Learn More About Your Pregnancy

Baby's Growth by Month

First trimester

First month: Congratulations! You’re pregnant! Your baby is already starting to develop. This month the fertilized egg cells have split and are now an embryo and placenta. Your baby’s legs, arms, brain, and spinal cord are starting to form. The baby’s lungs and heart have also started to develop, and your baby’s heart will begin beating around the end of the first month. Your baby is about the size of a poppy seed at the end of the first month. 

Second month: Your baby’s face has started forming but their eyelids stay closed. Your baby’s bones develop and so do the ankles, toes, fingers, and wrists. By the end of this month, your baby is the size of a kidney bean. 

Third month: By the end of the third month, your baby will be about the size of a peach. This month your baby will grow soft nails and muscles, bones, fingers, and toes. At this point, the baby’s hands are bigger than the feet and the baby’s arms are longer than the legs.  

Second trimester

Fourth Month: This month your baby starts growing hair on the head, eyebrows, and body. Baby can move and flex arms and legs and begins to see and hear this month. Your baby’s kidneys are functioning now and at 20 weeks your provider will be able to tell you if you are going to have a boy or girl as your baby’s external sex organs are developing. 

Fifth Month: By the end of the fifth month your baby will be the length of a regular-sized carrot and weigh around 1 pound. Your baby begins sucking and may even start sucking his/her thumb! Your baby will also begin moving around more and you may feel the baby kicking! Your baby is now starting to sleep and wake up at regular times. 

Sixth month: This month your baby’s brain is really developing! Your baby’s eyes are beginning to open, and the lungs are also developedbut not quite working just yet. Your baby weighs almost 2 poundwith wrinkly skin and will keep adding weight these next several weeks. m

Third trimester

Seventh month: Your baby can respond to sound this month so play some music and see what the reaction is! Your baby’s eyes can open and close and can tell if it’s getting darker or lighter outside. Your baby will also spend this month stretching and kicking. By the end of this month, your baby will weigh the same as a large cabbage (3 pounds). 

Eighth month:Pay attention this month to see if you can feel your baby having hiccups. Your baby is now able to taste sweet and sour. Your baby’s brain is still growing, and gaining weight very quickly now, weighing as much as a honeydew melon (over 5 pounds). 

Ninth month: Hang in there! This month is important. Your baby will grow about a pound each week and the lungs are growing so they will be ready to work on their own. Your baby may turn head down during this time to get ready for delivery. Your baby will be the size of a small pumpkin by the time you’re ready to deliver (at 40 weeks).