Fetal Development Month by Month

fetal development

So, you're pregnant. Congratulations! The next nine months are going to be long and will require a lot of patience and understanding when it comes to listening to your body and making the necessary choices to keep you and baby healthy. As you begin to plan your pregnancy, take into account what stage your body will be at during each month.


Month 1


During your first month of pregnancy, your baby will accomplish many things - first and foremost, conception, fertilization, and implantation. After a woman ovulates, the egg is normally fertilized within 24-48 hours. The single fertilized cell begins to rapidly divide, and at this point in time is called a zygote.


Many amazing things happen at fertilization. Your baby's entire physical attributes are determined, including gender, hair color, and eye color. Between 7-10 days from fertilization, implantation usually occurs. Implantation should occur within the uterus. If it does not, this is considered an ectopic pregnancy. The amniotic sac, umbilical cord, and yolk sac are already beginning to form. By the end of this month, your baby is approximately 2 milimeters long and beginning the early stages of development.


Month 2


woman in early second month of pregnancy


Your baby is now considered a fetus. Her heart, neural tube, arms, legs, liver, and other major organs are beginning to form. By your 6th week, her heart will be beating and will likely be visible via ultrasound toward the end of the month. The placenta also begins to form, as well as the eyes, ears, mouth, and bones. In this month, your baby's fingers and toes will become present, but they may still be webbed. Her brain and cranial nerves will also begin to form this month. Baby's sex organs will also begin to become visible. Your baby will be approximately 1/2 to 3/4 inch long and will weigh about 1-2 grams by the end of this month.


Month 3


If given an ultrasound now, you would be able to see your baby's arms and legs moving. Baby's heartbeat can be detected by doppler beginning in your third month. Development of the heart and all major organs is complete by the end of the third month. Baby's sex organs continue to develop, but it is still too difficult to differentiate gender. Baby's muscles in trunk, limbs, and head will be developing. Baby's face will be well formed by now, and your baby will look like a baby. By the end of your third month, your baby is 3-4 inches long and weighs about 1 ounce.


Month 4


pregnant woman eating chips


During your fourth month, your baby's hair and teeth begin to form. Your baby will be moving and will be active now, and you may begin to feel baby's movement this month. However, not feeling movements till next month is perfectly normal as well, so not to worry. Your baby's digestive system is forming, and the intestines are now present. Meconium, your baby's first stool, is present in the intestines as well. By the end of this month, it may be possible to determine baby's gender. Your baby will be approximately 5-6 inches long and weigh 5-8 ounces by the end of the month.


Month 5


Your baby is developing a fine hair, called lanugo, which covers the body. Likewise, her eyelashes and eyebrows are developing. Her fingerprints and footprints are now developed. She begins to suck and swallow and may even be found sucking her thumb. Vernix, a white lanolin-like covering, appears on baby to protect her skin. Her ears are developed as well and she may be able to hear you now. Your baby is approximately 7-8 inches long and weighs 3/4-1 pound by the end of this month.


Month 6


Your baby's immune system is developing and she will begin to create her own antibodies. She has developed a hand grip reflex and startle reflex. Her lungs are beginning to develop and alveoli are forming. She is growing and filling out. She looks more and more like the person she will be when she is born. By the end of this month, she will be approximately 9-10 inches long and weigh about 1 1/2-2 1/4 pounds.


Month 7


woman late in pregnancy


Your baby's eyes are open, and she is able to cry. She may be very active now, and others may be able to see her movements. She may have hiccups, which will feel like a jumpy movement. She will continue increasing in body fat, and her bones should be fully developed now. By the end of this month, she is approximately 11 inches long and weighs around 3-3 1/2 pounds.


Month 8


At this point of your pregnancy, there is not a whole lot of new development. However, your baby is growing, maturing, and preparing for life outside the womb. Your baby sleeps most of the time now and has periods of REM sleep. Baby is becoming increasingly cramped for space, but she is still active. Your baby is approximately 13 inches long and weighs around 5-6 pounds at the end of this month.


Month 9


In your last month, which actually extends a little further than nine calendar months, your baby is preparing for birth. She will spend a lot of time resting, but she should still have plenty of active periods. She should be facing head down in preparation for birth. Babies weight and length vary considerably at birth, but a typical range would be between 7-8 pounds and 19-21 inches in length.