Everyone's period is slightly different, and odds are, you have a good sense of what's normal for you. But when things start to deviate outside the norm — like a period that starts and stops — it's understandable to have questions. But before you panic-google "my period stopped and then started again two days later," there are a few things you should consider.

For starters, there's a range of normal when it comes to periods, and even something that's kind of jarring, like having your period stopping and starting, can fall into that category. "It's absolutely normal for someone's period to stop and start occasionally," says Meleen Chuang, MD , interim chief of service of ob-gyn at NYU Langone - Hospital Brooklyn. One study found that so-called menstrual irregularities (which include your period starting and stopping) happen in an estimated 14 percent to 25 percent of women of childbearing age.

Normal menstrual cycles last 21 to 35 days, with a period lasting three to seven days, per the Cleveland Clinic . If you find that your periods are regularly outside of those parameters, Dr. Sassin says, it's a good idea to talk to your healthcare provider to try to figure out why this is the case.

Ahead, an ob-gyn break down what causes periods to start and stop and when to see a doctor. Meleen Change , MD, is the chief of service of ob-gyn at NYU Langone-Hospital Brooklyn. Why Does Your Period Start and Stop? If your period starts and stops once and it never happens again, it's pro.