Prior to an Ultrasound visit in your third month, the embryo resembles a tadpole through your first month. Tiny buds develop which will later become arms and legs. The backbone, spinal cord and lungs begin to form; and nerve development begins. The heart also begins to develop and will start beating near the end of this month. The placenta is present but not fully developed. The embryo will be approximately ½ inch long and will weigh a fraction of an ounce at the end of the first month.

During the second month, the embryo goes through rapid development. All major organs and body systems begin to develop, including the brain, lungs, liver and stomach. The heart is functioning. The first bone cells appear. Eyelids form but remain sealed shut. The inner ear begins formation, as do the face and features. Ankles, wrists, fingers, toes and sexual organs are developing. The umbilical cord is present, and the placenta is functioning. The baby looks more like a person than a tadpole and will measure slightly more than an inch and weigh less than 1ounce at the end of this month.

During the third month, Ultrasound welcomes patients to witness the development of their baby. The fingers and toes are more defined and now have soft nails. Earlobes are formed. Buds which will become teeth have formed under the gums. Eyes are almost fully developed but still remain shut. The heart has four chambers and beats at 120 to 160 beats per minute. The heartbeat can be heard for the first time by Doppler at about 10 weeks. Kidneys are developed and begin draining urine to the bladder. Most bones have begun to develop, and the umbilical cord becomes fully formed. By the end of this month, the baby will be about 4 inches long and weigh slightly over an ounce.