A menstrual period (often just called a period) is when the lining of the uterus sheds and there is a release of blood through the vagina. It's a normal part of puberty. Girls who get their periods can get pregnant if they have sex.

It's important to talk to your child about what to expect so you can give them the information they need and answer any questions.

To help your child get ready for their period: 

• Make sure your child knows what a period is. Be sure they understand that some blood will come out of their vagina, but it's usually only a few tablespoons for the whole period. Explain that some belly cramps or back pain are likely a few days before their period or during their period.
• Talk about period products such as pads, tampons, menstrual cups, and period underwear. When they first get their period, they might feel most comfortable with a pad (rectangles of absorbent material that stick to the inside of their underwear) or period underwear (washable underwear that absorbs blood). If they're interested, you can explain how to use a tampon (small cylinder of soft material inserted into the vagina to absorb the blood) or a menstrual cup (a flexible cup put into the vagina to collect the blood).
• Help your child pack a pad and a change of underwear to carry with them in case they get their period while away from home. 
• Answer your child's questions about periods and how to manage them. Let them know they can always come to you with questions, worries, or concerns.
• When periods first start, they don't usually come every month at first. Reassure your child that this is expected, and that periods get more regular in a year or so.
• Teach your child to track their period after it starts. They can include the day it starts and ends; whether the flow is light, medium, or heavy; and any symptoms they have (such as cramping). While periods might not be regular at first, it can still help them know what to expect.

Your child:

• has breast development or pubic hair before age 7
• has no breast development by age 13
• has had breast development for 4 years without getting a period
• is 16 years old and hasn't gotten a period

How do I know when my child will get their period? There's no way to know for sure when someone will get their period. But signs that it may come soon include:

• breast development that started 1–2 years ago
• hair growing under the arms and in the pubic area
• mucus-like fluid coming from the vagina 
• mood swings from shifting hormones

What causes a period? A period happens when the ovaries release hormones that cause the lining of the uterus to get thicker. This thick lining is ready for a fertilized egg (an egg that has joined with sperm) to attach to it and develop into a baby. If there is no fertilized egg, the body will break down the lining, causing bleeding. This cycle happens about once a month.