Fetal Week by Week Development
Three (3) Weeks
On the third week after conception, the baby, still a human embryo, is about two millimetres long. The brain, heart and gill arches (part of the embryo which will later develop as the baby’s face, throat and inner ear) are starting to develop and take their shape.
Four (4) Weeks
Now the human embryo has grown about 6 millimetres long. The brain and the backbone are continuously developing. The heart is now starting to pump blood to other developing organs of the body such as the liver. By this time, ribs are starting to develop around the rudimentary lungs.
Five Weeks
The wonderful development going on inside the womb is now starting to become visible in the mothers belly. During this stage of the fetal week by week development, the foetus inside its newly formed sac is starting to take shape.
Six Weeks
The foetus would be about 15 millimetres long. Arms and legs are staring to form but are still visibly short. The head, chest and abdominal cavity is developing rapidly at this stage. Spinal column is now properly formed. By the end of 6th week the first heart circulation starts its process.
Seven Weeks
The foetus’ eyes and ears are starting to form but are still under a skin covering. Liver and kidneys are formed but not yet fully functional. During this particular stage of the fetal week by week development, the umbilical cord serves as a large blood vessel that transports oxygenated blood to the foetus and carry deoxygenated blood from the foetus to the placenta.
Heart is now starting to pump blood adequate enough to transport oxygen and cells through blood vessels.
Eight Weeks
During this time the foetus is now about 4 centimetres long. The baby is still just about one and a half inches but all bodily organs are formed and in place.
Every organ and body part that can be found in a fully grown human being has now been fully developed.
Ten Weeks
Baby’s eyes are more recognizable. Ears, specifically the inner part of ears are now formed. The face is much clearer by the 10th week.
Eleven Weeks
Baby’s form is more recognizable although the head is still slightly larger for the body and the limbs are shorter. Eyes and ears are now completely formed and functional. Fingers and toes are now formed but are still linked together. The external genital organ starts to form and develop, while ovaries/testicles are already formed.
Twelve Weeks
Almost all the vital organs and body parts are formed and most of them by this time are functional. 12 weeks onwards can be a critical stage since inborn or congenital abnormalities may occur if the developing process of baby’s organs are halted or interfered by any outside factors.
It is less likely to have a miscarriage during this time since the foetus is fastened into the mother’s uterus.
During this late stage of the fetal week by week development, the foetus can jerk or move suddenly, can experience hiccups, and can start flexing arms and tiny legs.
