The embryo is in three layers at this point. Your doctor may even be able to detect it on an ultrasound. Those buds of arms and legs have turned into paddles. Your baby is still as tiny as a pencil eraser, but they already have little nostrils. The lenses of their eyes are beginning to form. Their upper lip and nose are also starting to take shape.
Their toes are forming, too. Their eyelids and ears are getting more refined. Your baby started as a tiny speck and is still less than 2 inches long from crown to rump. Still, your little one is starting to look like a tiny newborn.
From week 11 onward, your baby will continue to develop and grow until the end of your pregnancy. Their face has taken on more human characteristics. Week 13 marks the start of the second trimester. During this stage, your fetus is looking and operating more like a real baby. Early on, their sex organs are developing, their bones are getting stronger, and fat is starting to accumulate on their body.
Midway through, their hair becomes visible, and they can suck and swallow. They can start to hear your voice, too. In the first half of this stage, your fetus starts to open their eyes, practices breathing in amniotic fluid, and becomes covered in vernix caseosa. Toward the end, they are gaining weight more quickly, making lots of big movements, and starting to crowd themself in the amniotic sac.
Your fetus starts the third trimester at 10 inches from crown to rump, and grows to 18 to 20 inches. The length and weight of babies at delivery varies greatly. Electrical activity begins in the developing brain and nervous system. The brain continues to form. The lungs begin to form. Fingers and toes begin to form, and arms and legs have grown longer.
Feet and hands can be distinguished and now have fingers and toes digits , which may still be webbed. The shell-shaped parts of the baby's ears are forming, and the baby's eyes are visible. The upper lip and nose have formed. The trunk of the baby's body is beginning to straighten. The beginnings of all key body parts are present, although they are not completely positioned in their final locations.
Eyes, ears, arms and legs are identifiable. These are done to find inherited diseases, like sickle-cell anemia, Tay-Sachs disease. Screening tests. These are done to find infectious diseases, like sexually transmitted diseases. The first prenatal visit is also an opportunity to ask any questions or discuss any concerns that you may have about your pregnancy. A healthy first trimester is crucial to the normal development of the fetus. The mother-to-be may not be showing much on the outside, but inside her body all the major body organs and systems of the fetus are forming.
Amniotic sac. A sac filled with amniotic fluid, called the amniotic sac, surrounds the fetus throughout the pregnancy. The amniotic fluid is liquid made by the fetus and the amnion the membrane that covers the fetal side of the placenta that protects the fetus from injury.
It also helps to regulate the temperature of the fetus. The placenta is an organ shaped like a flat cake that only grows during pregnancy. It attaches to the uterine wall with tiny projections called villi. Fetal blood vessels grow from the umbilical cord into these villi, exchanging nourishment and waste products with the mother's blood. The fetal blood vessels are separated from the mother's blood supply by a thin membrane. Umbilical cord.
The umbilical cord is a rope-like cord connecting the fetus to the placenta. The umbilical cord contains two arteries and a vein, which carry oxygen and nutrients to the fetus and waste products away from the fetus. It is during this first trimester that the fetus is most susceptible to damage from substances, like alcohol, drugs, certain medicines, and illnesses, like rubella German measles.
Click to Enlarge. The most dramatic changes and development happen during the first trimester. During the first 8 weeks, a fetus is called an embryo.
Just as each child grows and matures at different rates and at different times, so does that same child as it begins its life in the womb.
The chart below provides benchmarks for most normal pregnancies. However, each fetus develops differently. The neural tube which becomes the brain and spinal cord , the digestive system, and the heart and circulatory system begin to form.
0コメント