There are two main periods of development in which children express some sort of separation anxiety.  One in the later part of their first year, 8-10 months, and another during the beginning of toddlerhood, 13-17 months.  The reasons behind the anxiety for each of these two periods are different, for the topic at hand; we are discussing the infant anxiety.  Do not be alarmed, it is quite normal for your child to cry each time you leave the room.  At these times during development children are concerned and need to be assured that you have not disappeared. 

Here is what Dr. Penelope Leach, world-renowned child development expert, has to say in her book Your Baby and Child (1989, p.191-192):

“At six or seven months all the signs of your baby’s devotion are positive ones.  He is nice to everybody but he is nicest of all to you.  His swiftest, widest grins, his longest “conversations,” his earliest laughter and very first “songs” are all saved for you.  But, soon you will see a negative side to all this joy.  If he so much likes to have you with him, it is natural that he should come to dislike having you leave him.  He will probably reach a point, at around eight months, when he tries to keep you in sight every moment of his waking day; when he cannot, he will be uneasy, tearful or even panic-stricken.

Psychologists call this reaction “separation anxiety,” but whether or not you see anything worthy of such a name in your baby depends both on his physical development and on his exact home circumstances.  If he can already crawl when the uneasiness first strikes him, he will keep you in sight simply by crawling after you wherever you go… But if he get anxious about you before he gets mobile, he will be in quite a different situation.  He cannot follow you so he will keep an eagle eye on you instead, starting to whimper whenever you move from his immediate vicinity.”

“To you, it seems totally unnecessary for the baby to cry just because you have gone to the clothes line.  But when the baby loses sight of you, he minds.  You are the center of his world; the mirror in which he sees himself and everything else; his manager, who copes with him and helps him cope with other things.  When you go away from him you know where you are going and how short a time you will be gone, but as far as he is concerned, you might be gone forever.  Out of sight is still out of mind.  He registers your absence but cannot yet hold an image of you in his mind so as to wait calmly, and look forward confidently, to your return.  Over the next few months he will discover “object constancy”: learn that things (and people) do not cease to exist just because they go out of sight and hearing.  And, from continual experience, he will learn that wherever you have gone you will always return.  But right now he only knows that you have vanished and that he feels bereft.”

To help you child through this normal developmental stage, recognize that he is anxious, and needs reassurance.  Try to be courteous to his feelings by keeping him close throughout the day, or by letting him hear you to remind him that you are still nearby. 

One thing that I always did for my own children, and a few of my enrolled children, was to talk to the baby when I moved out of sight.  Continually singing or just telling the child I would be right back became a reminder that I could not be far.  Another thing you can do is play a game (much like peek-a-boo).  While walking out of sight, I would call “Where’s Mommy, Mommy, Here She Comes.” My leaving would always be brief, and when I would return I would smile widely and proclaim “Here She Is!” 

Now do not feel that you need to carry your child everywhere.  You don’t want your child to need to be held constantly, but certainly, if you will be out of sight for more than a few minutes you should bring your child to the room you will be in.  Such as the case with my own children, I have sat my kids in the (empty) baby bathtub while taking a shower, or put the exersaucer in the laundry room while folding clothes.  You can even set up a couple playpens around the house if there is a concern for your child’s safety, so that that way he can be near you wherever you are.

Finally, do not be too terribly concerned about this time period, before you know it he will be quite independent and will struggle when you try to coddle him.  Much like every other stage, before you know it you will miss the days when…