Updated: Nov 9, 2021
Pregnancy is a journey that is similar to a roller coaster ride one has long been waiting for. Consisting of a mix set of emotions, you might feel exhausted, restless and nauseated one day but once the excursion is over, you are left with the most memorable experience of your life.
It all starts with the appearance of those two red lines on the pregnancy test strip. Followed by an apparently, never ending series of severe emotional and physical changes, pregnancy and motherhood still remain to be among the most beautiful periods of a woman's life. The very thought of growing another human within your own body is both empowering and overwhelming at the same time. However, staying informed with what happens inside your own body and how does the development of foetus takes place inside the womb, makes it easier for you to keep track of your little one’s growth. A well informed mommy-to-be can better look after herself and her growing baby and can manage stress as well.
In gynaecology, the 9 month-pregnancy period is considered roughly equivalent to 40 weeks. Upon first examination of a pregnant woman, the very first thing an OB-GYN does is estimation of expected due date. It is usually calculated by marking the 40th week from the last period date of the woman’s menstrual cycle. A healthy full-term baby is usually expected to be delivered anywhere between 36-42 weeks.
The fetal development starts soon after conception within this 40-week period. The initial few weeks are considered critical as the vital organ systems start to develop during this period. Therefore, the use of antenatal vitamins such as folic acid is of paramount importance in the first trimester and should be continued throughout the pregnancy to ensure that the foetus is undergoing healthy development and is devoid of fetal anomalies. Baby growth and weight gain continues over the next few weeks. During the last few weeks, maturation of vital organs such as lungs takes place along with skeletal system development. Complete fetal development is a detailed topic and several books on embryology are solely dedicated to address the tiniest details on baby’s growth. However, in order to make it easier to digest for our readers, we have briefly reviewed the fetal growth and development process by each trimester below:
First Trimester (Week 1- Week 12)
First trimester is also referred to as embryonic stage since during these few weeks, the development of embryo takes place. The typical symptoms of early pregnancy are also experienced within these initial weeks. The development of placenta, which is the organ responsible for providing nutrition to the foetus throughout the entire pregnancy, also takes place during first trimester. Additionally, the development of major organ systems including reproductive system of the foetus also starts during this period. An ultrasound to verify fetal viability is also performed during this trimester.
Second Trimester (Week 13 – Week 24)
Also known as fetal stage, the second trimester baby becomes capable of moving, hearing and making facial movements. Fat deposition and maturation of liver and pancreas also takes place during these few weeks. A fetal anomaly scan is also performed during the second trimester, usually between 18-22 weeks.
Third Trimester (Week 25 onwards)
Final development and maturation of organs takes place during the third and final trimester. It is during this period that the baby starts to gain weight faster and prepares itself for birth by moving into a comfortable, baby-friendly position.