Fingernails and toenails form, and the baby's sex is now identifiable. The baby breathes amniotic fluid to help develop and strengthen the respiratory system. Vocal cords are complete, and at times it appears as if this little baby is crying. Bone marrow is forming, and the heart can be plainly heard as it pumps up to 25 quarts of blood each day. Facial expressions similar to the baby's parents can be identified at this time.
Fine hair begins growing on the head, eyebrows and eyelashes.
The baby learns to grip and suck his or her thumb. Sleeping habits develop and the mother often feels her baby move and stretch, particularly when she is resting. Interestingly, babies at this stage have responded to sounds in frequencies too high and low for adults to hear. By the end of this month the baby is about 12 inches long and weighs about one pound. Babies born at this stage of development have survived.