So you're period is late and you decide to take a pregnancy test. After a few minutes, the results are POSITIVE!
Congratulations!! You've just found out your pregnant!
Keep reading to learn about the details of a normal pregnancy. Broken down, week by week.
The first trimester of your pregnancy lasts from weeks 1-12, and it begins on the day when you had your last period. You typically find out you are pregnant at 4 weeks.
At week 4 your baby is the size of a poppy seed, measuring about .2 cm. It is referred to as an embryo. The fertilized egg inside of your womb will divide into layers of cells that will become the different parts of a baby’s body. The baby’s nervous system and heart are now developing. The baby already has its own blood vessels and blood that is starting to circulate. A string of blood vessels is what connects you to your baby. This string will become the umbilical cord. The amniotic fluid surrounding the baby will provide a cushion for it throughout the pregnancy.
At week 5 your baby is about 0.9 cm, which compares to a fingernail. The baby’s hands and feet are tiny buds. The bones around the skull will close around their brain. This week the outer layer of the amniotic sac will develop into the placenta. The placenta is what gives the baby the nutrients and oxygen that is needed. This is done through the umbilical cord. The umbilical cord has 3 vessels. The first carrying the oxygenated blood and nutrients to the baby. The other 2 vessels carry blood that has waste products back into your own circulatory system. This will keep bacteria and viruses away from your baby.
At week 6 your baby resembles a tadpole. This is because their back is curved and they have a tail. The baby’s heart will start beating at 24 days. There will be a bulge where the heart is going to develop. It can be hard to see the heartbeat this early, but sometimes a vaginal scan will allow the heartbeat to be seen. There is a bump where the baby’s brain and head will grow. There are tiny dimples on this bump that will turn into ears. There is also a thick area visible which is where the eyes will form. At this point, the baby is covered in a thin layer of translucent skin.
At week 7 your baby is about the size of a grape. The baby’s head is growing faster than the body, making it look almost alien like. This is because the body needs to make room for the brain, which develops rapidly. Cartilage is starting to form in the arm and leg buds. The arms will grow long and flatten out, which will be for the hands to grow. A network of nerves is starting to spread over the baby’s body. This will make little constant motions, as their brain and spinal cord will send signals to the muscles in their body. Soon the baby will be able to feel temperature and have taste sensations.
Your first prenatal appointment should be scheduled between weeks 8 and 10 with your midwife or doctor. By week 8 your baby is starting to look like a little person. It will actually double in size this week. The baby is now referred to as a fetus. The arms are longer than the legs because the head and upper body are growing faster than the rest of the body.
At week 9 the baby is about 2.2 cm long and about the size of a strawberry. Your baby’s genitals are starting to develop. A small bud will grow between the legs, which will either develop into a clitoris or a penis. The color in the baby’s eyes is starting to appear, and the baby has eyelids as well. Taste buds are beginning to form on their tongue. The baby is moving around in the womb, but you won’t be able to feel it at this point.
At week 10 the baby is around 3 cm long. The baby’s face has an upper lip and 2 little nostrils in their nose. Their eyes can react to the light. The jawbone is starting to develop and already has all the milk teeth in it. Your baby is making tiny, jerky movements all the time.
By week 11, your baby is starting to look like a baby. Your baby bump may soon start to show. The baby’s hands now have fingernails. Their fingers and toes will begin to separate. The eye lids have completely closed, and they won’t open again until 26 weeks. The baby’s kidneys are now producing urine and their stomach is producing gastric juice.
Week 12 is the last week of the first trimester. The baby is about the size of a plum. The organs, limbs, bones, muscles and sex organs are now all in place for the baby. The cartilage skeleton will now begin to turn into hard bone. At this point, your baby is starting to swallow.
Week 13 marks the beginning of the second trimester. This is typically where you will start to feel better. The morning sickness and tiredness tends to cease at this point. At this point you might be able to hear the baby’s heartbeat for the first time. The baby weighs around 0.88 ounces. Your baby will only sleep for a few minutes at time at this point.
At week 14 your baby is about the size of a kiwi. They measure about 3.35 inches long. The baby will swallow little sips of amniotic fluid. This goes into their stomach and through their kidneys and will leave their body as urine.
