Fetal Development

Pregnancy is the time when your baby depends on you for everything! Not long ago, the first nine months in the womb were a mystery. Recent technology has allowed us to see these unborn miracles grow from conception on. For a beautiful Flash movie of life in the womb, click www.justthefacts.org

Pregnancy is calculated based on 40 weeks, beginning the first day of a pregnant women's last period. By the time a pregnant women realizes she is pregnant, she is already considered four weeks along, even though conception only took place two weeks before.

Day
21

The heart, now in tubular form, begins to beat 21 days after fertilization. The first signs of brain development are evident and the foundation for every organ system is already established and beginning to develop.

Week
6

At just 4 weeks after fertilization the heart is beating about 80 times a minute. The eyes are developing and the arm and leg buds are visible. The structure for the entire central nervous system (brain and spinal cord) has formed.

Week
7

The embryo makes its own blood now. The arm buds begin to resemble tiny paddles and the leg buds look like flippers and the brain begins to control movements of the muscles and organs. The mother has missed her second period and has probably confirmed that she is pregnant.

Week
8

The baby is now about ½ of an inch long from head to bottom. Lungs begin to develop and the kidneys have begun to function. Forty muscle sets begin to operate in conjunction with the nervous system. Some reports show that the embryo’s body responds to touch by reflex.

Week
12

The fetus now sleeps, awakens and exercises its muscles energetically- turning its head, curling its toes, and opening and closing its mouth. It is about 2 inches long and can yawn and suck. The palm, when stroked, will make a tight fist. The fetus breathes amniotic fluid to help develop its respiratory system. The fetus can suck its thumb and the kidneys are able to make urine.

Week
14

By the end of the month, the fetus still weighs less than a half a pound. The mother will probably start to "show". The ears are functioning, and there is evidence that the fetus hears quite a bit: the mother's voice and heartbeat as well as external noises. The umbilical cord transports 300 quarts of fluids per day, completing a round trip every 30 seconds.

Week
24

Survival is now possible outside the uterus. The pregnant woman has been able to feel movement for some time now. The fetus may have head and body hair, and has unique fingerprints. If a sound is especially loud or startling, the fetus may jump in reaction to it.

Week
32

The baby now uses the four senses of vision, hearing, taste and touch. He can recognize his mother's voice. Development is almost complete, and while he waits to be born he will continue to store up fat for insulation and nourishment.

At what Stage

At what stage of fetal development are abortions legal in the United States? Under the Supreme Court's decisions in Roe v. Wade, Doe v. Bolton, and Planned Parenthood v. Casey, abortions may be performed for any reason (socioeconomic, failure of birth control, personal choice) prior to viability (about 24 weeks of pregnancy) and for any reason relating to the mother's physical or psychological health thereafter. In these cases (post-viability abortions), the term "health" has been defined very broadly by the Court to include any matter that might affect a woman's "sense of well-being". In effect, therefore, abortion is legal for any "health" reason throughout pregnancy.

Source: The First Nine Months, (brochure) Focus on the Family, Colorado Springs, CO 1999, 2005, 2008

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