Fetal Development - The Amazing Stages Of Embryo Development

From the moment of conception, when sperm meets egg, the resulting embryo constantly undergoes a huge number of changes even when it's still too small to be seen by the naked eye. From here, it grows into a fetus and after nine months emerges into the world as a small baby, whose limbs and organs have (all being well) developed to the point where life outside the uterus is possible. Baby development during pregnancy is an amazing time for parents, and thanks to modern medical technology we now not only know a lot about fetal development, but we're also able to see what unborn babies look like as they grow.

Stages Of Fetal Development

Pregnancy is divided into three trimesters of three months each, during which the fetus experiences different types of changes and growth. Many parents use a pregnancy calendar to track the development of their baby as the nine months go by. Pregnancy calendars can easily be found online, and are often available from healthcare providers.

Fetal Development: First Trimester

Embryonic development doesn't actually begin until around week 5 of the first trimester, after the fertilized embryo implants in the lining of the uterus. Even at this early stage, the baby's vital organs begin to grow (the brain, spinal cord, eyes, ears, and central nervous system). At this stage the baby is probably about 1/16 of inch in length. As the weeks of the first trimester pass, the baby continues to grow until he or she has a small neck, head, genitalia and even ears, eyelids and fingernails. By the end of the first trimester, the baby may have begun moving, but the mother won't feel it yet. By week 12, the fetus is probably about 2 ½ inches in length, so it's likely that the mother's pregnancy still won't be obvious to other people.

Fetal Development: Second Trimester

During this development stage, the baby's sex becomes apparent and can possibly be viewed during ultrasound exams, if the parents choose to do so. The fetus' bones began to grow and fat develops under the skin. The baby begins to hear, swallow, and grow hair, fingerprints and footprints. By the end of the second trimester, the fetus is probably around 9 inches long, and the mother has a visible pregnancy bump.

Fetal Development: Third Trimester

This is the final pregnancy stage and is the time when all the development processes that have already begun are completed. In the last few weeks of the third trimester, the baby gains weight very fast. In the run up to the due date, the baby will open its eyes for the first time, become sensitive to light, and practice breathing. By the end of the last trimester the baby will probably be around 14 inches in length and about 7 ½ pounds in weight - however, the heights and weights of full term babies vary greatly, and many babies that don't fit into this height/weight bracket are born perfectly healthy.

Fetal Development Pictures

Looking at fetal development pictures helps to visualize the growth of the fetus and understand the changes that an unborn child is going through. These pictures can be found on numerous pregnancy sites online or in pregnancy books, and can usually be provided by pregnancy doctors too.

Fetal Movement

Fetal movement can usually be felt from around the halfway mark of the pregnancy (week 20 in the second trimester). When the movement first becomes noticeable, it may feel more like butterflies in the stomach than like a little person moving around, but as the pregnancy develops, the movements become much more definite, and even progresses to kicks (usually not too painful) as the baby moves its limbs.

Twin Fetal Development

Obviously enough, twin fetal development is different to the development of single babies because the growth of two embryos is now taking place in the uterus. A multiple pregnancy is determined at the embryonic stage, either when two separate embryos implant in the uterus, or when one embryo divides and creates multiple fetuses. Women expecting multiples may have a different pregnancy experience because twin pregnancies are a bit riskier.