This week marks the beginning of the fetal period, which lasts until birth. Your baby's body systems, such as circulatory, nervous, reproductive and digestive, are fully formed during this time. His heart is beating approximately 160-170 beats per minute. Your baby is 27 - 35 mm or 1.06 - 1.38 inches with 1/2 the length being attributed to the head. He weighs between 3 - 4 grams (or less then 1/2 ounce), or 4 paper clips.
Also, your baby will become much more active then before, but unfortunately, still too small for you to notice. He will be moving his arms and legs, which can be seen on an ultrasound. Your baby's joints are fully formed, as are his tiny hands, feet, fingers and toes. At this age, he would be able to grab an object if it were placed in his hand, as he grows more and more sensitive to touch. Your baby's eyes are openly most of the time but the eyelids are beginning to fuse – they will stay that way until you reach approximately 25 to 27 weeks. The external genitalia is beginning to be able to show your baby's sex and both the external ears and upper lip are completely formed now. However, your baby's biggest accomplishment this week is the disappearance of the tail!
Also, your baby is breathing. This breathing activity is noticeable as he "breathes" amniotic fluid. Oh, and he is beginning to urinate as well.
There's some good news this week – your morning sickness may begin to ease and give you some relief. You are still tired, moody and nauseated and, much to your unliking, you may start seeing some blotchiness on your face. These can be attributed to the change in hormones.
This is the week where you may begin to show every so slightly. Your abdomen may begin to pooch out, but it will be more from bowel distension than the uterus. Ready or not, your waistline is slowly disappearing. As your blood volume increases by 40-50 percent, you will begin to notice veins on your breasts, legs and tummy more easily. Don't worry. These usually subside shortly after delivery.