How Your Baby Grows During the Fifteenth Week
Your baby's crown-to-rump length is 4-5 inches long now and he weighs around 50 grams (1.75 ounces). A fine hair, called lanugo covers his body in a protective fashion.
The baby's skin is very thin and the growing web of blood vessels would be clearly seen if you were able to see him. If viewed by ultrasound, you might see him sucking his thumb or fist.
The ossification, or hardening of the baby's bones has continued at such a pace, that if you were to take an X-Ray now, his skeleton would be visible. X-Ray radiation is unsafe for your developing fetus, however, so doctors will never do them on a pregnant woman. His soft bones will continue to add calcium and harden over the next months so a pregnant mother must make sure she is eating a calcium rich diet.
Your baby's hair follicles may now begin producing pigment so if your son has the genes for black, brown or red hair, these colors will begin to show.
What the Mother Feels During the Fifteenth Week
By this point in her pregnancy, an expectant mother's blood circulation has increased by 20%. Her heart is working harder than ever to move a growing volume of blood, and provide enough oxygen to her growing fetus. An iron rich diet is important to make sure the level of red blood cells stays high enough, as the blood volume continues to rise in the coming weeks.
The uterus has grown much larger and is now just a few inches below the belly button. It will be obvious to you, the changes in your body, when you place your hands on your stomach. Tighter clothing that used to be just form-fitting, might not fit at all anymore, or may look wrong if you squeeze into them.
Resources:
The Pregnancy Book: Month-by-Month by Dr. Sears
Your Pregnancy Week by Week by Lesley Regan
The Complete Book of Pregnancy and Childbirth by Sheila Kitzinger
