Your Pregnancy Week by Week
First Trimester: Weeks 1 to 14
The first 14 weeks of pregnancy are referred to as the first trimester. All of your baby's organs are forming during this part of the pregnancy. Therefore, it is particularly important for you to take care of yourself and your baby during this time. Avoiding unhealthy habits, such as smoking and alcohol, are obviously important.
Week 1: The egg is fertilized and attaches to the wall of the uterus
Week 2: The egg cell divides over and over into new cells. The embryo and placenta start to form. This is the time when you typically miss your period
Week 3: The baby's body begins to take shape and the placenta is now fully formed
Week 4: Your baby is about as big as a doodle bug, but the heart, digestive system, and baby's blood are forming
Week 5: Your baby's heart starts to beat
Week 6: The eyes and ears are forming
Week 7: Your baby now has eyes, a nose, a mouth and lips. Now the bones and teeth are starting to form
Week 8: About 1 inch long and growing fast
Week 9: Now it is called a "Fetus." It is starting to form its boy and girl parts
Week 10: The lower part of the body and legs are growing fast
Week 11: All of your baby's organs start to work and it starts to urinate
Week 12: Your baby can now swallow and sucks its thumb. The lungs are forming and breathing movements begin. However, the baby is getting all of its oxygen through the placenta. The placenta and umbilical cord will act as the babies lungs, liver, kidneys, and digestive system until birth. Your baby is protected from many illnesses because your immunity will pass through the placenta.
Second Trimester: Weeks 15 to 26
The second trimester is a time of many changes for you and your baby. This is the time when your body will go through significant changes. Your baby's body is also changing in dramatic ways.
Week 13: The placenta is now fully functional. Your baby is still called a "Fetus," but is starting to look like a little person with a very big head
Week 14: The nervous system is up and running. The muscles and bones are ready for action.
Week 15: Your baby weighs about as much as a large orange. On ultrasound you will see obvious and frequent movements. You may even start to feel flutters in your belly (called "quickening"). Most women will not feel this until around 20 weeks.
Week 16: Your baby is now a complete person. All of the major organs - heart, liver, lung, brain - are formed. In the next few weeks, things slow down as your baby just focuses on getting bigger.
Week 18: Have you ever been in the water too long? Your skin gets shriveled and wrinkly. To prevent that from happening to your baby, a fine coating of oil forms on your baby called "vernix." The baby's fine hair (called "Lanugo") keeps the vernix from washing off in your amniotic fluid.
Week 19: The eyebrows and eyelashes begin to grow. You may notice your breasts are starting to get bigger, and you may even notice some leaking. This first milk is called colostrum. By the time you deliver, you will have plenty of thick syrupy colostrum to feed your baby
Week 20: You will start to notice movement. You will also notice your baby has favorite times to move around, and quiet times for sleeping. Your baby is already setting a schedule for itself. This may let you know what to expect after delivery.
Week 22: Your baby is getting heavier! Its bones are getting thicker as its skeleton grows. You will notice about a 3-4 pound weight gain at this point. Much of this is calcium from your baby's bones.
Week 24: The baby weighs about 28 ounces (about 2 pounds); as much as a bag of sugar. Its eyelids have formed and we occasionally see blinking on ultrasound.
Week 26: All of your baby's organs are functioning fully and just need time to grow.
Third Trimester: Weeks 27 to Delivery
Congratulations! You are now in the home stretch of pregnancy. Your baby is really starting to make its presence felt now. In these last months of your pregnancy, your baby will be focused primarily on growth. Here's what will be happening with your baby's development in the next few weeks.
Week 27: This week your baby's lungs start gearing up to work after the baby is born. Your baby will start to "practice" breathing. On the ultrasound, you might even be able to see the baby's chest rise and fall. The baby is not breathing air yet; he is still surrounded by fluid. The amniotic fluid goes in and out of the baby's lungs. A substance called surfactant is in the fluid. Surfactant coats the little sacs inside the lungs so they will work better after the baby is born.
Week 28: Your baby has achieved about 2/3 of its growth. You will notice your baby's movements becoming more predictable. At this time in your pregnancy we start to recommend kick counts when you notice your baby's movements slowing. While resting, you should count kicks at least 10 times in every 2 hour period.
Week 29: Your baby is fattening up. Extra fat stores are forming to give your baby that "plump" look. Fat works to insulate your infant so it will not get cold as quickly.
Week 30: Your baby's movements will become stronger around this time. These movements may keep you up at night and may cause occasional abdominal discomfort.
Week 32: This week your baby's is looking less wrinkled as its skin fills out. It has grown to to be a little more than 1 foot in length.
Week 34: Your baby is weighing about 5 pounds. The smaller more rapid kicks are now being replaced by less frequent but stronger kicks. Your baby's body can almost function on its own. Most baby's born at this time can breathe room air and drink breastmilk.
Week 36: At this time your baby is growing about a pound per week. You baby is continuously getting antibodies from you through the placenta that help your baby fight off infections. So if there are diseases your are immune to (like mumps or measles), your baby will be immune to them for about 3-4 months; longer if you breastfeed.
Week 37 to Birth: Did you know that only about 1/20 women will deliver their baby on their due date. Over half of women will give birth within 10 days of their due date. During these last few weeks your baby will settle into the birth canal and prepare itself for delivery. Although we consider a baby to be "term" at 37 weeks, the onset of natural labor is your body's way of signaling that your baby is completely ready to be born.
