Thanks for writing to health care magic.
There are several causes for a low birth weight
First we should know if the baby is born term or preterm. (What I mean to say is after completion of 37 weeks of gestational age
or before that)
A preterm born before completion of 37 weeks of gestational age is normally low birth weight.
A term baby can also be low birth weight because of several reasons.
These include nutritional status of the mother, other problems with the mother like anemia
, etc etc.
The injections and PCOD
may not be responsible for low birth weight
Hope this helps.