Information About Fetal Development Month by Month
The growth of your baby is a continuous process that often conveys a sense of awe. The following information is divided into pregnancy’s three trimesters to help you understand your baby’s rapid growth. Milestones in fetal development are also highlighted.
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 days 7-10 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 2mm long and beginning early stages of development.
Your baby is now considered a fetus. Her heart, neural tube, arms and legs, liver and other major organs begin to form. By your 6th week, her heart will be beating and visible via ultrasound. 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, however, they may still be webbed. Her brain and cranial nerves will also begin to form this month. Baby’s sex organs begin to become visible. Your baby is approximately 1/2 inch – 3/4 inch long and weighs about 1-2 grams by the end of this month.
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 are developing. Baby’s face is well formed and your baby looks like a baby. By the end of your third month, your baby is 3-4 inches long and weighs about 1 ounce.
During your fourth month your baby’s hair and teeth begin to form. Your baby will be moving and 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. Your baby’s digestive system is forming and the intestines are 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 is approximately 5-6 inches long and weigh 5-8 ounces by the end of the month.
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.
Your baby’s immune system is developing and she is beginning 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 is approximately 9-10 inches long and weigh in at about 1 1/2-2 1/4 pounds.
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 is increasing in body fat and her bones are fully developed now. By the end of this month, she is approximately 11 inches long and weighs around 3-3 1/2 pounds.
At this point of your pregnancy, there is not a whole lot of new development. However, your baby is growing and 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 very active. Your baby is approximately 13 inches long and weighs around 5-6 pounds at the end of this month.
In your 9th month, which actually extends a little further than 9 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.