You're regularly passing large blood clots
Having the odd blood clot during your period is normal, but if you're consistently having blood clots that are large (anything larger than a golf ball), it could be a sign of uterine fibroids, non-cancerous growths that can develop in your uterus.
You repeatedly soak through a tampon or pad in an hour or less
Bleeding this heavily could be an indication that you have polyps in your uterus or uterine fibroids. If you experience shortness of breath and dizziness with heavy bleeding, you need to see a doctor ASAP. This could be a sign that you’re anemic and may have a hormonal imbalance that needs to be corrected in order to stop or slow the bleeding.
Your period lasts longer than seven days
There can be varying reasons that your period is longer or shorter than expected, like stress. If it's not normal for you, a longer-than-normal period can also be due to polycystic ovary syndrome (PCOS) and uterine polyps.
Your period cycle is less than 20 days
Everyone’s cycle is different but if you’re suddenly having short cycles, it could be a sign of ovulatory dysfunction or a thyroid disorder.
You missed a period
If you’ve been under a lot of stress or are doing a lot of high-intensity exercise, that can cause you to miss a period. But thyroid issues can also make your period stop. If you miss a period and don’t have pain, you’re probably OK to wait it out. But if you keep missing periods, you should consult your local GP. It could be a sign of a hormonal imbalance that needs to be fixed.