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Approximate Timetable of Prenatal Development. Prenatal Development is divided into 3 trimesters. 1 st two months the developing human is called an embryo – from which all body organs develop 2 nd trimester he/she is called a fetus.
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Approximate Timetable of Prenatal Development • Prenatal Development is divided into 3 trimesters. • 1st two months the developing human is called an embryo – from which all body organs develop • 2nd trimester he/she is called a fetus. • The 3rd trimester the baby is growing and could survive with medical care if born prematurely. Ultrasound picture
How Long is Pregnancy? • The “average” pregnancy lasts approximately 40 weeks. That really is more like 9 ½ months than 9 months. • Babies born before 37 weeks are premature and those born after 42 weeks are post mature • It’s better to measure pregnancy in weeks than in months It is divided into Trimesters (3)
Where does life begin? • Scientifically – When the ovum and sperm meet and the ovum (egg) becomes fertilized it is both human – and alive. • So – the answer really is that life begins at conception. • This normally happens in the fallopian tubes. • The fertilized ovum then moves to the uterus where it should implant to continue growing and maturing
From conception to this! What a Miracle!!! So – how does this happen?
First Trimester 1st – 12th week 8 wks • First month – early formation of the layers of cells that become the organs • Amniotic sac forms – (water) • By the end, the embryo is about ¼” • Second month • Grows to about 1 ½”. Bones and muscles round out contours of body, forehead prominent, heart begins beating, limbs elongate, sex organs begin to form
First Trimester 3rd month • Beginning of “fetal” period • Male sexual organs showing more rapidly than female • Tooth buds for all 20 baby teeth • Organs begin functioning • Movement of arms, legs, shoulders, and fingers possible • Mother will not feel the movement yet. 3.5 months
Second Trimester 4th – 6th months (13th week to 26th week) • 4th month • Lower parts of body grow rapidly so that head appears more normal • Back straightens, hands and feet well formed. • More movement – begins to be felt by mother • 5th month • Skin structures attain final form, sweat and sebaceous (oil) glands functioning. • Hair, nails on fingers and toes • Lean and wrinkled • About 1 foot long and weighs about 1 pound ↑ 4 mos ↓ 5mos
2nd trimester6th month • Eyelids which were fused shut, reopen. • Eyes are completely formed • Taste buds on tongue (more than we have!) • Development mostly over – growth to occur now. • Would have chance if born after 24 weeks
Third Trimester27th week to birth • 7th month • Capable of living from this point • Baby can respond to light, music, sound • About 15” long, 3 lbs • 8th and 9th month • Time to “fatten up”! Formation finished. • Lots of movement and activity! • Rapid fetal heart rate