Discuss the fetal development through the three trimesters of pregnancy

Question

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Answer 1

Sample response:

First trimester
- Month 1. The embryo resembles a tadpole or tiny shrimp; the buds of arms and legs begin to appear; the heart begins to beat; the embryo is about the size of the eraser on a pencil and weighs less than 1 ounce.
- Month 2. The embryo grows to about 1 inch long; distinct fingers and toes appear; the heart muscle has divided into chambers; facial features are visible; the placenta is functioning, bringing nutrients to the embryo and carrying wastes away; the embryo takes on a more human appearance.
- Month 3. The embryo, now called a fetus, grows to about 3 inches in length; fingers and toes have nails; the fetus begins to move in the uterus, but movements cannot usually be felt by the mother; all vital organs and muscles are formed and functioning by the tenth week. The fetus now weighs about 1.2 ounces (the equivalent of a dozen U.S. pennies).

Second trimester
- Month 4. Fetal movement increases and includes kicking, sucking, and swallowing; about 20 tooth buds develop; fingers and toes are more clearly defined; the sex of the fetus may now be determined by observing the growth of the genitals with ultrasound. The fetus grows to 6 or 7 inches long and now weighs around 6 or 7 ounces.
- Month 5. Fetal activity increases further and may even include rolls, flips, and somersaults; the fetus enters a predictable waking-sleeping cycle; the mother will feel frequent, unmistakable movements of the fetus; fetal eyelashes and eyelids appear; growth accelerates to 8 to 10 inches long and weight increases to nearly a pound by the end of the fifth month.
- Month 6. Fetal skin is red and wrinkled and covered with a protective coating called the vernix; the eyes open and close; the fetus's lungs are "breathing" the amniotic fluid in and out; the fetus is capable of hearing sounds from the outside world; rapid growth continues as the fetus reaches 11 to 14 inches in length and 1.5 to 2 pounds. If born in this month, the baby, though very premature, will have a good chance of survival with specialized intensive care.

Third trimester
- Month 7. The fetus's taste buds have developed, and it may be observed sucking its thumb; muscle tone develops through kicking and stretching; clear responses to external sounds may be observed; layers of fat are forming beneath the skin; internal organs are maturing quickly. If born prematurely at this time, the baby has a high chance of survival and a normal life with proper medical care. The fetus reaches 14 to 16 inches long and about 3 pounds by the end of the seventh month.
- Month 8. The fetus rotates to head-down position; the brain grows quickly; overall growth is now at a rate of a half pound per week; the fetus's kicks and elbow thrusts now become visible from the outside surface of the mother's abdomen; the fetus's internal organs, except for the lungs, are nearly fully developed; the skull bones are flexible and not yet connected to allow them to compress for passage through the birth canal; size is approximately 18 inches long, and weight is 4 to 6 pounds at the end of this month.
- Month 9. The fetal lungs develop fully and are ready to breathe air; the skin typically becomes pink and smooth; the fetus now turns and settles head down, low in the mother's uterus, in preparation for birth; activity decreases, producing fewer noticeable movements; on average, the fetus reaches 18 to 22 inches in length and 6 to 9 pounds as the onset of labor approaches.