Pregnancy period (gestational age)
The period between the last menstrual cycle and the childbirth is known as the pregnancy period. Usually, it lasts about 40 weeks.
The period between the conception and the childbirth is the gestation period. Gestation period is about 38 weeks.
Embryonic period and foetal period
The period up to the end of the eight week of gestation is called the embryonic period. The foetal period starts from the end of the embryonic period and lasts about 30 weeks.
The embryonic period
Fifth week of pregnancy (third week of gestation)
- Central nervous system, (the brain and the spinal cord) and the heart start to develop.
- Development of the digestive system starts during the fifth week of pregnancy.
Sixth and seventh weeks of pregnancy (fourth and fifth weeks of gestation)
- The eyes and ears start their development.
- Buds of the limb (the arms, and legs) are visible now.
- The brain and some cranial nerves grow further.
- Initial development of the backbones (vertebrae) and other bones occurs.
- The heart grows further and beats regularly. Immature blood flows through major blood vessels.
Eighth week of pregnancy (sixth week of gestation)
- The lungs start their development.
- The brain grows further.
- The buds of limbs grow longer.
- The hands, feet, fingers, and toes are visible now.
Ninth week of pregnancy (seventh week of gestation)
- All organ systems have started their development at this stage.
- Elbows may be visible.
- Hair and the nipple development start.
Tenth week of pregnancy (eighth week of gestation)
- Visible part of the external ear starts its development to original shape.
- The eye lids and other facial features grow further.
- The bowels rotate.
About Pregnancy: Symptoms and Diagnosis of Pregnancy
About Pregnancy: How a Baby Is Conceived?
About Pregnancy: How to Manage Your Weight?
About Pregnancy: Benefits of Exercise During Pregnancy and Cautions
About Pregnancy: Pregnancy by Weeks - Part 1
About Pregnancy: Pregnancy by Weeks – Part 2
About Pregnancy: Pregnancy by Weeks – Part 3
About Pregnancy: Pregnancy by Weeks – Part 4