Monday, 5 September 2011

Fetal Stage “ Fetal Growth and Development”


Entire pregnancy days – 266 – 280 days    37 – 42 weeks

Differentiation of Primary Germ layers
* Endoderm
        1st week endoderm – primary germ layer
Thyroid – for basal metabolism
Parathyroid - for calcium
Thymus – development of immunity
Liver – lining of upper RT & GIT

* Mesoderm – development of heart, musculoskeletal system, kidneys and repro organ

* Ectoderm – development of brain, skin and senses, hair, nails, mucus membrane or anus & mouth
First trimester:
1st month -     Brain & heart development
GIT& resp Tract – remains as single tube      
1. Fetal heart tone begins – heart is the oldest part of the body
2. CNS develops – dizziness of mom due to hypoglycemic effect
                                                        Food of brain – glucose      complex CHO – pregnant womans food (potato)

Second Month
1.       All vital organs formed, placenta developed
2.       Corpus luteum – source of estrogen & progesterone of infant – life span – end of 2nd month
3.       Sex organ formed
4.       Meconium is formed

Third Month
1.       Kidneys functional
2.       Buds of milk teeth appear
3.       Fetal heart tone heard – Doppler – 10 – 12 weeks
4.       Sex is distinguishable

Second Trimester: FOCUS – length of fetus

Fourth Month
    1. lanugo begins to appear
    2. fetal heart tone heard fetoscope, 18 – 20 weeks
    3. buds of permanent teeth appear

Fifth Month 
1.       lanugo covers body
2.       actively swallows amniotic  fluid
3.       19 – 25 cm fetus,
4.       Quickening- 1st fetal movement. 18- 20 weeks primi, 16- 18 wks – multi 
5.       fetal heart tone heard  with or without instrument

Sixth Month
1.       eyelids open
2.       wrinkled skin
3.       vernix caseosa present

Third trimester: Period of most rapid growth. FOCUS: weight of fetus
Seventh Month – development of surfactant – lecithin

Eighth Month
1.       lanugo begin to disappear
2.       sub Q fats deposit
3.       Nails extend to fingers


Ninth Month 
1.       lanugo & vernix caseosa completely disappear
2.       Amniotic fluid decreases

Tenth Month – bone ossification of fetal skull

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