A. If your baby otherwise seems to be growing and developing normally, then that is probably not a sign of autism. Among other normal developmental milestones that you would expect at this age include that your baby smiles, is usually comforted or soothed when she is picked up, follows objects past the midline of her face, make 'ooo' and 'aah' type cooing noises, and maybe has begun laughing. You should definitely discuss it with your Pediatrician if you don't think your baby's behavior is normal though.
The symptoms you describe could also be seen in infants with high muscle tone, especially if her muscles usually seem extra stiff. This is something that you should also discuss with your Pediatrician, but it isn't really related to autism at all.
Among the early signs and symptoms that parents and Pediatricians look for to alert them that a child needs further evaluation for autism include:
- not smiling by six months of age
- not babbling, pointing or using other gestures by 12 months
- not using single words by age 16 months
- not using two word phrases by 24 months
- having a regression in development, with any loss of language or social skills
Keep in mind that autism usually isn't diagnosed until about age 3, although some experts believe that some children begin to show subtle signs as early as six months of age.
There is also an autism study that showed that some children with autism had abnormal brain growth. Specifically, they had a smaller than average head size at birth (at the 25th percentile), but then had a period of rapid head growth during which their head size moved up to the 84th percentile by age 6-14 months. But rapid head growth is not a sign in all kids with autism.
In general, if you are concerned about your child's development, especially if you think that they might have autism, you should talk to your Pediatrician and consider a more formal developmental evaluation.
And keep in mind that when a child arches her back a lot, it can be a sign of gastroesophageal reflux (Sandifer Syndrome), although you would usually expect other symptoms, like spitting up and being fussy.
Getting An EvaluationOne of the frustrating things that occurs when parents think something is wrong with their child's development is that they may be told 'not to worry' or that they 'should just wait.' Experts think that it is better for parents to trust their instincts and get their child evaluated if they think that they aren't developing normally. This guide from First Signs is a good resource for parents trying to share their concerns with their Pediatrician.
Your local early childhood development program may also be able to do an evaluation if you are concerned about your child's development.