Fetus development week by week

                                       Fetus development week by week

                                                                        Fetus

                                                                  development

                                                                  week by week

1st Weeks to 2nd weeks


During the first two weeks, the egg and sperm meet and create the zygote, which then becomes a blast cyst and attaches to the uterus wall. The embryo then begins to take on a more human-looking appearance.


3rd Weeks to 5th weeks


Around week 3, the brain, spinal cord, heart and gastrointestinal tract develop. During weeks 4 and 5, the heart begins to beat, blood begins to move and bones, eyes, ears and arm and leg buds begin to form. The brain also begins its own development, forming into five areas with cranial nerves.

                                                                              Fetus

                                                                                 Development

                                                                                  at week 4

6th Weeks to 7th weeks

In week 6, arm and leg buds have formed. Fingers and toes may be present, but they will often be webbed in structure. The lungs form and the brain grow. The seventh week is when nipples, hair follicles and organs begin to form.

                                                                          Fetus Development 

                                                                                 at week 8

8th Weeks to 12th weeks

During the eighth week, the face begins to form more, including eyelids, ears and other features. In the last three weeks of the first trimester, tooth buds appear and genitals become defined.

                                                                            Fetus

                                                                          Development 

                                                                                     at week 12

13th Weeks to 16th weeks


In the first three weeks of the second trimester, lanugos–or fine hair–begin to develop on the head of the fetus, bones harden, muscles develop and the fetus begins to move on its own.

17th Weeks to 19th weeks


The fetus gains the ability to hear and moves so much that the mother can feel it.


20th Weeks to 23rd weeks

Fetus Development at week 20

In week 20, lanugos can cover the whole body; nails, eyebrows and eyelashes appear; and the fetus’s heartbeat is strong enough to be heard with only a stethoscope. Weeks 21 to 23 of the fetus’s development are when fat begins to be stored, bone marrow makes blood cells and the airways in the fetus’s lungs develop further.


24th Weeks to 25th weeks


In the final two weeks of the second trimester, footprints and fingerprints form, the fetus gains a startle reflex and the lungs form air sacs.

26th Weeks to 28th weeks


In weeks 26 to 28, the brain, nervous system and respiratory system develop, and the fetus’s eyelids are able to open and close.

29th Weeks to35th weeks

                                                                          Fetus 

                                                                            Development

                                                                               at week 30

During weeks 29 to 35, the fetus stores more body fat, the bones finish developing and breathing movement occurs, even though no true breathing is occurring.

36th Weeks


By week 36, the fetus is almost fully developed and can be born with no medical complications, although some are still possible depending on individual differences in development. In week 36, lanugos begin to slough off, and fingernails grow to the ends of the fingertips.


37th Weeks to 41st weeks


During the final three weeks, only small changes occur, such as the further shedding of lanugos, growth of fingernails and growth of hair on the head.

Fetus 
Development
    at week 38