The first day of your period marks the start of a new cycle, also known as Cycle Day 1 (CD1).
Your period occurs when the released egg (ovulation) from the previous cycle does not become fertilized, meaning a pregnancy did not occur. Therefore, the lining of the uterus, which is needed to support a pregnancy, is shed, causing bleeding.
Period vs. Withdrawal Bleeding
If you’re using hormonal birth control, the bleeding you may experience is not a period – this bleeding is called withdrawal bleeding. Although this may seem like a period, it’s important to remember that withdrawal bleeding is not the same as a true menstrual bleed.
Hormonal birth control usually stops ovulation, so the bleeding that you get is not triggered by ovulation. You can read more about withdrawal bleeding in this article: Withdrawal bleeding: Overview, causes & symptoms
If you are seeing a Withdrawal bleeding option instead of Period in your app, please refer to the article Why can't I log my period?
How and when to log a period in the Natural Cycles app
You should log your period for each day that you are bleeding, not only to let the algorithm know when your new cycle starts but also to ensure that the algorithm gives you correct period predictions for your coming cycles.
Quick steps to log:
- Open the Natural Cycles app and tap the ‘+’ button to open your Add Data page.
- Select the period flow that you’re experiencing that day (Light, Medium, Heavy).
- Press Save.
If you don’t see the different flow options, you can enable this from the app's top menu > Settings > Trackers > Bleeding flow.
What about light bleeding or spotting?
- Light bleeding at the start or end of your period: Log this as Light Period. Continue logging as a period for every continuous day of bleeding.
- Spotting between periods: If you experience bleeding outside of your period, you can log this as Spotting.
You can read more about this in the article: When to log period vs. spotting
How often does a period occur, and how long does it last?
The length and regularity of your period may vary from cycle to cycle and from person to person—everyone is unique! On average, our Cyclers get their period every 30 days, with bleeding lasting for four days.
To view your personal averages, go to the Today view in your app and tap See Cycle Insights. Here you can see your average cycle length (how often you get your period) and average period length (how long your bleeding usually lasts).