At week 15 your baby is about the size of an apple. Their hearing is developing and they are starting to recognize your voice. They are also able to hear your heartbeat inside your body, which is a comforting sound that your baby will be able to decipher. At this point they can also sense any bright light outside in the world. The baby is covered in fine hair, called lanugo. This will disappear before the birth. It is around this time that babies sometime get the hiccups.
At week 16 your baby is the size of a lemon. It is around this time that you may be able to feel the first signs of life inside your belly. It can feel like a flutter, or a bubbling sensation. It can be hard to tell, so don’t get discouraged. There will be plenty of time to feel that baby inside of you. The muscles in their limbs can now flex. They can make a fist and might even grab at the umbilical cord. They are starting to make facial expressions, such as frowning or squinting, but they actually don’t have control over these muscles yet.
At week 17 your baby is now about 4.72 inches long and weighs about 5.3 ounces. Eyelashes and eyebrows are starting to grow. Their body is starting to fill out and become more proportionate. The baby’s eyes can move, even though their eyelids are still shut. The bone tissue in their feet is beginning to harden. The skeleton is changing from soft cartilage to bone.
At week 18 your baby is measuring 5.5 inches long, about the size of a bell pepper. They can hear all the sounds around them. All of the blood vessels are visible through the skin. The ears are now in their final position. The baby has a protective covering of myelin that will begin to form around their nerves. This is a process that will continue to happen for a year after birth.
At week 19 your baby weighs about 8.5 ounces and measure 6 inches long, about the size of an heirloom tomato. The baby’s brain is devolving in areas such as smell, taste, hearing, vision and touch. Research has shown that the baby can heard your voice, so make sure to talk or read out loud to it. The hair on the baby’s head is beginning to grow. There is a waxy protective coating called the vernix caseosa that will begin to form on the baby’s skin to preserve it in the amniotic fluid.
By week 20 your baby is about 6.5 inches long and weighs about 10.5 ounces, compared to the size of a banana. The baby is starting to swallow more and more, which makes for good practice for the digestive system. The baby is starting to produce meconium, which is a black sticky substance that is from the digestive system. This sustenance will start to accumulate in their bowels and will be passed shortly after birth.
At week 21 the baby now weighs three quarters of a pound and is about 10.5 inches long, similar to the size of a carrot. The baby’s eyebrows and eye lids are now present. The hair on their head and eyebrows is starting to have some color.
At week 22 the baby is about the size of a spaghetti squash. The baby weighs almost 1 pound and is about 11 inches long. The lips, eyelids and eyebrows are becoming more distinct on their face. They eyes have formed, but the iris still lacks any color. The baby’s skin is set with deep wrinkles, which won’t go away until fat will fill them. The baby’s pancreas is steadily developing.
Week 23 the baby is about the size of a large mango. The baby is weighing in at just over a pound and is a little over 11 inches long. The blood vessels in their lungs are developing which will help prepare them for breathing. The baby’s sense of hearing in increasing, making it aware and accustomed to any loud noises they may encounter after birth.
By week 24 the baby is about 1 1/3 pounds and almost 12 inches long, about the length of an ear of corn. The brain is continuing to grow quickly. The taste buds are continuing to develop. The lungs are developing branches of the respiratory tree, along with cells that will produce surfactant. This is a substance that will help their air sacs inflate after they are born.
At week 25 the baby is about the size of a rutabaga. The baby is about 13.5 inches long and weighs 1.5 pounds. The baby is starting to get some baby fat on their body, which helps the wrinkles in the skin start to smooth out.
By week 26 the baby is about 14 inches long and weighs about 1 2/3 pounds, about the size of a scallion. The baby is inhaling and exhaling small amounts of amniotic fluid, which is an important step in the development of their lungs.
Week 27 the baby weighs almost 2 pounds and is about 14.5 inches long, about the size of a head of cauliflower. The baby now sleeps and wakes at regular intervals. The baby can open and close their eyes. Sometimes they might even suck on a finger or two. The brain tissue is continuing to develop, which makes the baby’s brain very active. Baby hiccups are a common movement that you may feel. The baby isn’t bothered by them, and they only last a few moments.
