Title: Summa Health | First Trimester
Headings: 1st Trimester
1st Trimester
What to expect
Fetal development
Development benchmarks and growth
Changes in the mother's body
The first prenatal visit

Content: The chart provided below provides benchmarks for most normal pregnancies. However, each fetus develops differently. By the end of four weeks
All major systems and organs begin to form
The embryo looks like a tadpole
The neural tube (which becomes the brain and spinal cord), the digestive system, and the heart and circulatory system begin to form
The beginnings of the eyes and ears are developing
Tiny limb buds appear (which will develop into arms and legs)
The heart is beating
By the end of eight weeks
All major body systems continue to develop and function, including the circulatory, nervous, digestive, and urinary systems
The embryo is taking on a human shape, although the head is larger in proportion to the rest of the body
The mouth is developing tooth buds (which will become baby teeth)
The eyes, nose, mouth, and ears are becoming more distinct
The arms and legs are clearly visible
The fingers and toes are still webbed but can be clearly distinguished
The main organs continue to develop and you can hear the baby's heartbeat using an instrument called a Doppler
The bones begin to develop and the nose and jaws are rapidly developing
The embryo is in constant motion but cannot be felt by the mother
From embryo to fetus
After eight weeks, the embryo is now referred to as a fetus (which means offspring). Although the fetus is only 1 to 1 1/2 inches long at this point, all major organs and systems have been formed. During weeks nine-12
The external genital organs are developed
Fingernails and toenails appear
Eyelids are formed
Fetal movement increases
The arms and legs are fully formed
The voice box (larynx) begins to form in the trachea
The fetus is most vulnerable during the first 12 weeks. During this period of time, all of the major organs and body systems are forming and can be damaged if the fetus is exposed to drugs, German measles, radiation, tobacco, and chemical and toxic substances. Even though the organs and body systems are fully formed by the end of 12 weeks, the fetus cannot survive independently. Changes in the mother's body
During pregnancy, many changes are also occurring in the mother-to-be's body. Women experience these changes differently. Some symptoms of pregnancy continue for several weeks or months, while others are only experienced for a short period of time.