I apologize ... I also should have asked how long was the child in a placement?
Has the child been evaluated by a pediatric neurologist? Or person who specializes in development? Without being able to view the child and/or examine her myself ... there are a number of factors that could have contributed to a developmental delay ...
But first and foremost would be to enroll the child in an "early intervention program" NOW ... these programs are wonderful!! and can do some amazing things with helping a child to catch up. My son was in a program called "Stride" when we lived in Wyoming. When he started the program he was 2 1/2 years old, but delayed to about 18 months. By the time, he was 4 years old, he was caught up and basically on track. (He was a traumatic, c-section birth to a teenage mother.)
Okay ... a little background -- when a child is in foster care, the foster parent is required to take that child to the pediatrician at regular intervals, have the child immunized, and follow all treatment guidelines etc. We (Ca.) have a team of PHN's (public health nurses) who also monitor the children ... and the social worker can at any time request the PHN evaluate a child. We (the S.W.) are also trained to be observant for physical, emotional, developmental delays, problems etc. Although, sometimes things aren't evident until the child is older ...
I don't know what may have happened with your child ... but I would not delay in doing the following (if you haven't yet done so) ... Pediatrican evaluation, followed by possible evals by physical therapist, and/or occupational therapist.
Things to be concerned about would be: Cerebral Palsy, Autism, Muscular Dystrophy, Cystic Fibrosis to name a few ... but please don't obsess about them... you need for the child to have a complete evaluation first, and then go from there ...
Another point would be ... IF there was a connection with developmental delays and removing a newborn from the birth parent and placing in foster care ... the rates would be through the sky ... and that just isn't the case ...
(At least not here in the States. I could tell you lots for other countries though).
I hope this helps you a bit ...
~Marilee