Timeline for Fetal Development

Timeline for Fetal Development
©Little Pampered Babies 2008
Summary:To look at the timeline for fetal development is to look at the miracle of life. Every human being starts life by taking a fantastic journey of growth in those first 9 months spent inside his mother’s womb.
	Let’s follow along with the miracle of prenatal growth. First two weeks of pregnancy: One interesting fact that many people may not know is that pregnancy starts officially about two weeks before conception. This means that it’s starting point is before there’s even a baby. This is because during this time, the uterus grows a layer of tissue rich in blood vessels called the endometrial layer. If conception and implantation does not occur, this layer of tissue is what’s expelled during a woman’s menstrual period.
Conception: This is when a sperm cell from the father fuses with an egg cell or ovum thus resulting in a fertilized egg, also known as a zygote. An egg is expelled into the uterus by a woman’s ovaries during ovulation. This is why ovulation is a woman’s most fertile time. Conception usually occurs two weeks after pregnancy begins.
	Embryonic Development: Once the fertilized egg implants into the wall of the uterus, it immediately begins dividing into embryonic development. This is an extremely critical and fragile time for a developing child because so many important steps are made. First, the single celled human grows into a blastocyst full of embryonic stem cells. The cells divide into those that will be the placenta and those that will make the baby. After only six weeks, the baby’s heartbeat has begun and arms and legs are developing. From the eighth to eleventh weeks, all the major organ systems have begun to form, including the central nervous system. There are also tooth buds, the intestines, joints and the beginnings of the irises.
Fetal Development: At 11 weeks the last phase of growth begins, called fetal development. Organs systems such as the kidneys and liver start functioning. Also, features such as genitals, hair, nails and vocal chords become easily distinguished. From 16 to 20 weeks, the baby has a huge growth spurt. Fat begins to accumulate underneath the thin skin. Meconium, the baby’s waste product, collects in the bowels and is commonly expelled after birth. Sometimes, it is expelled in the womb, and must be suctioned out of the child’s nose and throat at birth. The fetus also spends regular amounts of time awake and asleep at this point. From week 21 to 24, eyebrows and eyelids are completely formed and for boys the testes will descend. From the 25th to 28th week, the most significant development occurs in the lungs as they prepare to breathe air. The child also gains weight everyday to prepare for life outside of the warm, safe womb. At week 28, 90% of all children born will survive, but may have issues with breathing. Brain development also has accelerated growth during this time. Week 29 to 40 are spent finishing lung development and fattening up.

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