1st Trimester Fetal Development
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1st Trimester Fetal Development
| Tue, 11-28-2006 - 6:47am |
First Month
The blastocyst, as the fertilized egg is called at this stage, completed its journey from your fallopian tube where it was fertilized to your uterus in the first week and has since settled into your nutrient-rich endometrial lining and been dividing and growing feverishly. By the end of this month it has grown to about 1/4 of an inch long, and along with its extended tailbone that makes it look like a tadpole, it already has a head and mouth, eyes (partially covered by eyelid folds), buds that will become arms and legs, the beginning of lungs and a digestive tract, and a heart that will begin to beat at the end of this month. In the meantime, an early version of the placenta, the chorionic villi, and the umbilical cord - which delivers nourishment and oxygen to the baby - are already on the job.
Your little blastocyst is now 10,000 times larger than it was when fertilized!
You have missed your first period and hormones are surging through your body, preparing you for the coming months. You may also notice your breasts are swollen and tender.
Second Month
Your baby is now just under one inch long (measured crown to rump), or about the size of a grape, and is considered an embryo. Its little heart is beating away and he or she is wriggling in your uterus, even though you will not be able to feel the movements for many more weeks. If you are carrying a baby boy, his penis is beginning to appear, although it won't be big enough to see on an ultrasound for another couple months. Its liver is churning out large amounts of red blood cells, and will continue to until the bone marrow forms and takes over this function. Week eight marks the beginning of a very busy developmental stage: its face continues to change as the ears, eyes and the tip of the nose appear; the intestines start to form in the umbilical cord; and your baby's teeth begin to develop under the gums.
You may be experiencing one of the least-favorite symptoms of pregnancy: morning sickness. If so, keep some crackers by your bed and eat a few before getting up in the morning. Keeping a little food in your stomach at all times can help stave off the waves of nausea. Your breasts are probably still sore and your areolas and nipples have darkened, and you may have put on a few pounds (although some women don't and a few even lose a couple pounds during the first trimester due to morning sickness and lack of appetite). You're probably feeling tired and can't wait to climb into bed at the end of the day, and all those hormones raging through your body may have put you on an emotional roller coaster.
Take heart - the nausea, fatigue, and mood swings should all disappear by the end of next month as you near the beginning of your second trimester.
Third Month
Your little fetus is about 2.5 inches long (crown to rump) and weighs nearly an ounce. His or her reflexes are functioning, and the digestive tract is active and secreting bile - all to prepare your baby for life outside of your body. Stem cells, the "mother cells" that will become heart, brain, liver, bone, blood, nerve, and immune cells, continue to differentiate to form your baby's major organs. He or she now looks more like a little person and the head is the biggest part of its body - accounting for nearly 1/2 of its total size. He or she has eyes, a chin, bits of teeth, a nose, and a forehead and the fingers and toes are almost fully formed.
You may begin to regain some of your energy and appetite about now, and although you probably still don't look pregnant, your pants may be getting a little tight. You may also experience indigestion, bloating, and gassiness, thanks to all the progesterone your body is producing. To help relieve some of the discomfort, eat several small meals instead of three bigger ones.
The blastocyst, as the fertilized egg is called at this stage, completed its journey from your fallopian tube where it was fertilized to your uterus in the first week and has since settled into your nutrient-rich endometrial lining and been dividing and growing feverishly. By the end of this month it has grown to about 1/4 of an inch long, and along with its extended tailbone that makes it look like a tadpole, it already has a head and mouth, eyes (partially covered by eyelid folds), buds that will become arms and legs, the beginning of lungs and a digestive tract, and a heart that will begin to beat at the end of this month. In the meantime, an early version of the placenta, the chorionic villi, and the umbilical cord - which delivers nourishment and oxygen to the baby - are already on the job.
Your little blastocyst is now 10,000 times larger than it was when fertilized!
You have missed your first period and hormones are surging through your body, preparing you for the coming months. You may also notice your breasts are swollen and tender.
Second Month
Your baby is now just under one inch long (measured crown to rump), or about the size of a grape, and is considered an embryo. Its little heart is beating away and he or she is wriggling in your uterus, even though you will not be able to feel the movements for many more weeks. If you are carrying a baby boy, his penis is beginning to appear, although it won't be big enough to see on an ultrasound for another couple months. Its liver is churning out large amounts of red blood cells, and will continue to until the bone marrow forms and takes over this function. Week eight marks the beginning of a very busy developmental stage: its face continues to change as the ears, eyes and the tip of the nose appear; the intestines start to form in the umbilical cord; and your baby's teeth begin to develop under the gums.
You may be experiencing one of the least-favorite symptoms of pregnancy: morning sickness. If so, keep some crackers by your bed and eat a few before getting up in the morning. Keeping a little food in your stomach at all times can help stave off the waves of nausea. Your breasts are probably still sore and your areolas and nipples have darkened, and you may have put on a few pounds (although some women don't and a few even lose a couple pounds during the first trimester due to morning sickness and lack of appetite). You're probably feeling tired and can't wait to climb into bed at the end of the day, and all those hormones raging through your body may have put you on an emotional roller coaster.
Take heart - the nausea, fatigue, and mood swings should all disappear by the end of next month as you near the beginning of your second trimester.
Third Month
Your little fetus is about 2.5 inches long (crown to rump) and weighs nearly an ounce. His or her reflexes are functioning, and the digestive tract is active and secreting bile - all to prepare your baby for life outside of your body. Stem cells, the "mother cells" that will become heart, brain, liver, bone, blood, nerve, and immune cells, continue to differentiate to form your baby's major organs. He or she now looks more like a little person and the head is the biggest part of its body - accounting for nearly 1/2 of its total size. He or she has eyes, a chin, bits of teeth, a nose, and a forehead and the fingers and toes are almost fully formed.
You may begin to regain some of your energy and appetite about now, and although you probably still don't look pregnant, your pants may be getting a little tight. You may also experience indigestion, bloating, and gassiness, thanks to all the progesterone your body is producing. To help relieve some of the discomfort, eat several small meals instead of three bigger ones.

