First step. First tooth. First word. 
These may be some of the milestones you think of with your baby's development. 
But there's also an emotional milestone in your baby's future. It's separation anxiety. And if your baby cries and clings to you when you leave, it's a milestone he or she has already reached. 
This anxious reaction usually peaks between ages 10 months and 18&nbsp;months, according to the <a href="http://www.netreturns.biz/healthinfo/bouncelink.aspx?shortcut=aap" target="_blank">American Academy of Pediatrics</a> (AAP). Most often, it disappears by the time a child turns&nbsp;2. 
It may seem as though your child is moving backward emotionally&mdash;especially if your baby is now fearful around people he or she once liked to be around, such as a relative or babysitter. 
But remember, separation anxiety is normal. It's also a sign that your baby is maturing, the AAP reports. For the first time, your baby knows that he or she is a separate person from you. Your child also understands that there's only one of you&mdash;and you can't be replaced. 
As a result, when you're out of sight, your baby wants you back. However, because babies have little sense of time, your little one doesn't know when&mdash;or even if&mdash;you'll return. It's no wonder, then, that he or she is upset. 
The good news: As your child grows older, he or she will be able to draw on past experiences and realize that you will&mdash;as always&mdash;return. 
In the meantime, these tips from the AAP can help you ease your baby's anxiety when you leave: 
Time your absences. Babies are prone to separation anxiety when they're tired, hungry or sick. So try not to leave your child until after a meal or nap. Also try to stay close by when your baby is ill. 
Distract, then leave. Ask the person you're leaving your baby with to help focus your baby's attention on something entertaining. That might be a reflection in the mirror or a new toy. Then say goodbye. 
Slip away quickly. Once you've left, your baby will soon turn his or her attention to the person who's standing in for you. Typically, a baby's tears stop within minutes of a parent's departure. 
Help your child prepare for your absences. If your baby crawls or toddles off into another room, don't follow right away. Wait a minute or two so that your baby has a taste of independence. Or, when you leave a room your baby is in, say out loud, "I'll be back." If your baby cries while you're out of sight, call out rather than coming right back. 
You're showing your baby&mdash;bit by little bit&mdash;that you can be trusted to always come back when you say you will. 
Reviewed 3/31/2023

Parents: Coping with separation anxiety

Most babies go through a phase in which they don't want mom or dad out of their sight. This is normal, but it's not something you have to give in to. The tips that follow can help you ease your child's anxiety when you have to leave.