Q. How can I prevent my 9 month old baby girl from being underweight? She really doesn't have a good appetite (even for her formula). Please help!
The short answer is: see your doctor. It is not really a question of under or overweight but more an issue of whether your baby is following her growth curve. A growth curve is the rate at which your child gains weight. So a small baby that is in the fifth percentile of her growth curve will always be considered small but as long as she stays in the ifth percentile over time then she is growing fine (i.e. she was in the fifth percentile for a six month old and is still in the fifth percentile for a 9 month old).
If it is a question of appetite, a lot of times, babies at this age are teething and will sometimes eat less. As long as she's gaining weight she should be fine and her appetite should improve in the next few months. If she isn't gaining weight, then please visit your pediatrician for a check-up.