Dr. Cosmina Brummer
Obstetrica - ginecologie
A week-by-week pregnancy calendar
Week 1 : the average crown length is 0.5mm;
Week 2 : the average crown length is 2 mm ;
Week 3 : the average crown length is 3 mm ;
Week 4 : the average crown length is 4 mm and the average weight of foetus is 0.4 g ;
Seven days after ovulation, the fertilized egg gradually implants itself in the uterus . By the 10th day , the embryo appears . Its inner cells form two, and later , three layers . The first grows into the skin , eyes , brain and nerve centre ; the second , the foetal digestive organs and the lungs ; while the third , its blood , muscles , heart and bones .
Week 5: the average crown length is 5-8mm ;
Week 6 : the average crown length is 10-14 mm ;
Week 7 : the average crown length is 17-22mm ;
Week 8 : the average crown length is 28-30mm and the average weight of foetus is 2g ;
The first heartbeat . Larger organs begin to take shape and form as the brain , facial features and limb joints become visible . Finally , pregnancy can be confird by sonar .
Foetal phase :
Week 9 : 10 g and 5 cm ;
Week 10 :
Week 11 :
Week 12 : 19 g and 8cm .
Now known as a foetus , and with a defined gender - its ears , nose and mouth take form on its relatively large head . The newly shaped eyes are covered with a skin that will soon become the eyelids . Arms and legs lengthen as the nails begin to grow . The foetusâ€™s heart now beats as just 170-175 per minute .
Week 13 : 9 cm ;
Week 14 : 45 g ;
Week 15 :
Week 16 : 100 g and 14 cm ;
Large organs now fully formed . Coordinated by its brain , the foetus can now stretch its arms and legs , and open its mouth - in which 20 little teeth are already in place . Its face becomes more defined while the rest is covered with soft downy hair known as lanugo .
Week 17 : 15 cm ;
Week 18 : 200 g ;
Week 19 :
Week 20 : 300 g and 19 cm .
Hair begin to grow . The foetal eyes are still shut even as little eyelashes appear . Fingerprints are formed . Fluttering or stirring may now be felt from the growing foetal body movements . These are all important signs in a pregnancy , so make a special note of this day .
Week 21 : 20 cm ;
Week 22 : 460 g ;
Week 23 :
Week 24 : 600 g and 23 cm ;
Muscle and nerve connections begin forming . A layer of fat gets deposited under a red wrinkled skin and most of the foetal weight is gained ; maturation begins , and with it , early breathing practices and the experience of touch . The foetus can now hear music and words spoken outside .
Week 25 : 24 cm ;
Week 26 : 820 g ;
Week 27 :
Week 28 : 1100 g and 27 cm ;
Lungs take their first breath . Eyelids slowly open revealing the eyes . A cycle of sleeping and waking begins . A heartbeat now is clearly heard with a stethoscope . Foetus can now experience taste as its papillae are fully formed . Its skin is now covered by vernix .
Week 29 : 28 cm ;
Week 30 : 1300 g ;
Week 31 :
Week 32 : 1800 g and 30 cm ;
Hair on the head grows longer . The foetus begins to focus its vision as its eyebrows and eyelashes become fully developed . Active breathing . Lanugo disappears from the face and the soft skin becomes a little less wrinkled as a layer of fat thickens .
Week 33 : 31 cm ;
Week 34 : 2100 g ;
Week 35 :
Week 36 : 2200 g and 34 cm ;
The foetus adopts the shape of a ababy with its head now proportionate to its body . Eye focus and blink and become light sensitive . Organ system are now working . Fingernails are fully formed as lanugo disappears from the body and ear cartilages soften . Well-shaped contours are now apparent as a result of the layer of subcutaneous fat .
Week 37 : 35 cm ;
Week 38 : 2900 g ;
Week 39 :
Week 40 : 3200 g and 36 cm ;
During the last two months of the pregnancy , fifthy-percent of the babyâ€™s full term weight will be reached . The head is now firm and has the largest circumference of all body parts . The vernix will now disappear from the skin .