A week 28 the baby is about the size of an eggplant, measuring 14.8 inches long and weighing in at about 2.25 pounds. This is the beginning of the third trimester. The baby is blinking their eyes now, and the eyelids have eyelashes on them. The brain is continuing to develop billions of neurons in it. Now is a great time to be thinking about your birth plan.
By week 29 the baby is about 2.5 pounds and is 15 inches long, compare to a butternut squash. The muscles and lungs are continuing to mature. The head is growing a little bigger to make room for the brain which is continuing to develop. The baby’s bones are soaking up any extra calcium that your body is getting; about 250 milligrams of calcium are deposited into your baby’s hardening skeleton every day.
At week 30 the baby is about 15.7 inches long and weighs almost 3 pounds, about the size of a large head of cabbage. Surrounding the baby is about 1.5 pints of amniotic fluid. As the baby continues to grow, that amount will shrink down. The eyesight is continuing to grow, but even after the baby is born, it will only have 20/400 vision. This means the baby will only be able to see objects that are inches away from their face.
By week 31 your baby is about the size of a coconut. It measures about 16 inches long and weighs about 3.3 pounds. The baby is able to move their head from side to side. The arms, legs and body are beginning to fatten up. The baby is active and moving around a lot, a sign that your baby is active and healthy.
At week 32 your baby is about the size of a large jicama. The baby weighs around 3.75 pounds and is about 16.7 inches long. The baby will gain 1/3 to ½ of their birth weight during the next 7 weeks. The toenails and fingernails are now present. The baby’s skin is becoming soft and smooth in preparation for birth.
By week 33 your baby is about the size of a pineapple. The baby weighs a little over 4 pounds and is about 17 inches long. The baby’s skeleton is hardening. The bones in the baby’s head aren’t fused together, which means they can move and slightly overlap. This makes it easier for the baby to come through the birth canal. These bones don’t actually fuse entirely until early adulthood. This allows the brain to grow and other tissues to expand.
At week 34 the baby is about the size of a cantaloupe. The baby weighs 4.75 pounds and is almost 18 inches long. The central nervous system is maturing, as well as their lungs. The fat layers are continuing to fill up, which will help regulate their body temperature after birth.
By week 35 the baby doesn’t have much room to move around. The baby is about the size of a honeydew melon and weighs about 5.25 pounds and is a little over 18 inches long. The kidneys are now fully developed and their liver is able to process some waste products. Most of the basic physical development is complete. Over the next few weeks the baby will be putting on more weight.
Week 36 the baby is about the size of a head of romaine lettuce, weighing in at about 6 pounds and almost 18.5 inches long. The baby is shedding most of the downy covering of hair that was over their body. They also shed the vernix caseosa, which was the waxy substance that covered and protected their skin during the time in the amniotic fluid. The baby will actually swallow both of these substances, along with any other secretions. The result is meconium, which is a blackish mixture that will be their first bowel movement. The baby is most likely head down and preparing for birth.
By week 37 your due date is rapidly approaching. You're almost there! The baby will still need the next few weeks to allow their brain and lungs to fully mature. The baby now weighs about 6.3 pounds and is about 19 inches long, about the size of swiss chard. At this time, it is not a bad idea to be thinking about birth control options after your baby comes.
By week 38 the baby is really plumping up. The baby weighs about 6.8 pounds and is about 19.5 inches long, about the size of a leek. The baby has a firm grasp, ready to hold onto your finger after birth. The organs are mature and ready for life outside the womb.
At week 39 the baby is considered full term. The baby will continue to build up the fat layers that will help them control their body temperature after birth. The baby is likely about 20 inches and weighs a little over 7 pounds, about the size of a mini watermelon. The outer layers of their skin are falling off as new skin is forming underneath.
Week 40 and you made it! The average newborn weighs about 7.5 pounds and is around 20 inches long, about the size of a small pumpkin. Since their skull bones aren’t fused yet, some baby’s may have a little pointy head after birth. Not to worry, its normal and temporary. This is how they are able to fit through the birth canal during labor.