What important developments will the foetus undergo in first trimester?

During the first trimester of pregnancy, the foetus undergoes rapid and significant development. Here are some important developments that take place during this crucial phase:

Week 1-4: Embryonic Stage:

- The fertilized egg, known as a zygote, undergoes cell division and develops into an embryo.

- The embryo implants into the uterine wall, and the placenta and umbilical cord begin to form.

- The basic structure of the body, including the brain, spinal cord, and organs, starts to develop.

Week 5-8: Early Foetal Development:

- The embryo is now referred to as a foetus.

- The heart forms and starts beating, and the circulatory system begins to function.

- Limbs start to develop, and fingers and toes appear.

- The facial features become more distinct, and the eyes, nose, and mouth start to form.

- The foetus is highly vulnerable to environmental factors and toxins during this stage.

Week 9-12: Rapid Growth and Organ Formation:

- The foetus grows rapidly in size, and the major organs continue to develop.

- The bones start to harden, and muscles become more defined.

- The respiratory system begins to develop, and the foetus starts to make small breathing movements.

- The sex organs start to differentiate, and the gender of the foetus can often be determined.

- The foetus starts to produce urine, and the kidneys begin to function.

By the end of the first trimester, which is around 12 weeks of gestation, the foetus has all of the major organs in place. It is about 3 inches (7-8 cm) long and weighs approximately 1 ounce (30 grams). From this point onwards, the foetus will continue to grow, mature, and develop its various systems in preparation for birth.