switch over of HbF to HbA ??

when does switch over of HbF to HbA occours.....

14 wks
32 wks
34 wks
36 wks


or is it like it starts around 8mth ( ???? wks ???? ) intrauterine life n 90% HbA is seen by 6 mth after being born ???

please refer lipincott 3e page 33.. as this is different from the answers found in different mcq books which say either 14 weeks or 32 weeks .. n when answering please mention in weeks as 8mths can = to 32 /34 weeks


but c lipincott e3 pg 33 it clearly says....HbA synthesis starts around 8mth ( ???? wks ???? ) intrauterine life n 90% HbA is seen by 6 mth after birth !! please quote ur reference dr_atif !!!!!!!


in ak jain HbA production starts around 5th month = 20 weeks ?????

hb f at 4 week of ontrauterine life
20, 40, 60, 80

dr dream the question in DNB was- HbF at 4mnths in a child?
fetal Hb is equal to adult Hb at 2 mnths of age.i.e 50%
complete change over to adult Hb is between 6mnths to 8mnths.

so, at 4 mnths HbF should be around 20-40%.
its confusing!!! answer is 20 or 40.
i hope someone tells us with reference soon!

oh sorry yaar thanks for correction