Stages of Prenatal Development

Stage 1: Germinal Stage

¡     Conception to 2 weeks

¡     Cell divisions

¡     Blastocyst embedding on the wall of uterus

¡     Amnion, placenta and umbilical cord beginning to form

¡     The placenta will begin to nourish the baby, remove the baby’s waste, exchange gases between mother and baby and provide the baby with needed hormones.

Stage 2: Embryonic Stage

¡     2 weeks through 8 weeks

¡     Internal organs (heart, liver, digestive system, brain and lungs) developing

¡     Tissue segments (future vertebrae) in the spinal column forming

¡     Limb buds appearing

¡     Ears and eyes beginning to form

¡     The baby does not yet have solid bones but is supported by cartilage.

¡     The baby now receives good and harmful substances from the mother’s placenta through the umbilical cord.  That why the mother’s health habits become very important during this stage.

Stage 3: The Fetal Stage

n      The Fetal Stage lasts from the 9^th to the 36^th week

¡     9 weeks

n      Facial features are forming

n      Limbs and hands, feet, fingers and toes are developing

¡     12 weeks (3 months)

n      3” long; weight 1 ounce

n      Muscles are forming

n      Teeth and vocal cords are developing

n      Eyelids and nails are appearing

¡     16 weeks (4 months)

n      6-8 inches long; weight 5-6 ounces

n      Lanugo (cottony growth) appearing

n      Heartbeat is audible with a stethoscope

n      Eyebrows and eyelashes are growing

¡     20 weeks (5 months)

n      10 – 12 inches long; weight 1 pound

n      Sweat glands forming

n      Head hair appearing

n      Vernix caseosa (cheesy material) covering the body

n      Skin developing

¡     24 weeks (6 months)

n      14 inches long; weight 2 pounds

n      Eyes maturing

n      Taste buds developing

¡     28-36 weeks (7 months – birth)

n      Growing rapidly

n      Lanugo disappearing

n      Fatty tissue developing under the skin

n      Body organs maturing

n      By the fourth month the baby has grown enough to give the mother’s abdomen a pregnant look

n      Two milestones occur in this stage

¡     In the third month the parents-to-be may be able to heart the baby’s heartbeat for the first time.   Between the fourth and fifth month she will feel the baby move.  These movements are called quickening.

¡     The second milestone is reached when the baby reaches about 26 weeks of age.  This is called the age of viability.  By this time the baby’s brain has more control over body systems

¡     In the ninth month the fetus receives immunities from the mother