The fetal Period
Stage 3 of Human Development
{WEEKS 9 - Birth}
Read:
We have made it to the final stage of prenatal development- the Fetal Period. As you have probably already guessed, after 9 weeks gestation, the developing human is referred to as a fetus. By the beginning of the 9th week the fetus has developed all of the necessary anatomical structures and features that will be present at birth. However, the Fetal Period is by far the longest, stretching roughly 31 weeks or more than 7 months during which time growth continues.
The typical pregnancy lasts 40 weeks, but the fetus is termed full-term once it reaches 36 weeks gestation. It is best if the fetus is carried at least 36 weeks because before that the lungs are not fulled developed and functional.
During the fetal period the developmental processes that took place during the Embryonic Period of prenatal development continue to occur (proliferation, differentiation, ect.) but, it is namely maturation that occurs during this time period. Maturation of the tissues and organs must occur so that at delivery or the time of birth, the fetus will be able to transition to life outside the womb.
The fetus increases in size throughout the Fetal Period. At the beginning of the fetal period , an average fetus is only a few centimeters (about an inch) long and weighs only a fraction of an ounce. However, at the end of pregnancy most babies measure over 50 centimeters (about 20 inches) in length and weigh over 7 pounds.
Look:
Below is a chart showing the relative growth of the fetus over the course of gestation. Note how human the fetus appears by 40 weeks.
{WEEKS 9 - Birth}
Read:
We have made it to the final stage of prenatal development- the Fetal Period. As you have probably already guessed, after 9 weeks gestation, the developing human is referred to as a fetus. By the beginning of the 9th week the fetus has developed all of the necessary anatomical structures and features that will be present at birth. However, the Fetal Period is by far the longest, stretching roughly 31 weeks or more than 7 months during which time growth continues.
The typical pregnancy lasts 40 weeks, but the fetus is termed full-term once it reaches 36 weeks gestation. It is best if the fetus is carried at least 36 weeks because before that the lungs are not fulled developed and functional.
During the fetal period the developmental processes that took place during the Embryonic Period of prenatal development continue to occur (proliferation, differentiation, ect.) but, it is namely maturation that occurs during this time period. Maturation of the tissues and organs must occur so that at delivery or the time of birth, the fetus will be able to transition to life outside the womb.
The fetus increases in size throughout the Fetal Period. At the beginning of the fetal period , an average fetus is only a few centimeters (about an inch) long and weighs only a fraction of an ounce. However, at the end of pregnancy most babies measure over 50 centimeters (about 20 inches) in length and weigh over 7 pounds.
Look:
Below is a chart showing the relative growth of the fetus over the course of gestation. Note how human the fetus appears by 40 weeks.
Image: Yale Medical Group."Fetal Growth from 8 to 40 Weeks." Diagram. Web 27 Sept. 2013. Available from: http://www.yalemedicalgroup.org/stw/Page.asp?PageID=STW023824
Read:
Let's take a look at some of the major events in the Fetal Period by month:
Month 3
The fetus can open and close its fists and mouth. The beginnings of teeth are forming. The baby’s reproductive organs also develop, but gender is difficult to distinguish at this age.
Month 4
The nervous system is starting to function. The reproductive organs and genitalia are now fully developed, and the doctor can see on ultrasound if the fetus is a boy or a girl around 20 weeks gestation.
Month 5
Fetal movements can be felt by the pregnant woman and hair begins to grow on the baby’s head.
Month 6
The fetus can respond to sounds by moving or having an increased pulse.
Month 7
Rapid growth and weight gain commences, and the amniotic fluid begins to diminish.
Month 8
Fetus develops reserves of body fat.
Month 9
The fetus' position changes to prepare for labor and delivery. The baby drops down in the pelvis. Usually, the baby’s head is down toward the birth canal.
Watch:
Please view the following video clip that highlights development in the Fetal Period.
Read:
Let's take a look at some of the major events in the Fetal Period by month:
Month 3
The fetus can open and close its fists and mouth. The beginnings of teeth are forming. The baby’s reproductive organs also develop, but gender is difficult to distinguish at this age.
Month 4
The nervous system is starting to function. The reproductive organs and genitalia are now fully developed, and the doctor can see on ultrasound if the fetus is a boy or a girl around 20 weeks gestation.
Month 5
Fetal movements can be felt by the pregnant woman and hair begins to grow on the baby’s head.
Month 6
The fetus can respond to sounds by moving or having an increased pulse.
Month 7
Rapid growth and weight gain commences, and the amniotic fluid begins to diminish.
Month 8
Fetus develops reserves of body fat.
Month 9
The fetus' position changes to prepare for labor and delivery. The baby drops down in the pelvis. Usually, the baby’s head is down toward the birth canal.
Watch:
Please view the following video clip that highlights development in the Fetal Period.
Video: drmpcfl. "Fetal Growth." Online video clip. YouTube. YouTube, 24 Jan. 2010. Web 27 Sept. 2013.
Read:
Once you have watched the video, you are ready to complete the Fetal Period Activities. Click on the "Next Page" button to continue on to the activities page. To go back to the previous page, click on the "Back" button.
Read:
Once you have watched the video, you are ready to complete the Fetal Period Activities. Click on the "Next Page" button to continue on to the activities page. To go back to the previous page, click on the "Back" button.