First Trimester: Weeks 1 to 14
The first 14 weeks of pregnancy are referred to as the first trimester. All of your baby's organs are forming during this part of the pregnancy. Therefore, it is particularly important for you to take care of yourself and your baby during this time. Avoiding unhealthy habits, such as smoking and alcohol, are obviously important.
Week 1: The egg is fertilized and attaches to the wall of the uterus
Week 2: The egg cell divides over and over into new cells. The embryo and placenta start to form. This is the time when you typically miss your period
Week 3: The baby's body begins to take shape and the placenta is now fully formed
Week 4: Your baby is about as big as a doodle bug, but the heart, digestive system, and baby's blood are forming
Week 5: Your baby's heart starts to beat
Week 6: The eyes and ears are forming
Week 7: Your baby now has eyes, a nose, a mouth and lips. Now the bones and teeth are starting to form
Week 8: About 1 inch long and growing fast
Week 9: Now it is called a "Fetus." It is starting to form its boy and girl parts
Week 10: The lower part of the body and legs are growing fast
Week 11: All of your baby's organs start to work and it starts to urinate
Week 12: Your baby can now swallow and sucks its thumb. The lungs are forming and breathing movements begin. However, the baby is getting all of its oxygen through the placenta. The placenta and umbilical cord will act as the babies lungs, liver, kidneys, and digestive system until birth. Your baby is protected from many illnesses because your immunity will pass through the placenta.
Second Trimester: Weeks 15 to 26
The second trimester is a time of many changes for you and your baby. This is the time when your body will go through significant changes. Your baby's body is also changing in dramatic ways.
Week 13: The placenta is now fully functional. Your baby is still called a "Fetus," but is starting to look like a little person with a very big head
Week 14: The nervous system is up and running. The muscles and bones are ready for action.
Week 15: Your baby weighs about as much as a large orange. On ultrasound you will see obvious and frequent movements. You may even start to feel flutters in your belly (called "quickening"). Most women will not feel this until around 20 weeks.
Week 16: Your baby is now a complete person. All of the major organs - heart, liver, lung, brain - are formed. In the next few weeks, things slow down as your baby just focuses on getting bigger.
Week 18: Have you ever been in the water too long? Your skin gets shriveled and wrinkly. To prevent that from happening to your baby, a fine coating of oil forms on your baby called "vernix." The baby's fine hair (called "Lanugo") keeps the vernix from washing off in your amniotic fluid.
Week 19: The eyebrows and eyelashes begin to grow. You may notice your breasts are starting to get bigger, and you may even notice some leaking. This first milk is called colostrum. By the time you deliver, you will have plenty of thick syrupy colostrum to feed your baby
Week 20: You will start to notice movement. You will also notice your baby has favorite times to move around, and quiet times for sleeping. Your baby is already setting a schedule for itself. This may let you know what to expect after delivery.
Week 22: Your baby is getting heavier! Its bones are getting thicker as its skeleton grows. You will notice about a 3-4 pound weight gain at this point. Much of this is calcium from your baby's bones.
Week 24: The baby weighs about 28 ounces (about 2 pounds); as much as a bag of sugar. Its eyelids have formed and we occasionally see blinking on ultrasound.
Week 26: All of your baby's organs are functioning fully and just need time to grow.
Third Trimester: Weeks 27 to Delivery
Congratulations! You are now in the home stretch of pregnancy. Your baby is really starting to make its presence felt now. In these last months of your pregnancy, your baby will be focused primarily on growth. Here's what will be happening with your baby's development in the next few weeks.
Week 27: This week your baby's lungs start gearing up to work after the baby is born. Your baby will start to "practice" breathing. On the ultrasound, you might even be able to see the baby's chest rise and fall. The baby is not breathing air yet; he is still surrounded by fluid. The amniotic fluid goes in and out of the baby's lungs. A substance called surfactant is in the fluid. Surfactant coats the little sacs inside the lungs so they will work better after the baby is born.
Week 28: Your baby has achieved about 2/3 of its growth. You will notice your baby's movements becoming more predictable. At this time in your pregnancy we start to recommend kick counts when you notice your baby's movements slowing. While resting, you should count kicks at least 10 times in every 2 hour period.
Week 29: Your baby is fattening up. Extra fat stores are forming to give your baby that "plump" look. Fat works to insulate your infant so it will not get cold as quickly.
Week 30: Your baby's movements will become stronger around this time. These movements may keep you up at night and may cause occasional abdominal discomfort.
Week 32: This week your baby's is looking less wrinkled as its skin fills out. It has grown to to be a little more than 1 foot in length.
Week 34: Your baby is weighing about 5 pounds. The smaller more rapid kicks are now being replaced by less frequent but stronger kicks. Your baby's body can almost function on its own. Most baby's born at this time can breathe room air and drink breastmilk.
Week 36: At this time your baby is growing about a pound per week. You baby is continuously getting antibodies from you through the placenta that help your baby fight off infections. So if there are diseases your are immune to (like mumps or measles), your baby will be immune to them for about 3-4 months; longer if you breastfeed.
Week 37 to Birth: Did you know that only about 1/20 women will deliver their baby on their due date. Over half of women will give birth within 10 days of their due date. During these last few weeks your baby will settle into the birth canal and prepare itself for delivery. Although we consider a baby to be "term" at 37 weeks, the onset of natural labor is your body's way of signaling that your baby is completely ready to be born.