The Fetal Development in Early Trimester

Written by: Amicis

Pertumbuhan Janin Pada Trisemester Awal

Pregnancy period is divided into three trimesters, namely the first trimester, second trimester and third trimester. The first trimester of the pregnancy period occurs during 12 weeks starting from the first day of Mommy’s last menstruation period. 

For most Mommies, pregnancy period is a moment of magic, happiness, a great sense of curiosity, as well as a very vulnerable period for the fetus. To eliminate the curiosity of Mommy during early pregnancy, Mommy may read the following information regarding the fetal development during pregnancy in the first trimester. 

Fertilization and Implantation

After the ovum is mature, it is ready to be fertilized by a sperm. When fertilization occurs, the ovum will then be attached to the uterine wall and automatically the lining of the uterus will continue to thicken from time to time. 

The fertilized ovum will then continue to divide and grow. This process is called implantation. At the time of implantation, the placenta or fetal placenta has begun to take shape. The function of the placenta is to distribute food juices and oxygen to the fetus.

Week 4 to Week 6

At Week 4, Mommy may realize that Mommy’s menstrual period is late by two weeks. After Mommy is confirmed pregnant, the Obstetrician will estimate that the age of the fetus is about four weeks. 

At the age of four weeks, the fetus has already had a spinal tissue. This tissue is composed by three layers which later will form the vital organs contained in the baby’s body when the fetus is growing up. 

At Week 6, Mommy can already hear the fetal heartbeat through Doppler and Mommy can also see the fetus through ultrasound visualization. At this age, the arms and legs have started to appear even though only a branch.

At two months of pregnancy, the fetus is experiencing rapid growth and development. At the end of the second month, the fetus has already had all the vital organs of the nerve system so that the fetus already looks like a mini baby.

This two-month-old fetus has a length of about 2.5 cm and securely attached to the wall of the uterus. And at the age of 3 months, the fetus has already had complete organs and nerve system which already function properly as adults. 

At this age, the fetus also has the ability to move, especially the hands and feet as well as being able to open and close his mouth. Because the movement is soft and light, Mommy cannot feel it. The hair and his fingers start to grow. The fetal length is about 10 cm, can be seen through an ultrasound device.