The document summarizes fetal development from conception through the first, second, and third trimesters of pregnancy. In the first trimester, the zygote implants and develops into an embryo with a neural tube, notochord, and primitive organs. By 4 weeks, the heart beats and the embryo takes on a cylindrical shape. In the second trimester, organs continue developing and sex can be determined by 14 weeks. Quickening occurs around 18 weeks. In the third trimester, lanugo hair falls out, skin smooths, and babies gain weight and length in preparation for birth.

1. PRESENTED BY
Ms. Flavia Dass
1st year M.Sc. Nursing
KIMS Hubli.

2. First trimester is approximately 13 weeks.
Embryonic period is roughly the period of life from 2nd to 7th
week after fetilization.
 0-2 weeks
 The egg is released from ovary.
 It is fertilized in the fallopian tube by the sperm.
 The fertilized egg called Zygote, differentiates into cluster
of cells called Morula, an later into Blastocyst.
 Blastocyst implants in the endometrium of the uterus.

3.  At 3th weeks
 Neural tube ( rudiments of brain & spinal cord)
 Notochord ( rudiments of vertebrae)
 Coelomic spaces ( rudiments of body cavities)
Are all developed
 Primitive blood cells also develop.
 At 4th week
 Heart starts to beat.
 Longitudinal & transverse folding of the embryonic disk takes
place. ( longitudinal – head fold & tail fold, covert embryo
from straight to curve form, transverse –folding towards the
midline converts the embryo from a flat form to a cylindrical
form.
 By the end of 4th week the embryo has assumed its
salamander look.
 It has rudiments of ears, arms & facial & neck structures.

4. 5th week
 Rapid development of brain results in extensive
growth of head & makes it much larger in relation to
the rest of the body.
 Development take places from cephalic to caudal.
 Eye begin to develop with lens, vesicles, optic cups&
retinal pigment.
6th week
 Nose, mouth & palate begins to take form & the eyelid
become visible.

5. 7th week
 Extensive development of arms & legs occur with clearly
defined fingers & toes.
 Neck region is established.
 Abdomen is less protuberant.
 Urogential development begins.
 By end of 7 weeks it has distinct human characteristics.
By 12th week
 Intestines fully into abdomen.
 External genitalia have male & female characteristics
(not fully formed).
 Can swallow & make respiratory movements, urinates.
 Moves specific parts of limbs & open & shut mouth.

6. Second trimester is about 15 weeks i.e. 13 to 27 weeks.
4th month (14 -17 weeks)
 Head growth slows, while ears move to a higher
elevation on the side of the head & chin becomes
evident.
 Eyes remain closed, body growth accelerates.
 Reflex responses & muscular activity begin.
 Sex is clearly distinguishable by 14th week.
 By 16th week bone development takes place.
 Average crown-rump length 11.5cm & weights between
99 to 113gms .

7.  5th month ( 18 to 20 weeks)
 Rapid body growth continues
 Leg reach their full length & toe nail develop.
 Eyelids remain fused.
 Fetus moves freely.
 Quickening occurs around 18th week.
 The fetal hiccups & mother can feel series of slight rhythmic
jerks.
 By the end of 5th month vernix caseosa covers the entire
body.
(Vernix caseosa –mixture of sebum & epithelial cells, is a thick
cheesy substance that protects the delicate skin of fetus)
 By the end of 5th month average length of fetus is 16.5cms &
weights 341gms.

8. 6th month (23 -27 weeks)
 Hair growth is prominent.
 Fetus is completely covered with lanugo ( fine soft hair).
 Eyebrows,eyelashes & head hair are present.
 The skin is wrinkled, translucent & red, giving an aged
appearance to the fetus.
 Buds for permanent teeth are present.
 Hands make fist.
 Brown fat forms ( scource of energy, heat production &
heat regulation)
 By the end of 6th month average length of fetus is 20cms
& weights 568 gms.

9. Third trimester is approximately 13 weeks ( 28 to 16
weeks).
7th month( 28-31 days)
 The fetus continues to look old & wrinkled though a
little fat storage begins.
 The hair on the baby’s head is longer.
 Suckling reflex is stronger, eyes begin to open & shut.
 Finger nails is present.
 By the end of 7th week average length is 22.5cms &
weights 1023grams.
 Survival may be expected if born.

10. 8th month ( 32- 35 weeks)
 Subcutaneous fat begin to smooth out some of the
wrinkles.
 Body begins to store fat & iron.
 Thick vernix caseosa covers the whole body.
 Hair on head continuous to grow.
 Lanugo is plentiful expect on face.
 Fingernail reaches the ends of fingers.
 Toe nails are present but doesn't reach the end of toes.
 Has control of rhythmic breathing & body temperature.
 The eyes are open.
 At the end of 8th month average length is 27.5cms &
weights 1.7kg.

11. 9th month ( 36-40 weeks)
 Skin is smooth without wrinkles as the subcataneous fat
becomes thicker from additional deposits.
 Baby is rounder, hair is larger , toe nails have reached the
end of toes.
 Plantar creases are visible.
 Prominent chest & protuberant mammary gland in both
sexes.
 Testes are in the scrotum.
 Lanugo has disappeared from most of the body.
 Skull is firm.
 Skin varies in color from white to pink because of
melanin.
 By the term the average length is 31cms & weights 3.2kg.