Broadly speaking, the phase formation of the fetus in the uterus has three stages, according to medical terms is called a pre-embryonic phase, the phase of embryonic and fetal phase. Pre-embryonic phase experienced during the first trimester.
First Month
Early Sunday was still counted during menstruation, conception has not even lasted. This calculation is performed to determine pregnancy. The second week, 46 chromosomes fused in the process of fertilization, the egg cell has been filled sperm winner. Fertilized egg cell that has been split in two, 30 hours after fertilization. While continuing to divide, move the egg in the hole tubes toward the uterus. After splitting into 32, the egg is called morula. The third week, cells began to grow and is divided roughly twice a day so that on the 12th day the number has increased and formed blastocyst adrift on the endometrium. Fourth week, the fetus has become an embryo that produces the hormone chorionic gonadotropin (HCG), whereby when the mother's urine tested by using a pregnancy test will show positive results. 3-month fetus requires adequate nutrition for brain growth and organ of the maximum.
Second Month
Fifth week, the fetus continues to grow to 1.3 mm. Central nervous system, muscles, and skeleton bones one by one began to take shape. Sixth week, increasing up to 2-4 mm long. The heart begins to beat even though the mother could not hear it. Digestive and respiratory systems begin to appear. Organ hands and feet began to grow like shoots. Seventh week, a 5-13 mm long with a weight of less than 1 gram. Chambers of the heart has formed in the form of right and left ventricle, the airways in the lungs, too, is formed. Shoot organs of the hands and feet continue to grow. Eighth week, the length of approximately 14-20 mm. Indra-like nose, eyelids, ears, and liaison channels between the lungs with throat began to appear. 3 months of pregnancy is a phase that is extraordinary.
Third Month
Ninth week, ear lobe, legs and hands and fingers more and show the form. Fetal movement started but have not felt the mother. His heart rate had been able to be heard using Doppler detector. Long continues to grow around 21-30 mm and the weight can reach 4 grams. Sunday the tenth, the organ in the body begin operational. Brain experiencing rapid growth, about 250 thousand cells are formed every minute requirement. His form as a man more clearly visible with a length between 31-42 mm and weighs about 7 grams. Sunday the eleventh, the length of growing an average of 43-55 mm and weighs about 10 grams. The brain needs to do dinutrisi for maximum growth. Twelfth Sunday, the length ranges from 60 mm with fetal weight can reach 15 grams. That is the first trimester.
