Pollutants: Exposure to various environmental pollutants can also mean problems for the foetus. Certain pesticides or aerosols can contain chemicals that harm the natural growth of the infant.
  • Marijuana: Marijuana can be used for therapeutic purposes as recommended by some doctors in certain areas or for recreational purposes. Marijuana, however, stays inside the fat cells of the body after consumption, for approximately a month. If it is still present during conception or is consumed in the initial stages of prenatal development, it can affect the growth cycle of the baby.
  • Alcohol: All mothers are strongly advised to ditch the bottle prior to pregnancy itself. And during pregnancy, consumption of any kind of alcohol is highly forbidden. If a mother ends up consuming alcohol while being pregnant, it can result in a fetal alcohol syndrome. This is an array of birth-related complication and defects in the baby. The infant could end up being retarded and have extremely low body weight. Their facial features can be ill-formed, such as having a flat nose, extremely wide eyes, no philtrum present on the upper lip or extremely thin lips.
  • Cocaine: Cocaine, in general, is quite a potent drug and has long-term effects on the body which can be quite harmful. If a mother is exposed to cocaine or chooses to consume it, the infant can result in having extreme behavioural problems. The baby can be hyperactive, extremely oversensitive to external environments or even anybody holding them, and could also suffer from mental retardation.
  • Tobacco: All women are strongly advised to stay away from smoking as well as reduce any possible exposure to second-hand smoke from external factors while they are pregnant. Mothers who continue smoking have an increased risk of pregnancy issues and miscarriage as well. There can be further birth complications in the child.
  • Amphetamines and Tranquillizers: These are the worst of them all and can cause long-term damage to the foetus, leading to severe retardation or extensive complications during birth.

The prenatal stage is extremely critical for any child. The majority of physical and psychological development takes place during this stage, preparing the child to live by himself once he is born and out into the world. When any problems or issues occur, it is important to understand the reason behind its occurrence and what actions can be taken. Preventive measures are always better than actions to counter the problems already afflicted.

Even after birth, the infant continues to develop and grow, and it is important that they are not exposed to any of the factors even then. The brain development is still taking place and it is important for that to continue unabated without any issues, to have a child that is strong, independent, and healthy like his peers.